U.S. patent application number 11/102298 was filed with the patent office on 2005-08-18 for roadway-powered electric vehicle system having automatic guidance and demand-based dispatch features.
Invention is credited to Ross, Howard R..
Application Number | 20050178632 11/102298 |
Document ID | / |
Family ID | 27537771 |
Filed Date | 2005-08-18 |
United States Patent
Application |
20050178632 |
Kind Code |
A1 |
Ross, Howard R. |
August 18, 2005 |
Roadway-powered electric vehicle system having automatic guidance
and demand-based dispatch features
Abstract
A roadway-powered electric vehicle (RPEV) system includes: (1)
an all-electric vehicle; and (2) a roadway network over which the
vehicle travels. The all-electric vehicle has one or more onboard
energy storage elements or devices that can be rapidly charged or
energized with energy obtained from an electrical current, such as
a network of electromechanical batteries. The electric vehicle
further includes an on-board controller that extracts energy from
the energy storage elements, as needed, and converts such extracted
energy to electrical power used to propel the electric vehicle. The
energy storage elements may be charged while the vehicle is in
operation. The charging occurs through a network of power coupling
elements, e.g., coils, embedded in the roadway. The RPEV system
also includes: (1) an onboard power meter; (2) a wide bandwidth
communications channel to allow information signals to be sent to,
and received from, the RPEV while it is in use; (3) automated
garaging that couples power to the RPEV for both replenishing the
onboard energy source and to bring the interior climate of the
vehicle to a comfortable level before the driver and/or passengers
get in; (4) electronic coupling between "master" and "salve" RPEV's
in order to increase passenger capacity and electronic actuators
for quick-response control of the "slave" RPEV; (5) inductive
heating coils at passenger loading/unloading zones in order to
increase passenger safety; (6) an ergonomically designed passenger
compartment; (7) a locating system for determining the precise
location of the RPEV; and (8) a scheduling and dispatch computer
for controlling the scheduling of RPEV's around a route and
dispatch of RPEV's based on demand.
Inventors: |
Ross, Howard R.; (Richmond,
CA) |
Correspondence
Address: |
PETER K HAHN
LUCE, FORWARD, HAMILTON, SCRIPPS, LLP.
600 WEST BROADWAY
SUITE 2600
SAN DIEGO
CA
92101
US
|
Family ID: |
27537771 |
Appl. No.: |
11/102298 |
Filed: |
April 8, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11102298 |
Apr 8, 2005 |
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10279775 |
Oct 23, 2002 |
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6879889 |
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11102298 |
Apr 8, 2005 |
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10097531 |
Mar 12, 2002 |
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10097531 |
Mar 12, 2002 |
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09583455 |
May 30, 2000 |
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6421600 |
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09583455 |
May 30, 2000 |
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09429835 |
Oct 29, 1999 |
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09429835 |
Oct 29, 1999 |
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09290033 |
Apr 8, 1999 |
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09290033 |
Apr 8, 1999 |
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09126913 |
Jul 30, 1998 |
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09126913 |
Jul 30, 1998 |
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08934477 |
Sep 19, 1997 |
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08934477 |
Sep 19, 1997 |
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08238990 |
May 5, 1994 |
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5669470 |
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Current U.S.
Class: |
191/10 |
Current CPC
Class: |
B60L 2250/16 20130101;
B60L 5/005 20130101; Y02T 10/7027 20130101; B60L 2200/26 20130101;
B60L 53/126 20190201; Y02T 90/121 20130101; B60L 7/14 20130101;
B60L 2270/32 20130101; Y02T 90/125 20130101; Y02T 90/16 20130101;
Y02T 10/7005 20130101; Y02T 90/127 20130101; Y02T 90/14 20130101;
Y02T 90/163 20130101; B60L 53/305 20190201; Y02T 10/725 20130101;
B60L 2210/20 20130101; B60L 50/30 20190201; B60L 53/39 20190201;
Y02T 10/7072 20130101; Y02T 90/122 20130101; B60L 50/51 20190201;
Y02T 10/7033 20130101; Y02T 90/128 20130101; Y02T 10/70 20130101;
B60L 2270/36 20130101; Y02T 90/12 20130101; B60L 53/124 20190201;
Y02T 10/7088 20130101; Y02T 10/72 20130101 |
Class at
Publication: |
191/010 |
International
Class: |
B60L 009/00 |
Claims
1-40. (canceled)
41. A roadway-powered electric vehicle comprising: a vehicle frame
supported by front and rear suspension systems, including front and
rear wheels; an onboard power receiving module mounted on an
underneath side of the vehicle frame that receives electrical power
from a roadway power transmitting module; an onboard energy storage
means for storing and delivering electrical energy; an electric
drive means coupled to at least one of the front or rear suspension
systems for driving the front and rear wheels; and an onboard power
controller means for receiving electrical power from the on-board
power module and directing it to the energy storage means, and for
selectively delivering electrical energy from the energy storage
means to the electric drive means.
42. The roadway-powered electric vehicle as set forth in claim 41
further including modulation means coupled to the onboard power
receiving module for modulating a communications signal onto the
electrical power.
43. The roadway-powered electric vehicle as set forth in claim 42
wherein the communications signal includes information indicative
of the location of the roadway-powered electric vehicle.
43. The roadway-powered electric vehicle as set forth in claim 41
wherein the onboard power controller means includes means for
generating a set of control signals for controlling operation of
the roadway-powered electric vehicle operated, and coupling means
for coupling the set of control signals to a second Roadway-powered
electric vehicle.
44. The roadway-powered electric vehicle as set forth in claim 43
wherein the second roadway-powered electric vehicle includes means
for electronically responding to the set of control signals so that
the second roadway-powered electric vehicle is operated as
controlled by the set of control signals, whereby the second
Roadway-powered electric vehicle follows the Roadway-powered
electric vehicle.
45. The roadway-powered electric vehicle as set forth in claim 43
wherein the second roadway-powered electric vehicle includes: a
regenerative braking system including a second electric drive
system for electromagnetically producing a mechanical resistance
and generating electrical power when braking is applied in response
to the set of control signals.
46. The roadway-powered electric vehicle as set forth in claim 43
wherein the second roadway-powered electric vehicle includes a
frictional braking system for frictionally producing a mechanical
resistance, the frictional braking system including an electronic
actuator responsive to the set of control signals.
47. The roadway-powered electric vehicle as set forth in claim 43
wherein the second roadway-powered electric vehicle includes a
steering system for steering wheels of the second roadway-powered
electric vehicle including an electronic actuator for turning the
wheels of the second roadway-powered electric vehicle in response
to the set of control signals.
48. The roadway-powered electric vehicle as set forth in claim 43
wherein coupling means comprises a flexible cable connected between
the roadway-powered electric vehicle and the second roadway-powered
electric vehicle through which the set of control signals may be
transferred from the roadway-powered electric vehicle to the second
roadway-powered electric vehicle.
49. The roadway-powered electric vehicle as set forth in claim 43
wherein the coupling means includes a transmitter carried onboard
the roadway-powered electric vehicle through which the set of
control signals may be transmitted, and a receiver carried onboard
the second roadway-powered electric vehicle through which the set
of control signals transmitted from the transmitter may be
received.
50. The roadway-powered electric vehicle as set forth in claim 43
wherein the coupling means includes a transmitter carried onboard
the roadway-powered electric vehicle through which the set of
control signals may be transmitted, and a receiver carried onboard
the second roadway-powered electric vehicle through which the set
of control signals transmitted from the transmitter may be
received.
Description
[0001] This application is a continuation of Ser. No. 10/097,531
filed Mar. 12 2002, which is a continuation of Ser. No. 09/538,455
filed May 30, 2000 which is a continuation of application Ser. No.
09/429/835, filed Oct. 29, 1999, which is a Continuation
application of U.S. Ser. No. 09/290,033, filed Apr. 8, 1999, which
is a Continuation application of U.S. Ser. No. 09/126,913, filed
Jul. 30, 1998, which is a Continuation application of U.S. Ser. No.
08/934,477, filed Sep. 19, 1997, which is a Continuation-in-Part
application of U.S. Ser. No. 08/238,990; filed May 5, 1994 for
ROADWAY-POWERED ELECTRIC VEHICLE now U.S. Pat. No. 5,669,470;
Issued Sep. 23 1997, all of which are incorporated herein by
reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to electric vehicles, and more
particularly to an all-electric vehicle system that is powered from
an onboard high-specific-power energy storage device, and that
receives power to charge the energy-storage device inductively
through coils in the roadway over which the vehicle travels. The
invention further relates to enhancements included within such a
roadway-powered electric vehicle system, such as an automatic
position-determining system, automated vehicle guidance,
demand-based vehicle dispatch, and the like.
[0003] In recent years, there has been an increasing emphasis on
the development of an all electric vehicle (EV) or other zero
emission vehicle (ZEV). The goal, as mandated by many governmental
jurisdictions, is to have a certain percentage of all vehicles be
zero-emission vehicles. Advantageously, zero-emission vehicles do
not directly emit any exhaust or other gases into the air, and thus
do no pollute the atmosphere. In contrast, vehicles that rely upon
an internal combustion engine (ICE), in whole or in part, for their
power source are continually fouling the air with their exhaust
emissions. Such fouling is readily seen by the visible "smog" that
hangs over heavily populated urban areas. Zero-emission vehicles
are thus viewed as one way to significantly improve the cleanliness
of the atmosphere.
[0004] In the State of California, for example, the California Air
Resources Board (CARB) has mandated that by 1998 two percent of the
vehicles lighter than 1700 kg sold by each manufacturer in the
state be zero-emission vehicles. This percentage must increase to
five percent by the year 2001, and ten percent by the year
2003.
[0005] A zero-emission vehicle, given the known, viable
technologies for vehicle propulsion, effectively means that such
vehicles must be all electric, or electric vehicles (EV's). Hence,
if existing (and future) governmental mandates are to be met, there
is an urgent need in the art for a viable EV that can operate
efficiently and safely.
[0006] EV's are not new. They have existed in one form or another
since the discovery of electrical batteries and electric motors. In
general, EV's of the prior art are of one of two types: (1) those
that--through rail or overhead wire--are in constant contact with
an external source of electrical power (hereafter
"externally-powered" EV's); or (2) those that store electrical
energy in a battery and then replenish the stored energy when
needed (hereafter "rechargeable battery-driven" EV's).
[0007] Externally-powered EV's require their own power delivery
system, e.g., electrified rails or electrified overhead wires, that
forms an integral part of their own roadway or route network.
Examples of externally powered EV's are subways, overhead trolley
systems, and electric rails (trains). Such externally-powered EV
systems are in widespread use today as public transportation
systems in most large metropolitan areas. However, such systems
typically require their own highly specialized roadway, or
right-of-way, system, as well as the need for an electrical energy
source, such as a continuously electrified rail or overhead wire,
with which the EV remains in constant contact. These requirements
make such systems extremely expensive to acquire, build and
maintain. Moreover, such externally-powered EV systems are not able
to provide the convenience and range of the ICE automobile (which
effectively allows its operator to drive any where there is a
reasonable road on which the ICE vehicle can travel). Hence, while
externally-powered EV systems, such as subway, trolley, and
electric rail systems, have provided (and will continue to provide)
a viable public transportation system, there is still a need in the
art for a zero-emission vehicle (ZEV) system that offers the
flexibility and convenience of the ICE vehicle, and that is able to
take advantage of the vast highway and roadway network already in
existence used by ICE vehicles.
[0008] Rechargeable battery-driven EV's are characterized by having
an electrical energy storage device onboard, e.g., one or more
conventional electrochemical batteries, from which electrical
energy is withdrawn to provide the power to drive the vehicle. When
the energy stored in the batteries is depleted, then the batteries
are recharged with new energy. Electrochemical batteries offer the
advantage of being easily charged (using an appropriate electrical
charging circuit) and readily discharged when powering the vehicle
(also using appropriate electrical circuity) without the need for
complex mechanical drive trains and gearing systems. Unfortunately,
however, such rechargeable battery-driven EV's have not yet proven
to be economically viable nor practical. For most vehicle
applications, such rechargeable battery-driven EV's have not been
able to store sufficient electrical energy to provide the vehicle
with adequate range before needing to be recharged, and/or to allow
the vehicle to travel at safe highway speeds for a sufficiently
long period of time. Disadvantageously, the energy density (i.e.,
the amount of energy that can be stored per unit volume) of
currently-existing electrochemical batteries has been inadequate.
That is, when sufficient electrical storage capacity is provided on
board the vehicle to provide adequate range, the number of
batteries required to provide such storage capacity is
prohibitively large, both in volume and weight. Moreover, when such
batteries need to be recharged, the time required to fully recharge
the batteries is usually a number of hours, not minutes as most
vehicle operators are accustomed to when they stop to refill their
ICE vehicles with fuel. Further, most currently-existing
electrochemical batteries are not suited for numerous, repeated
recharges, because such batteries, after a nominal number of
recharges, must be replaced with new batteries, thereby
significantly adding to the expense of operating the rechargeable
battery-driven EV. It is thus evident that what is needed is a
rechargeable battery-driven EV that has sufficient energy storage
capacity to drive the distances and speeds commonly achieved with
ICE vehicles, as well as the ability to be rapidly recharged within
a matter of minutes, not hours.
[0009] EV systems are known in the art that attempt to combine the
best features of the externally-powered EV systems and the
rechargeable battery-driven EV systems. For example, rather than
use a battery as the energy storage element, it is known in the art
to use a mechanically coupled flywheel, i.e., a flywheel that is
mechanically coupled to vehicle's drive train, that is rapidly
charged up to a fast speed at select locations along a designated
route. See, e.g., U.S. Pat. No. 2,589,453 issued to Storsand, where
there is illustrated an EV that includes a mechanical flywheel that
is recharged via an electrical connection at a charging
station.
[0010] Further, in U.S. Pat. No. 4,331,225, issued to Bolger, there
is shown an EV that has an electrochemical battery as the preferred
storage means, and that receives power from a roadway power supply
via inductive coupling. An onboard power control system then
provides the power to the storage means, and the storage means then
supplies power as needed to an electric motor providing motive
power for the vehicle. Bolger also indicates that the storage means
could be a mechanical flywheel.
[0011] In U.S. Pat. No. 4,388,977, issued to Bader, an electric
drive mechanism for vehicles is disclosed that uses a pair of
electric motors as motive power for the vehicle. A mechanical
flywheel is mechanically connected to the drive shaft of one of the
electric motors. The vehicle receives power from an overhead power
supply, e.g,. trolley lines, and the motor then spools up the
mechanical flywheel. The mechanical flywheel is then used to supply
power to the motor at locations where there is not an overhead
power supply.
[0012] In U.S. Pat. No. 5,224,054, issued to Parry, there is shown
a bus-type vehicle having a continuously variable gear mechanism
that uses a mechanical flywheel as a power source. The mechanical
flywheel is periodically charged by an overhead connection to an
electrical supply. The flywheel is mechanically linked to the drive
shaft of the vehicle.
[0013] In the above systems, the mechanical flywheel is used as the
energy-storage element because it can be charged, i.e., spooled up,
relatively quickly to a sufficiently fast speed. Disadvantageously,
however, the use of such mechanical flywheel significantly
complicates the drive system of the vehicle, and also significantly
adds to the weight of the vehicle, thereby limiting its useful
range between charges. Further, the mechanical flywheel operating
at fast speeds may present a safety hazard. What is needed,
therefore, is an EV that avoids the use of a flywheel mechanically
coupled to the vehicle's drive system. Further, what is needed is
an EV that can receive electrical energy from an external source to
rapidly recharge, within a matter of minutes, an onboard energy
storage element. Moreover, what is needed is such an EV wherein the
onboard energy storage element, once charged or recharged, stores
sufficient energy to provide the motive force needed to safely
drive the vehicle at conventional driving speeds and distances.
SUMMARY OF THE INVENTION
[0014] The present invention addresses the above and other needs by
providing an improved roadway-powered electric vehicle system that
includes: (1) an all-electric vehicle; and (2) a roadway network
over which the vehicle travels. The all-electric vehicle includes
one or more onboard energy storage elements or devices that can be
rapidly charged or energized with energy obtained from an
electrical current. The vehicle further includes an on-board power
controller that extracts energy from the energy storage elements,
as needed, and converts such extracted energy to electrical energy
used to propel the electric vehicle. Advantageously, the energy
storage elements of the vehicle may be charged while the vehicle is
in operation. Such charging occurs, e.g., through a network of
power coupling elements embedded in the roadway. As the vehicle
passes over such power coupling elements, as it traverses the
roadway network, electrical current is coupled to the electric
vehicle, which electrical current is then used to charge the energy
storage devices. Advantageously, such power coupling elements may
be coils embedded at strategic locations in existing roadways and
highways. Such embedding can be done at a very modest cost.
[0015] In a preferred embodiment, the power coupling elements
embedded in the roadway comprise a network of coils connected to a
conventional primary power source, e.g., single-phase, 2000 to 3500
Hz or 8500 to 9000 Hz electrical power generated by a power
conditioner from three-phase 50 or 60 Hz, 480 volt power, as is
readily available from public utility power companies or
cooperatives. Advantageously, such coils need not be distributed
along the entire length of the roadway, but need only be located at
selected locations along the length of the roadway, amounting to,
e.g., 10% or less of the entire length of the roadway, e.g., 1% of
the roadway. A 2000 Hz to 3500 Hz, or 8500 to 9000 Hz alternating
electrical current (ac current) is inductively coupled from the
power coupling elements embedded in the roadway to a power pickup
element carried on the vehicle as the vehicle passes over the power
coupling elements. Such ac current, when received in the power
pickup element on the vehicle, is then used to charge or energize
the storage elements carried by the vehicle.
[0016] A power meter, carried onboard the vehicle, monitors how
much power is transferred to or used by the vehicle. Hence, the
public utility (or other power company) that provides the primary
power to the power coupling elements embedded in the roadway (or
otherwise located to couple power to the vehicle) is able to
account for the electrical power used by the RPEV and to bill the
vehicle owner an appropriate amount for such power, thereby
recouping the cost of generating and delivering such electrical
power.
[0017] In some embodiments, the rapid charge energy storage
elements or devices carried onboard the electric vehicle comprise
an electromechanical battery (EMB), or a group or network of EMB
modules. An EMB is a special type of energy-storage device having a
rotor, mounted for rapid rotation on magnetic bearings in a
vacuum-sealed housing. Because magnetic bearings are used, the
shaft of the rotor does not physically contact any other
components. Hence, there is no friction loss in the bearings.
Because the rotor is housed in a sealed, evacuated, chamber, there
are no loses due to windage. As a result, the rotor--made from
high-strength graphite-fiber/epoxy composite--is able to rotate at
extremely high speeds, e.g., 200,000 rpm. Because the EMB's rotor
is able to rotate at such speeds, high amounts of energy can be
stored in a very compact or small volume representing a significant
improvement in energy density relative to conventional
electrochemical batteries.
[0018] In order to store energy in the EMB, and in order to extract
energy therefrom, a special dipolar array of high-field permanent
magnet material is mounted on the rotor. The resulting magnetic
field from such array, extends outside of the sealed housing to cut
through stationary, external coils, wound external to the housing.
By applying an appropriate ac current to the external coils, the
rotor is forced to spin. Because of the compactness and special
design of the rotor, it is able to achieve high rotational speeds
very rapidly (within minutes). Hence, the EMB may be charged to
store a high amount of energy in a very short time, commensurate
with the same time it takes to fill the gas tank of existing ICE
vehicles.
[0019] Advantageously, the rapid charging EMB does not have any
direct mechanical linkages with the vehicle's drive train. Rather,
the EMB is charged by simply applying an appropriate ac electrical
signal to its terminals. Similarly, the EMB is discharged (energy
is withdrawn therefrom) by simply using it as a generator, i.e.,
connecting its electrical terminals to a suitable load through
which an electrical current may flow. Thus, the complexity of the
charging components and the discharging components is greatly
simplified, and the EMB appears, from an electrical point-of-view,
as a, "battery", having an electrical input and an electrical
output.
[0020] In operation, the input ac voltage applied to the terminals
of the EMB spools up the rotor of the EMB to a rate proportional to
the frequency of the applied ac voltage, just as if the EMB were an
ac motor. The energy stored in the EMB is in the form of kinetic
energy associated with the rapid rotation of the rotor. When
extracting energy, the rapid rotating magnetic field, created by
the rapid rotation of the magnetic array on the rotor, cuts through
the stationary windings, inducing an ac voltage, just as though the
EMB were an ac generator. Such induced voltage thus represents the
extracted energy. The extracted voltage, in turn, is then used, as
needed, to drive the electrical motors that propel the vehicle.
Thus, the EMB functions as a motor/generator depending upon whether
electrical energy is being applied thereto as an input (motor), or
withdrawn therefrom as an output (generator). Unlike a conventional
motor/generator, however, the extremely high rotational speeds of
the EMB rotor allow great amounts of energy to be stored
therein--sufficient energy to provide the motive force for the EV
over substantial distances and at conventional speeds.
[0021] Hence, without any direct mechanical linkage to the
vehicle's drive train, the EMB can be electrically charged (i.e.,
its rotor is spun-up to rapid rotational velocities) using
electrical current that is inductively coupled to the vehicle
through the roadway over which the vehicle travels. Also
without,any direct mechanical linkage, the EMB can be electrically
discharged (i.e., energy is withdrawn from the rapidly spinning
rotor) by having the rotating magnetic field induce a voltage on
the stationary windings, which induced voltage powers the
electrical drive system of the vehicle.
[0022] Advantageously, an EMB may be manufactured as a standardized
EMB module, and several EMB modules may then be connected in
parallel, as required, in order to customize the available energy
that can be stored for use by the EV to the particular application
at hand. For example, a relatively small EV, equivalent in size and
weight to a "sub-compact" or "compact" vehicle as is commonly used
in the ICE art, may require only two to six EMB modules. A larger
or more powerful EV, equivalent in size to a passenger van or high
performance vehicle, may utilize 6 to 10 or more EMB modules. A
still larger and more powerful EV, equivalent, e.g., to a large bus
or truck, may utilize 12-20 or more EMB modules.
[0023] Standardizing the EMB module results in significant savings.
The cost of manufacturing a standard EMB module, as opposed to many
different types of EMB modules, is significantly reduced. Further,
maintenance of the EV is greatly simplified, and the cost of
replacing an EMB within the EV when such replacement is needed is
low.
[0024] Additionally, a high operating efficiency is advantageously
achieved when an EMB is used as the energy storage element. For
example, in an EMB, the entire generator/motor assembly is
ironless. Hence, there are low standby losses (no hysteresis
effects). In combination with the frictionless magnetic bearings
and windless evacuated chamber wherein the rotor spins, this means
that the overall efficiency of the EMB should exceed 90%, and may
be as high as 95% or 96%. Such high efficiencies result in
significantly reduced operating costs of the EV.
[0025] When inductive coupling is used to transfer power from the
power coupling element (e.g., coils) imbedded in the roadway to the
power pickup element (e.g., coils) in the EV, the preferred
coupling frequency of the ac current is in the 2000 to 35000 Hz or
8500 to 9000 Hz ranges. The use of such frequency, significantly
higher than the conventional 60 Hz or 400 Hz ac signals that are
commonly used in the prior art for power coupling purposes,
advantageously optimizes the coupling efficiency of the power
signal and operation of the EV system. Moreover, by using an ac
signal within this frequency range, the magnitude or intensity of
any stray magnetic fields that might otherwise penetrate into the,
vehicle or surrounding areas (as electrical power is inductively
coupled into the vehicle) is significantly reduced. Having the
magnetic fields that penetrate into the vehicle or surrounding
areas be of low magnitude may be an important safety issue, at
least from a public perception point-of-view, as there has been
much debate in recent years concerning the possible harmful effects
of over-exposure to magnetic field radiation. See, e.g., U.S. Pat.
No. 5,068,543.
[0026] It is thus a feature of the present invention to provide an
efficient, viable, safe, roadway-powered all electric vehicle.
[0027] It is an additional feature of the invention, in some
embodiments, to provide such an EV that uses, with only minor
modification, the existing network of highways, roadways,
loading/unloading and/or garaging/parking facilitates that are
already in place to serve ICE vehicles.
[0028] It is yet another feature of the invention, in some
embodiments, to provide an EV system wherein the EV's of the system
may be recharged while such EV's are in operation within the
system. Hence, the EV's need not be taken out of service from the
system in order to be recharged, as is common with prior art
battery-storage type EV's.
[0029] It is an additional feature of the invention, in some
embodiments, to provide an EV, or EV system, wherein the EV uses a
high energy density battery or a group of such batteries as an
onboard energy storage element. In one embodiment, the battery(s)
are electromechanical batteries that due to the use of magnetic
bearings and enclosing the rotor in a sealed vacuum chamber, are
able to run at extremely high speeds (e.g., exceeding 100K-200K
rpm), and thereby provide a large amount of power in a relatively
small space.
[0030] It is a further feature of the invention, in some
embodiments, to provide an EV system that powers a fleet of
electrically-powered buses, or other mass transit electric
vehicles, using a demand responsive charging system or scheme. In
accordance with such scheme, existing highways and roadways over
which the EV's travel are electrified only at select locations,
such as: (1) at designated "stops" of the vehicle, e.g., at
designated passenger loading/unloading zones, parking garages, or
the like; (2) at locations where the vehicle regularly passes, such
as roadway intersections; and/or (3) along selected portions of the
route, e.g., 50-100 meters of every kilometer over which the
vehicle travels.
[0031] It is still another feature of the invention, in some
embodiments, to provide an EV system that uses inductive coupling
to couple electrical power between embedded coils in the roadway
and coils carried in a power pickup element carried onboard the EV.
Such coupled electrical power is stored onboard the EV and is
thereafter used to provide the motive force of the EV. In
accordance with related embodiments of the invention, onboard
systems and methods are provided that laterally and vertically
position the relative spacing and alignment between the onboard
coil and the coils embedded in the roadway in order to minimize the
air gap between the coils and to maximize the alignment between the
coils, thereby making the power transfer from the roadway to the
vehicle more efficient. Moreover, using such onboard systems and
methods, when the EV is stopped, the air gap may advantageously be
minimized to zero.
[0032] It is an additional feature of the invention, in various
embodiments, to provide an EV that utilizes an on-board control
module to perform and coordinate the functions of: (i) receiving
the inductive power from the coils embedded in the roadway, (ii)
storing the received power as energy in the onboard storage
elements, e.g., EMB's, and (iii) selectively extracting the stored
energy to power the vehicle.
[0033] It is yet a further feature, in several embodiments, to
provide an EV that includes an onboard power meter that monitors
the amount of electrical power that has been transferred to the EV
as it operates on the electrified network of highways and roadways,
thereby providing a convenient mechanism for a utility company,
that provides the electrical power to the electrified network of
highways and roadways to recoup its energy costs.
[0034] In addition to the above-identified features, numerous
add-on features may be included as part of the EV system to further
enhance its viability. The add-on features may include, for
example: (a) establishing a wide bandwidth communications channel
with the EV's that permits numerous communications functions (such
as telephone, video, roadway-condition communications, position
information communications, and automated, demand-based dispatch)
to be carried out via the embedded coils over which the vehicle
travels and associated interconnecting power lines, or via a radio
frequency communications link or the like; (b) providing fully
automated garaging features that permit the onboard EMB's (and/or
other storage elements) to be intelligently charged when the
vehicle is parked overnight or at other times in a
specially-equipped garage or parking area; (c) platooning of RPEV's
by producing an electronic (cabled and/or radio frequency) or
optical coupling between a plurality of roadway-powered vehicles,
with one of the vehicles being a "master" or leader, and the others
being "slaves" or followers that follow the master, to provide, in
effect a roadway-powered "train"; (d) using inductive or ohmic
heating coils, powered by the same power source that couples power
into the vehicle from the roadway, to melt snow or ice in the
vicinity of a passenger loading/unloading zone and/or from the
surface of the power coupling element; (e) ergonomically designing
a passenger compartment of the EV to facilitate passenger loading,
unloading, seating, and safety; (f) using an onboard lateral
guidance system to not only position the EV for optimal power
transfer between the power coupling element and the power pickup
element, but to position the EV for elevator-like platform loading
(which can require controlling the position of the EV to within a
few centimeters); (g) providing electronic actuators for steering
and braking so that, when the EV is operating as a "slave" or
follower, reaction time to command signals from the "master" or
leader is minimized; (h) utilizing the wide-band communications
system or the like, in combination with a scheduling and dispatch
computer, for performing dispatch functions and the coordination of
scheduling in a public transportation system based on demand; (i)
precisely determining the position of the EV in response to a
location signal from a global positioning system (GPS) or
Differential GPS (dGPS) receiver, preferably in combination with a
dead-reckoning (i.e., inertial) locating system, in order to (1)
provide a backup position indication for electrically or optically
coupled EV's, (2) provide either primary or backup position
information for lateral alignment of the power pickup element over
the power coupling element and/or for "elevator-like" platform
loading; and (j) wayside control of the EV's through an "ATM-like"
control station for (1) dynamically displaying scheduling
information, (2) summoning free-roaming point-to-point EV's (i.e.,
taxis or limousines), and (3) providing demand-based scheduling
including monitoring the number of passengers on an EV and
adjusting dispatch/scheduling in response thereto; (k) maintaining
communications with the EV during electronic garaging in order to
communicate, e.g., to the vehicle's owner whether the vehicle has
been tampered with; (1) providing a kneeling feature for public
transportation EV's that lowers (or "kneels") the entire vehicle
for loading/unloading, and simultaneously reduces the air gap
between the power pickup element and the power coupling element to
zero or near zero; and (m) providing for route memorization by
recording a dGPS location signal as the vehicle manually driven
over a route so that the vehicle can subsequently automatically
navigate the route.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] The above and other aspects, features and advantages of the
present invention will be more apparent from the following more
particular description thereof, presented in conjunction with the
following drawings wherein:
[0036] FIG. 1 is a block diagram of a roadway-powered electric
vehicle (RPEV) of one embodiment of the invention;
[0037] FIG. 2 is a more detailed block diagram of the RPEV of FIG.
1;
[0038] FIG. 3 is a block diagram of an on-board power director
shown in FIG. 2, and illustrates how an on-board energy storage
system in FIG. 2 is realized using a plurality of electromechanical
battery (EMB) modules or other high-energy-density energy storage
devices;
[0039] FIG. 4 schematically illustrates a roadway-powered EV system
employing a plurality of RPEV's, such as shown in FIG. 1;
[0040] FIGS. 5A and 5B respectively show a cross section, and an
enlarged cross section, of a power coupling element and a power
pickup element suitable for use in the roadway-powered EV system of
FIG. 4;
[0041] FIG. 5C shows a top view of the power coupling element and
the power pickup element of FIGS. 5A and 5B, as used in the RPEV of
FIG. 1, when they are aligned for power transfer;
[0042] FIG. 6A depicts one manner in which only a portion of the
roadways over which the RPEV of FIG. 1 travels need be energized
with roadway power modules;
[0043] FIG. 6B depicts the electrification of the roadway over
which the RPEV of FIG. 1 travels at a multi-lane, signalled
intersection, where vehicles must often come to a complete stop as
they wait their turn to go through the intersection;
[0044] FIG. 6C illustrates electrification of the roadway over
which the RPEV of FIG. 1 travels, with clusters of power coupling
elements being distributed over the length of the roadway;
[0045] FIG. 7 shows one manner in which electronic garaging or
overnight charging may be realized within the RPEV system of FIG.
4;
[0046] FIG. 7A is a block diagram that functionally depicts
electronic garaging features of the embodiment of FIG. 7;
[0047] FIG. 8 depicts a schematic cutaway view of a modular EMB of
a type that may be used with the embodiment of FIG. 1;
[0048] FIG. 9A illustrates an end view of a Halbach array of a type
that may be used with the EMB module of FIG. 8;
[0049] FIG. 9B depicts the calculated field lines for a quadrant of
the Halbach array of FIG. 9A;
[0050] FIG. 10 schematically illustrates various types of
communications channels that may be used with the RPEV system of
FIG. 4;
[0051] FIG. 11 shows a block diagram of communications channel
elements of the embodiment of FIG. 1;
[0052] FIG. 12 depicts one type of time-division multiplex scheme
that may be used by the communications channel elements of FIG. 11
to transfer data from a plurality of sensors;
[0053] FIG. 13 illustrates a schematic diagram of a differential
global positioning system used in combination with an automated
guidance system and a scheduling/dispatch computer to automate the
RPEV system of FIG. 4;
[0054] FIG. 14 illustrates how one or more follower ("slave")
RPEV's may be electronically linked or coupled to a leader
("master") RPEV in order to form a "train" or "platoon" of
RPEV's;
[0055] FIG. 15 schematically illustrates how a power converter used
to electrify heating coils at a passenger loading/unloading zone
and in the surface structure of the power coupling element in order
to prevent the formation of ice or the accumulation of snow in a
passenger area and/or above the power coupling element;
[0056] FIG. 16 is a cutaway view of the passenger compartment of
one embodiment of an ergonomically-designed multiple occupancy
vehicle (MOV) suitable for use as the RPEV of FIG. 1;
[0057] FIG. 17 shows a plan view of the one embodiment of the
passenger compartment in the MOV of FIG. 16; and
[0058] FIG. 18 shows a plan view of another embodiment of the
passenger compartment in the MOV of FIG. 16.
[0059] Corresponding reference characters indicate corresponding
components throughout the several views of the drawings.
DETAILED DESCRIPTION OF THE INVENTION
[0060] The following description is of the best mode presently
contemplated for carrying out the invention. This description is
not to be taken in a limiting sense, but is made merely for the
purpose of describing the general principles of the invention. The
scope of the invention should be determined with reference to the
claims.
[0061] Broadly stated, the invention relates to a roadway-powered
electric vehicle system that includes a network of highways and
roadways that have been electrified at select locations, and a
fleet of roadway-powered electric vehicles (RPEV's) that traverse
the network of highways and roadways and receive their electrical
operating power from the electrified highways and roadways. Many of
the components that make up the RPEV system of the embodiments
described herein are components that already exist and have been
used for other types of EV systems, or other applications. Such
components may be found, for example, and are described in the
following documents, all of which are incorporated herein by
reference: U.S. Pat. No. 4,629,947 (Hammerslag et al.); U.S. Pat.
No. 4,800,328 (Bolger; U.S. Pat. No. 4,836,344 (Bolger); U.S. Pat.
No. 5,207,304 (Lechner et al.); Ziogas, et al., "Analysis and
Design of Forced Commutated Cycloconverter Structures with Improved
Transfer Characteristics," IEEE Trans. Ind. Elec., Vol; IE-33, No.
3, p. 271 et seq. (August 1986); Riezenman, Special Report,
"Electric Vehicles," IEEE Spectrum (November 1992, pp. 18-101;
Post, et al., "A High-Efficiency Electromechanical Battery",
Proceedings of the IEEE, Vol. 81, No. 3, pp. 462-474 (March
1993).
[0062] Referring first to FIG. 1, there is shown a lock diagram of
a roadway-powered electric vehicle (RPEV) 12 made in accordance
with one embodiment of the resent invention. The RPEV 12 includes a
vehicle frame 14 supported by a front suspension system 16,
including front wheels 17, and a rear suspension system 18,
including rear wheels 19. The frame 14 and suspension systems may
be of conventional design. Mounted on the underneath side of the
RPEV 14 is a power pickup element 20 (or onboard power receiving
module). The power pickup element 20 receives electrical power,
symbolically represented by the wavy arrows 22, from a power
coupling element 24 (or roadway power transmitting module) embedded
in a roadway 26 over which the RPEV travels. The roadway power
transmitting module 24 receives power from a power conditioner
circuit 28, which in turn is connected to a utility power
distribution system, such as is provided by a public utility
company. Typically, the utility company provides electrical power
to most customers as 3-phase, 60 Hz power, at 220 vac. Higher
voltages may be made available to some customers, as required, such
as 480 volts ac (vac). The function of the power converter circuit
28 is to convert the 3-phase, 60 Hz power (at whatever voltage is
provided) to an appropriate frequency and voltage for driving the
roadway power transmitting module 24, as described in more detail
below.
[0063] Electrical power received from the electrified roadway 26
(the term "electrified" is used herein to describe a roadway
wherein a roadway power transmitting module 24, or a plurality of
such modules, have been embedded) via the onboard power receiving
module 20 is stored in an onboard energy storage system 30. The
power is directed to such energy storage system 30 through an
onboard power control unit 32 (or onboard power controller).
Advantageously, a power meter 34 monitors all electrical power
received by the onboard power module 20 so that the utility power
company, or other agency, can bill the owner of the RPEV for the
cost of such electrical power.
[0064] A key feature of the present embodiment is performance
achieved from the onboard energy storage system 30, described more
fully below. Such storage system exhibits a very high energy
storage capacity, on the order of 10 to 15 Kw-h. Further, such
energy storage capacity is provided in a very small volume, e.g.,
on the order of from 0.5 to 1 m.sup.3, at an extremely low weight,
thereby providing a very attractive energy density, on the order of
from 20 to 30 kW-h/m.sup.3; a high specific energy, on the order of
150 W-h/kg; and a high specific power, on the order of from 5 to 10
kW/kg. (Note that a conventional electrochemical battery, at best,
can only provide a specific power of about 0.2 to 0.4 kW/kg; and an
internal combustion engine only provides about 0.6 to 0.8
kW/kg.)
[0065] As described more fully below, the preferred element of the
energy storage system 30 is an electromechanical battery (EMB)
because it offers a specific power of up to 10 kW/kg, and offers a
very high efficiency (power out/power in) on the order of 95% or
higher. It is to be understood, however, that the present
embodiment is not limited to the use of an EMB as the energy
storage element. Any storage element which offers the specific
power, efficiency, specific energy and other criteria set forth
herein, may be used with the RPEV system of the present embodiment.
At present, of the available energy storage devices, the EMB
appears to best meet the stated criteria, and therefore it is the
preferred energy storage element. However, it is contemplated that
other high-energy-density energy storage elements, whether such
elements comprise dramatically improved electrochemical batteries,
ultra-capacitors, or other devices, will become available and that
such other high-energy-density energy storage elements may be used
in lieu of, or in combination with, the EMB's described herein.
[0066] The RPEV 12 also includes an electric drive 36 that provides
the motive force for propelling the front and/or rear suspension
systems 16, 18. The onboard power control unit 32, which is
controlled by onboard operator controls 38 and/or automatic control
features programmed into the power control unit 32, selectively
directs electrical power from the energy storage system 30 to the
electric drive 36. The electric drive 36, and operator controls 38,
may incorporate-designs and features as are commonly used in
existing EV's, e.g., battery-powered EV's, or other EV's, as are
known in the art. One such feature common to most EV's, and also
applicable to the RPEV of the present embodiment, is that of
regenerative braking. Regenerative breaking takes kinetic energy
associated with the motion of the vehicle and redirects it back to
the energy storage system 30 rather than having such energy be
dissipated as heat, or in some other form, whenever it is necessary
to brake the vehicle.
[0067] The onboard operator controls 38 are also coupled to a
display panel 39 that provides information to a driver of the
vehicle such as the current state of charge of the energy storage
device 30, vehicle speed, and the like. In addition, the onboard
operator controls 38 are coupled to electronic actuators 38a for
steering and conventional (i.e., frictional) braking of the RPEV
12. Advantageously, the electronic actuators 38a provide much
faster reaction times than achievable through conventional
hydraulic system, and therefore facilitate platooning of multiple
RPEV's and/or automated guidance of the RPEV 12. Use of the
electronic actuators 38a for conventional braking and for steering
is explained more fully below in reference to FIG. 14. The onboard
operator control 38 may also coupled to an rf transceiver system
37, including an antenna that is used to provide a short range rf
communications channel between the RPEV 12 and a wayside control
system, as described more fully below in reference to FIG. 10.
[0068] Thus, as seen in FIG. 1, the RPEV receives its operating
power through the electrified roadway 26, i.e., through the roadway
power transmitting module 24; stores such power in a highly
efficient energy storage system 30; and then uses such stored
energy, as required, to drive the RPEV's electric drive 36.
Advantageously, the RPEV 12 is all electric and has zero
emissions.
[0069] Referring next to FIG. 2, an electrical block diagram of the
RPEV 12 and roadway power module 24 is shown. As seen in FIG. 2,
the onboard power control unit 32 of the RPEV includes a power
director 54, a microprocessor controller 56 and various vehicle
control units 58. As further seen in FIG. 2, the roadway power
transmitting module 24 is simply a coil 40. Such coil 40 is
connected to the power conditioner 28. The preferred power
conditioner 28 is a 3-phase, 60 Hz to 1-phase, f1 kHz converter,
where f1 is a desired coupling frequency. Preferably, the coupling
frequency is from between 2000 Hz and 3500 Hz or between 8500 Hz
and 9000 Hz. Similarly, the preferred onboard power receiving
module 20 is also a coil 42. When a suitable ac electrical current
flows through the coil 40 at the coupling frequency f1, such
current generates a magnetic field that varies at the coupling
frequency f1. Such varying magnetic field cuts through the coil 42
and induces a voltage therein according to Faraday's law of
induction. When the coil 42 is connected to a suitable load, an ac
current is thus established in the coil 42 and power is effectively
coupled from the coil 40 to the coil 42.
[0070] The coupling between the coils 40 and 42 is referred to as
inductive coupling. It is the same type of coupling that occurs in
a transformer, except that in a transformer the two coupled coils
are closely physically coupled and are usually on the same magnetic
core so that the coupling efficiency between the two coils is very
high (i.e., all of the magnetic flux generated by the current in
one coil cuts through the other coil). Where the coupled coils have
an air gap between them, as occurs for this embodiment (with the
coil 40 being embedded in the roadway, and the coil 42 being
carried on the underneath side of the RPEV 12), the coupling
efficiency is a function of the distance, or air gap, between the
two coils 40 and 42, as well as the relative alignment between the
coils.
[0071] In order to improve the coupling efficiency between the
embedded coil 40 and the onboard coil 42, the present embodiment
mounts the coil 42 on an assembly 44. The horizontal position of
the assembly 44 is controlled by a horizontal coil position unit
46. Similarly, the vertical position of the assembly 44 may be
controlled by a vertical (air gap) coil position unit 48. The
vertical position may also, or alternatively, be controlled by an
adjustable ride-height suspension 49 that causes the entire RPEV 12
to "kneel" or lower when it stops to load or unload passengers.
This may be accomplished, for example, through the use of air shock
absorbers, from which air can be released to lower the RPEV 12, or
into which air can be pumped to raise the RPEV. Such kneeling not
only lowers the RPEV's 12 height, thereby easing embarkation and
debarkation, but also significantly reduces the air gap between the
onboard power receiving module 20 and the roadway power
transmitting module 24. Such adjustable ride-height suspension
systems, or "kneeling" suspension systems, are well known in the
automotive and mass transportation arts and are therefore not
described in further detail herein.
[0072] The positioning units 36 and 48, in combination with the
steering of the RPEV 12 and the adjustable ride-height suspension
49, allow the onboard coil 42 to be optimally aligned with the
embedded coil 40 so as to provide the maximum possible coupling
efficiency between the two coils 40, 42. Advantageously when the
RPEV 12 is stopped, for example, e.g., at a passenger
loading/unloading zone, or at a signaled intersection, or when
parked in a parking zone or garage, the air gap between the onboard
coil 42 and the embedded coil 40 may be reduced to zero, or near
zero, by "kneeling" the RPEV 12 and/or lowering the movable
assembly 44 until it contacts the surface of the roadway 26 where
the roadway power, transmitting module 24 is embedded. Such
reduction in the air gap, coupled with optimum lateral alignment of
the assembly 44 relative to the embedded coil 40, allows a maximum
amount of power to be coupled from the embedded coil 40 to the
onboard coil 42. Even when the air gap between the two coils is not
zero, however, as when the RPEV 12 is simply driving over the
electrified roadway, some power is still coupled from the embedded
coil 40 to the onboard coil 42. In order to maximize coupling when
the RPEV 12 is moving, the coils 40, 42 are oriented predominantly
lengthwise (or longitudinally) relative to the RPEV 12. Thus, as
the coils 40, 42 pass over one another maximum coupling is
maintained for a maximum amount of time. Such lengthwise alignment
of the coils 40, 42 is described below in reference to FIG. 5C.
Thus, the RPEV 12 is capable of receiving some power from the
electrified roadway 12 simply by having the RPEV 12 drive over or
on the electrified roadway.
[0073] Two ways of coupling power from the embedded coil 40 to the
onboard coil 42 may be used. First, the embedded coil 40 may be
continuously energized with an appropriate power signal generated
by the power converter 28. Only when the onboard coil 42 comes near
the embedded coil 40, however, is significant power transferred
through the inductive coupling link. This is because the RPEV 12
represents the electrical load that receives the coupled electrical
power. When the load is not present, as when the RPEV is not over
the electrified roadway, then there is nowhere for the electrical
power to go, and no power transfer (or very little power transfer
occurs). This is analogous to having a load, or not having a load,
attached to the secondary winding of a transformer. When the load
is attached, power is transferred to the load through the
transformer. When the load is not attached, no power is transferred
to the secondary winding, and no power (other than the power
associated with magnetic field losses) is transferred.
[0074] A second way of coupling power from the embedded coil 40 to
the onboard coil 42 is to incorporate a vehicle sensor 50 into the
roadway power module 24. The sensor 50 senses the presence of the
RPEV 12, and in response to such sensing, activates the power
converter 28 to energize the embedded coil 40. If the RPEV is not
sensed, then the power converter 28 is not turned on Thus, using
such sensor 50, only when an RPEV 12 is present on the roadway 26
is the roadway 26 electrified. The sensor 50 may be a conventional
vehicle sensor that senses the presence of any vehicle driving on
the roadway, e.g., a pressure switch sensitive to weight, an
inductive strip or loop, or a magnetic or an optical sensor, as are
commonly used in the art to sense vehicles and other large objects.
Alternatively, the sensor 50 may be a "smart" sensor that senses
only RPEV's and not other types of vehicles. A smart sensor is
realized, for example, by incorporating a conventional rf or
optical receiver in the sensor 50 that receives a particular type
of identifying signal (rf or optical) that is broadcast by a
transceiver 52 carried onboard the RPEV 12, or by employing an
optical scanner as part of the roadway sensor 50 that senses or
"reads" a bar code placed on an underneath side of the vehicle as
the vehicle passes thereover.
[0075] Regardless of the manner in which power is inductively
coupled to the RPEV 12 through the coils 40 and 42, an important
consideration for such inductive power transfer is the coupling
frequency (referred to as "f1" above). Such coupling frequency is
the dominant system parameter in the RPEV since the alternating
current is fundamental to the inductive coupling energy transfer
principle, and it affects the size, weight, cost, acoustic noise,
flux density and efficiency of the various energy handling systems.
Further, the coupling frequency interacts with all of the other
system variables in relationships that are generally complex and
non-linear. Coupling frequency is thus a basic parameter that
appears in the specification for every piece of electrical and
electronic apparatus aboard the RPEV 12.
[0076] The importance of the coupling frequency can be further
appreciated by recognizing that heretofore only two standard power
frequencies have existed for several decades, one at 50 or 60 Hz,
which is the universal industrial and household standard, and the
other at 400 Hz, which is an aircraft standard adopted to reduce
size and weight. Neither frequency, however, is optimum for the
RPEV system of the present embodiment.
[0077] The above "standard" frequencies of 50 or 60 Hz or 400 Hz,
termed for purposes of this application to be relatively "low"
frequencies, offer some advantages, particularly in the
transmission of power over transmission lines of substantial
length. For purposes of the RPEV of the present embodiment however,
it has been determined that a "higher" frequency, in the kHz range,
e.g., between 1 and 10 kHz. Between 8500 Hz and 9000 Hz is the most
optimum frequency to use for transferring power through the
inductive coupling link and within the RPEV to-power the RPEV and
to minimize losses. The EMB, while operating at variable
frequencies, operates at a nominal frequency of around 3000 Hz.
Thus, a frequency between 2000 Hz and 3500 Hz may also be
desirable. (Note, if the rotor of the EMB is synchronized with a
3000 Hz driving signal, then it is rotating at 180,000 rpm.)
Further, on the utility side of the energy transfer, i.e., at the
power converter 28, converting the input power from the utility
(typically 3-phase, 480 vac, at 60 Hz) to a single phase signal at
3000 Hz or 9000 Hz can be achieved in a commercially-available
power converter.
[0078] Another important consideration for using an inductive
coupling frequency of around 9000 Hz or 3000 Hz is the strength or
intensity of the stray magnetic fields that might otherwise
penetrate into the RPEV as a result of the electromagnetic fields
associated with the inductive coupling. As indicated above, there
are some safety concerns, or at least perceived safety concerns, at
present regarding whether exposure to such electromagnetic fields
posses a health risk. While there exists no direct evidence
confirming such health risk, many who have studied the issue have
concluded that the prudent thing to do is to avoid exposure to
strong electromagnetic fields. See, e.g., "Electromagnetic Field",
Consumer Reports, pp. 354-359 (May 1994). Advantageously, by using
a coupling frequency of around 9000 Hz or 3000 Hz, the strength of
the magnetic fields within the RPEV is generally less than 1 mG
(milligauss), which is no greater than the background magnetic
fields that are present in a typical U.S. home.
[0079] Still referring to FIG. 2, it is seen that the power
received through the onboard coil 42 is monitored by the power
meter 34. The power meter 34 forms an important part of the present
embodiment because it provides a means for a power utility company,
or other electrical power provider, to monitor power usage and thus
collect payment for the electrical power provided to power the
RPEV. As such, the power meter 34 is preferably mounted so that it
is tamper proof and so that it cannot be bypassed, similar to the
power meters that are installed in most commercial and residential
facilities. Similarly, although not mandatory, it is preferred that
the power meter 34 include means for downloading the power
measurements ("power data") that have been made. As described more
fully below, included on the RPEV 12 is communications system
including, e.g., the transceiver 52, that permits information to be
sent to and from the RPEV 12 from/to a location remote from the
RPEV. Such communications system may, by way of example,
communicate via the power transmitting module 24 and other
sensors/transducers associated therewith or via the RF
communications channel coupled through the onboard operator control
38. When such communications system is used, the power data from
the power meter 34 may be transmitted from the RPEV. Once
downloaded, such power data is preferably directed to the power
utility company. The power utility company is then able to bill the
appropriate owner of the RPEV for the electrical power that has
been used.
[0080] In some configurations, the RPEV 12 includes an
identification data signal that is transmitted from the vehicle
each time that electrical power is coupled thereto when the RPEV is
stopped, and therefore when the assembly 44 has been lowered to
reduce the air gap to near zero. Before electrical power is
transferred, the RPEV identification data signal is verified, and
power data is read from the power meter.
[0081] Another signal that may be transmitted from the vehicle is a
location signal. The location signal is generated by a location
system 59 in response to one or more location determining
subsystems. Such subsystems may include any of a plurality of known
location determining subsystems, such as a Global Positioning
System (GPS) receiver, a Differential Global Positioning System
(dGPS), a LORAN receiver, and/or a dead reckoning or inertial
positioning system, or the like. The location system can be used by
a communications control and monitoring station, described below,
to determining whether the RPEV 12 is properly located, e.g., on
schedule, and can also be used onboard the RPEV 12, in combination
with the microprocessor controller 56 and electronic actuators 38a
to steer the RPEV 12 for optimal positioning over the roadway power
transmitting module 24.
[0082] Advantageously, in addition to steering the RPEV over the
roadway power transmitting module 24, the location signal can be
used by the RPEV 12 to precisely position its doors adjacent to a
loading platform. Such positioning can be accurate to within a few
centimeters when a dGPS receiver in combination with a dead
reckoning system is used to determine position. As a result,
platform loading similar to the loading of a elevator (i.e.,
"elevator-like" platform loading) can be performed, thereby
facilitating access by the disabled, and the elderly.
[0083] Power received through the onboard coil 42 is coupled
through a power director 54 to the onboard energy storage system
30. Also coupled to the power director 54 is the electric drive
train 36. It is the function of the power director 54, as its name
implies, to direct power to and from the onboard energy storage
system 30 and the electric drive train 36. Power is initially
directed, for example, from the onboard coil 42 to the energy
storage system 30. Power is also directed, as required from the
energy storage system 30 to the electric drive train 36.
Regenerative power may also be directed, when available, from the
electric drive train 36 back to the onboard energy storage system
30.
[0084] The power director 54 is controlled by the microprocessor
controller 56. The microprocessor controller 56, which is realized
using a conventional processor-based system, such as the Motorola
68000 series, or the Intel 386/486/PENTIUM series of processors,
both of which are well documented in the art, has appropriate
RAM/ROM memory associated therewith wherein there are stored
numerous operating routines, or programs, that define various tasks
carried out by the microprocessor controller 56. Many such tasks
are the same as are carried out with the operation of any EV. For
purposes of the present embodiment, the most significant tasks
carried out under control of the microprocessor controller 56
relate to directing the power to and from the energy storage system
(explained below in conjunction with FIG. 3), controlling the
lateral and vertical position of the assembly 44 on which the
onboard coil 42 is mounted and the steering of the RPEV 12 to
optimally position the RPEV 12 for power transfer, receiving
appropriate commands from the operator control devices 38, and
monitoring onboard vehicle sensors 60.
[0085] The operator control devices 38 include both operator
control input devices 62 and vehicle displays 64. The input control
devices include, e.g., manual switches or controls that determine
speed, direction, braking, and other controls, associated with the
manual operation or driving of the RPEV. Such devices are of
conventional design and operation. The displays 64 are also of
conventional function and design, indicating to the operator such
parameters as vehicle speed and the status of the energy storage
system 30.
[0086] The operator input control devices 62 generate input signals
to the microprocessor controller 56. The microprocessor controller
56, in turn, responds to such input signals by generating
appropriate output signals that are directed to a set of vehicle
control units 58. The vehicle control units 58 perform the function
of interface (I/F) units that convert the signals output from the
microprocessor controller 56, which are digital-signals, to the
requisite signals for actually effectuating the desired control.
Thus, for example, a braking signal may be sent from the operator
control 62 to the microprocessor controller 56. The microprocessor
controller 56 would process the braking control signal in an
appropriate manner relative to the current status of the RPEV,
e.g., speed, direction, etc., as determined by the vehicle sensors
60, and would determine the appropriate amount of braking needed.
It would then send its output signal to a braking control unit (one
of the control units 58), which would convert it to an appropriate
analog electrical signal. The analog electrical signal is then
directed to an electronically actuated braking mechanism, i.e., a
braking servo motor, that applies the appropriate pressure to the
vehicle's braking system. Similar processes are carried out for
driving the vehicle at a desired speed, steering the vehicle, and
the like with electronic actuators, such as servo motors or stepper
motors, also being preferred for steering of the vehicle.
[0087] Some of the "driving" functions of the RPEV, although often
under manual control of the operator through the operator control
devices 38, may also be automated, or controlled by the
microprocessor controller 56 in accordance with a prescribed or
preprogrammed regime. For example, a key feature of the RPEV of the
present embodiment is to incorporate lateral, as well as vertical
(air gap) positioning of the assembly 44 on which the coil 42 is
mounted. Thus, as the operator of the RPEV approaches, e.g., a
passenger loading/unloading zone, he or she activates an
auto-positioning function that effectively takes over the driving
of the vehicle for the final 10 to 15 feet. Once the
auto-positioning function is activated, the vehicle sensors 60
sense the position of the RPEV 12 relative to the roadway power
transmitting module 24 embedded in the roadway. The steering of the
vehicle is then controlled by the microprocessor controller 56 so
that the vehicle is laterally positioned, to within a rough
tolerance, e.g., .+-.5 to 10 cm, of the optimum lateral position
when the vehicle comes to its designed stopped location. Once
stopped, the horizontal coil positioning unit 46, typically
realized, e.g., using conventional hydraulic and/or electronic
positioning devices, further controls the lateral position of the
coil 42 so that it is more closely aligned, e.g., to within .+-.1-2
cm, of the optimum lateral position. Once the assembly 44 has been
aligned laterally, or concurrent with the lateral alignment of the
assembly 44, the vertical (air gap) positioning unit 48, also
typically realized, e.g., by kneeling the RPEV using the
ride-height adjusting suspension 49, thus reducing the air gap, and
then, using conventional hydraulic and/or electronic positioning
devices to lower the assembly 44 so as to further reduce the air
gap to near zero.
[0088] With the air gap near zero, the onboard energy storage
system 30 is charged with additional power obtained from the power
converter 28 through the inductive coupling link (which operates at
maximum efficiency with a near zero air gap), Before the RPEV is
allowed to move, i.e., before the RPEV can be driven away from the
passenger loading/unloading zone, the vertical positioning unit 48
raises the assembly 44 back to its normal position on the
underneath side of the RPEV frame and the ride-height adjusting
suspension 49 raises the RPEV 12 to a height appropriate for
travel.
[0089] The vehicle sensors 60 comprise a variety of different types
of sensors that sense all of the parameters needed for proper
operation of the RPEV. Such sensors sense, e.g., temperature, lane
position, distance from nearest vehicle or object, and the like.
For purposes of laterally positioning the assembly 44, such sensors
are typically optical sensors that look for markers placed on the
roadway power transmitting module 24 embedded in the roadway. Other
types of sensors may also be used for this purpose, including
acoustic, mechanical, and electromagnetic sensors.
[0090] When the RPEV is traveling (being driven) on an electrified
portion of a highway or roadway, the lateral (horizontal)
positioning device 46 is also activated so that the coil 42 can
maintain, to within a rough tolerance, an optimum lateral position
relative to the coil 40 that is embedded in the roadway. In such
instances, and optionally even when the vehicle is stopped, instead
of using the sensors 60, or in combination with using the sensors
60, to sense the relative lateral location of the coil 42 to the
coil 40, the approximate lateral position may be determined by
monitoring the change in the amplitude of the inductively received
power signal as the coil 42 is laterally moved in one direction or
the other. The microprocessor controller 56 then laterally
positions the coil 42, using the horizontal coil positioning unit
46 and/or the steering of the RPEV, to maintain the coil 42 at a
lateral position that keeps the induced power signal at a peak or
maximum level.
[0091] Turning next to FIG. 3, a block diagram of the onboard power
director 54 and the onboard energy storage system 30 is shown. As
seen in FIG. 3, the preferred onboard energy storage system 30
comprises a plurality of electromechanical battery (EMB) modules,
labeled EMB-1, EMB-2, . . . EMB-n. Each EMB module is constructed
as described below in conjunction with FIGS. 8 and 9A and 9B. The
power director includes a switch matrix 70, a unidirectional
ac-to-ac converter 72, and a bidirectional matrix converter 74. The
bidirectional matrix converter 74 is connected to the electric
drive train 36, which includes one or more ac induction drive
motors 76. The ac-to-ac converter 72 is connected to the onboard
receiving coil 42 through which inductively coupled electrical
power is received.
[0092] Each EMB includes three power terminals, representing the
3-phase signals that are applied thereto (when the EMB is being
charged), or extracted therefrom (when the EMB is acting as an ac
generator). A set of switches, one set for each EMB, connects each
power terminal of each EMB to either the ac-to-ac converter 72
(when electrical power is being applied to the EMB to charge it) or
the matrix converter 74 (when electrical power is being extracted
from the EMB and applied to the induction drive motors 76 that form
part of the electric drive train 36; or when regenerative
electrical power is being applied back to the EMB from the motors
76).
[0093] The unidirectional ac-to-ac converter 72 is of conventional
design. The power signal received through the coil 42 comprises a
single phase, e.g., 3000 Hz signal. This signal is rectified, and
then chopped with an appropriate frequency control signal(s),
provided by the microprocessor controller 58, to create a 3-phase
signal of varying frequency. Each phase of the 3-phase signal thus
generated is applied to the switch matrix 70 so that each phase
may, in turn, be selectively applied to the respective input
terminal of each EMB of the energy storage system. Each EMB is
charged (energy is stored therein) by applying a 3-phase signal
thereto that causes the rotor of the EMB to spin at the frequency
of the applied signal. By applying a 3000 Hz, 3-phase signal, for
example, to the terminals of the EMB, a rotating magnetic field is
established within the EMB that rotates at a rate of 3000
revolutions per second, or 180,000 revolutions per minute (rpm). If
the rotor is stopped when such a signal is applied, then it spools
up to the speed corresponding to the applied frequency,
representing the storage of energy. If the rotor is rotating at a
speed less than the speed corresponding to the applied frequency,
then the rotor speed increases to match the speed dictated by the
applied frequency, representing the storage of additional energy.
If the rotor is rotating at a speed greater than the speed
corresponding to the applied frequency, then the rotor speed
decreases to match the speed dictated by the applied frequency,
representing a decrease in the energy stored in the EMB. Thus, the
key to spooling up, or charging, a given EMB to increase the energy
stored therein is to apply a signal thereto having a frequency
corresponding to a rotor speed that is greater than the present
rotor speed.
[0094] In view of the above, one of the main functions of the
microprocessor controller 56 is to monitor the rotor speeds of each
EMB within the energy storage system 30 so that when an input
signal is received through the onboard coil 42, it can be converted
to a 3-phase signal having an appropriate frequency sufficiently
high so that it will increase the present EMB rotor speed, thereby
storing additional energy in the EMB. To this end, each EMB
includes a means 31 for determining its rotor speed, shown
functionally in FIG. 3 as the speed sensors 31-1, 31-2, . . . 31-n.
Each of the speed sensors 31-1, 31-2, . . . 31-n is coupled to the
microprocessor controller 56 through a suitable bus 33. In
practice, a separate rotor speed sensor is not needed, as the rotor
speed of each EMB may be determined by simply sampling the ac
signal generated by the EMB when operating in a generator mode.
However, in order to emphasize the importance of sensing the EMB
rotor speed (which provides a measure of the energy stored
therein), separate functional speed sensors are shown in FIG.
3.
[0095] The bi-directional matrix converter 74 performs the function
of taking the 3-phase signals generated by each EMB (when
functioning as an energy source, or generator) and converts such
signals as required in order to drive the ac induction motors 76
included in the electric drive train 36. When the RPEV is braking,
or coasting (e.g., going down hill), the matrix converter 74 also
performs the function of taking any energy generated by the motors
(which, when the RPEV is braking or coasting, are really
functioning as generators) and reapplying such energy to the EMB's
of the energy storage system 30. The matrix converter 74 may be as
described, e.g., in Ziogas, et al., "Analysis and Design of Forced
Commutated Cycloconverter Structures with Improved Transfer
Characteristics", IEEE Trans. Ind. Elec. Vol. IE-33, No. 3, 271
(August 1986).
[0096] The switch matrix 70 performs the function of a plurality of
switches that connect the set of power terminals of each EMB to
either the matrix converter 74 or the ac-to-ac converter 72. Such
switch matrix may take various forms, including electrical relays,
solid stake switches, SCR's, diodes, and the like.
[0097] One of the advantages of using the EMB as the basic building
block of the energy storage system 30 is that each individual EMB
may be of a standard size and design. A conventional EMB, for
example, is designed to provide an energy capacity of 1 kW-h. By
using fifteen such EMB modules in parallel, as shown in FIG. 3, the
overall energy capacity thus increases to 15 kW-h. For smaller,
lighter, RPEV's, only a few EMB's are needed to power the vehicle,
e.g., 2-6. For larger, heavier RPEV's, such as trucks and vans,
more EMB's are needed, e.g., 6-10, or more. For even larger RPEV's,
such as buses, further EMB's are added as required, e.g., 12-20, or
more.
[0098] The specifications of a typical RPEV made in accordance with
the present embodiment are as shown in Table 1.
1TABLE 1 Specifications of Typical Roadway-Powered Multiple
Occupancy All Electric Vehicle Item Description UTILITY POWER 480
vac, 60 Hz, 3-phase POWER CONDITIONER Input: 480 vac, 60 Hz,
3-phase Output: 225 kW, 3 or 9 kHz, 1-phase ROADWAY POWER 3 or 9
kHz, 300 amps, 200 kW. TRANSMITTER MODULE Module Length: 3 meters
ONBOARD POWER 3 or 9 kHz, 200 kW; RECEIVING MODULE Mounted on
movable assembly to provide multiple pickup positions ONBOARD POWER
Functions: Motor Controller; CONTROLLER Regeneration Management;
Pickup Power Control; Onboard Energy Storage Control; Monitoring
State of Change; Metering Energy Consumption ONBOARD ENERGY 15 kW-h
(15 1 kW-h modules @ 10 kW STORAGE each, 3 kHz (nominal) ELECTRIC
DRIVE Two 35 kW AC Motors TRAIN MULTIPLE OCCUPANCY 10-15 seated
passengers; 110 km/h VEHICLE (MOV) max speed; low floor; DESIGN
FEATURES platform loading; electric propulsion; electronic
guidance; electronic coupling. ONBOARD CONTROL Functions:
electronic steering; SYSTEM lateral guidance control; electronic
coupling and platform control; vehicle diagnostics; vehicle ID;
"throttle" control; brake control; speed profile control; route
control; vehicle "flight recorder". ROADWAY CONTROL Functions:
roadway-vehicle ELEMENTS communication; lateral guidance signal;
speed markers; vehicle ID interrogation; roadway surface condition
sensors.
[0099] Turning next to FIG. 4, there is shown a schematic
illustration of a roadway-powered electric vehicle (RPEV) system
made in accordance with the present embodiment. The RPEV system
includes a network of, roadways and highways 26, selected portions
of which have been electrified with a roadway power transmitting
module 24, over which a fleet of RPEV's 12 may travel. Each roadway
power transmitting module 24 is connected to a utility power source
over suitable power lines 78, as previously described.
[0100] As indicated above in Table 1, the roadway power
transmitting modules 24 are typically about 3 meters in length. For
many locations of the roadway/highway network, a single module 24
is all that is required in order to efficiently couple to an RPEV
that is above it. At other locations, e.g., along a section where
there is no planned stopping of the RPEV's, such as areas 88 and
90, several modules 24, laid end-to-end, will be needed. Thus, at
parking locations 82, or in an overnight parking garage area 84, or
even at a passenger loading/unloading zone 86, and other locations
where it is anticipated that the RPEV will be stopped for a
sufficient charging time, a single power transmitting module of 3
meter length is all that should be needed. In fact, for a
garage/parking situation, a shortened (e.g., 1-2 meters) power
transmitting module 24' can normally be employed and still provide
adequate coupling with the parked RPEV. Further, at strategic
locations throughout the network of roadways/highways 26, various
sensors 80 may be positioned to provide an indication of roadway
surface conditions. Such information may be transmitted to the
RPEV's 12 through conventional means, e.g., rf transmission; or
through modulation of the power signal transmitted over the primary
power line 78 and inductive coupling link with each vehicle.
[0101] A cross-sectional view of the roadway power transmitting
module 24 is illustrated in FIGS. 5A and 5B, with FIG. 5B showing
an enlarged view of the section of the roadway that is circled in
FIG. 5A. The preferred width of the coils 40 and 42 is about 65 cm,
as seen in FIG. 5B, with the coil being centered in a typical lane
of about 3.65 meters in width, as seen in FIG. 5A. As illustrated
in FIG. 5C, both the embedded coil 40 and the onboard coil 42 may
be characterized as "flat" or "pancake" coils that lie roughly in
respective planes parallel to the surface of the road 26. The coils
40, 42 are elongated lengthwise (or longitudinally) with respect to
the RPEV 12, so as to maximize coupling in cases where the RPEV 12
is in motion as the onboard coil 42 passes over the embedded coil
40.
[0102] With reference to the RPEV system of the present embodiment,
it is noted that a conventional battery-driven electric vehicle is
normally charged overnight for several hours in one's garage, and
then the vehicle starts off the day with a full charge on the
batteries. The rate of charge is inherently constrained by
limitations of power available in the typical household, since 200
KW, if installed, would be prohibitively expensive. The rate of
charge in the home is thus limited to 6 KW to 10 KW, which means
that a typical recharge takes several hours.
[0103] The term "opportunity charging" has been used in the prior
art to signify other times when a stopped vehicle can receive a
charge, for example at curbside or in a parking garage, where it is
stationary and can be plugged in.
[0104] Advantageously, with the RPEV system of the present
embodiment, the idea of opportunity charging takes on a whole new
meaning. In fact, since opportunity charging is so different for
the RPEV system, a new term has been coined, "demand charging" or
"demand responsive charging," to signify the difference. Demand
responsive charging is, as previously explained, made possible by
two technologies: (1) the non-contacting inductive coupling energy
transfer system and (2) an energy storage system that allows a
very-high rate of charge to take place. The combination of these
two technologies and the associated onboard power control unit 32
make it possible to replenish the stored energy of an RPEV in
minutes, not hours.
[0105] At least four types of demand responsive charging are
possible with the RPEV system, described below.
[0106] A first type of demand responsive charging is charging of
electric buses, using inductive coupling pads, at about 25 percent
of its stops. Such charging transfers enough energy for the bus to
run continuously for 24 hours a day, if necessary, since the energy
storage system is being constantly replenished. This means that for
a bus system less than 1 percent of the route would need to be
electrified, contrasted with the trolley bus, which has 100 percent
electrified roadway. From a cost standpoint, this means that a bus
line can be electrified for less than 4 percent of the cost of
overhead wires. It makes a practical electric bus possible for the
first time.
[0107] For the bus, the energy transfer takes place for a 20 second
to 30 second period when the vehicle is fully stopped, thus the air
gap can be zero, or nearly zero, thereby greatly improving the
efficiency as well as the rate of power collection. A
representative electrification of a bus stop along a highway route
is shown at area 86 in FIG. 4. Advantageously, using such demand
responsive charging system for a bus line as described above makes
possible an all-electric bus system that is competitive with a
diesel bus in life cycle costs.
[0108] It should also be noted that in many cases, a bus has
assigned layover points where it must wait for a few minutes in
order to synchronize its route with an advertised schedule. In such
instances, a charging pad 24 may be installed at the layover point,
and the RPEV bus could get enough energy replenishment in 3 to 5
minutes to run much of its assigned loop or route without the need
for further energy transfer.
[0109] A second type of demand responsive charging for use with the
RPEV system of the present embodiment is that of automobile and
highway, and depicted in FIG. 6A. Heretofore, it has been assumed
that an effective electrification system would require the heavily
traveled freeway lanes to be fully electrified, i.e., at least one
lane in each direction for even a thin network in a region. In the
San Diego region, for example, this would mean about 500
lane-kilometers (312 lane miles) would need to be electrified if
one established an electrification network on the freeways.
However, with the RPEV system of the present embodiment, only about
10 percent of the powered lane actually needs power, with the
remaining 90 percent being unpowered, as shown schematically in
FIG. 6A. Hence, when the RPEV travels over the 10% of the lane that
is electrified, it is charged, which charge provides sufficient
energy for it to travel the remaining 90% to the next electrified
location. In practice, of course, a large safety factor is designed
into the RPEV so that it has the capacity, when fully charged, to
travel much further than the 90% distance to the next charging
location. However, the point is that the RPEV receives a charge as
it is traveling over electrified portions of the roadway. From a
system specification standpoint, minimum power transfer rates of
100 to 140 kW in motion, or roughly 30 to 50 KW/m, are desirable.
The onboard energy storage system 30, when realized using a network
of EMB's, advantageously permits this rate of power collection to
take place.
[0110] A variation of the demand responsive charging system shown
in FIG. 6A is depicted in FIG. 6C. In FIG. 6C, the roadway power
transmitting modules 24 (charging pads) are spaced about every 300
m over a distance of, e.g., 1.2 km, and are thus grouped in
clusters 25 of five modules 24 each, with each cluster 25 being
powered from the same power conditioner 28. The clusters 25 are
then selectively spaced along the length of the roadway, e.g., with
a non-electrified section of roadway of about 3.6 km separating the
clustered sections. Thus, for the cluster configuration shown in
FIG. 6C, a new cluster of power transmitting modules 24 is found
about every 4.8 km of the roadway.
[0111] A third type of demand responsive charging for use with the
RPEV system is that of selective electrification of a signalized
arterial intersection, as shown in FIG. 6B. In FIG. 6B, which shows
an aerial view of a typical intersection, the electrified portions
of the intersections, i.e., those that have the roadway power
transmitting modules 24 embedded therein, are shaded. All RPEV's 12
passing through the signalized arterial intersection are able to
take advantage of demand responsive charging. The typical transit
time through the intersection is about 45 seconds to 60 seconds.
During this time, the RPEV receives as much energy from the roadway
module 24 as it could in a mile of a powered lane on the highway.
Thus by electrifying the last 30 meters of a signalized
intersection lane, or lanes, 2% of the arterial lane being
electrified has the same effect as fully electrifying the lane.
[0112] A fourth type of demand responsive charging that may be used
with the RPEV system is that of electric garaging. In electric
garaging, a charging pad 24', approximately 1 meter square and 3 cm
thick, is installed on the surface of a driveway or garage floor,
as shown in FIG. 7. The pad 24', and associated power conditioner
(power supply) 28', are capable of operating in two modes. In a
first electric garaging mode, low levels of continuous energy flow,
e.g., 200 watts to 500 watts, are provided. Such energy flow is
used to provide a stable interior temperature in the RPEV 12 from
about 50.degree. F. to 70.degree. F. corresponding to cold or hot
climates. The RPEV commands the rate of energy flow according to
its need to regulate interior temperatures, and is thermostatically
controlled.
[0113] The energy transfer system for the electronic garaging first
mode is preferably actuated remotely a few minutes in advance of
use to bring interior temperatures to a comfortable level, and a
data link between the roadway and vehicle will provide security
against tampering or theft. The mechanical gap between the vehicle
pickup coil 42 and the roadway element 24' is adjusted to
essentially zero in this mode of operation, as well as in the
static charging mode described next.
[0114] In a second electronic garaging mode, the pad 24' is used
for an overnight recharging of the energy storage system 30 of the
RPEV 12. In this case the power flow levels are between 6 KW and 10
KW (comparable to an electric clothes dryer in a residence), and
the time for recharge ranges from 1 hour to 2 hours.
[0115] Preferably, the electronic garaging operates in a demand
responsive mode, and is fully automated and hands-off for the
driver. The RPEV generates an enabling signal to carry out the
charging at times of day when utility rates are lowest, e.g., at
2:00 a.m., turning it off when the energy storage is
replenished.
[0116] The circuitry needed to accomplish the two modes of
automatic garaging described above is further depicted in FIG. 7A.
A pressure sensor 162 senses the presence of a vehicle 12' parked
above the charging pad 24'. A receive coil 164 (which may function
as the sensor 50 (FIG. 2) may further be used to verify the
identity of the vehicle 12'. A charging control circuit 166
controls when the power-conditioner 28' is allowed to charge the
charging pad 24' and at what charging level. To this end, a clock
circuit 168 provides an indication to the control circuit 166 of
the time of day so that the high level charging mode can occur when
the electric rates are the lowest. In like manner, a communications
receiver 170 is attached to the control circuit 166 so that the low
level charging mode (used, e.g., to bring the interior of the
vehicle 12' to a comfortable temperature) may be invoked on
command. The owner of the garaged vehicle, for example, may invoke
the low level charging mode using a remote transmitter, similar to
a garage door opener transmitter; or by throwing a remote switch
that is electrically coupled to the receiver 170.
[0117] The RPEV, as previously described, may issue an enabling
signal through the above-mentioned radio frequency communications
channel to command the energy transfer to take place, depending on
the energy storage requirements at that moment. A high rate of
energy transfer for a short period is preferred, if possible. But
regardless of whether the transfer is for a short period of time,
as at an intersection or bus stop, or for a longer period of time,
as at a parking stall or garage, the system is charged only as
needed and as requested or demanded, hence the term "demand
responsive charging" properly describes the charging action that
takes place.
[0118] Referring next to FIG. 8, a schematic cutaway view of a
modular EMB 31 of a type that may be used with the present
embodiment is illustrated. An EMB module 31 of the type shown in
FIG. 8 is described more thoroughly in Post et al.,
"High-Efficiency Electromechanical Battery,", Proceedings of the
IEEE, Vol. 81, No. 3, pp. 462-474 (March 1993). Basically, the EMB
module 31 includes a rotor 103 mounted for rotation on magnetic
bearings 100 and 102 within a sealed vacuum chamber 97. The sealed
vacuum chamber 97 is defined by thin stainless steel walls 94,
reinforced with fiber composite, and a glass ceramic sleeve 95. The
entire vacuum chamber 97 is then mounted inside of a containment
vessel 92 made of highly impact-resistant material, such as
three-dimensional fiber composite. Appropriate gimbal mounts 98
(represented as springs) are used to mount the vacuum chamber 97
within the vessel 92. Three-phase, stationary, generator windings
96 are mounted outside of the vacuum chamber 97, between the thin
walls 95 that define a narrow neck portion of the vacuum chamber.
Each winding terminates at one of three terminals 99.
[0119] The rotor 103 is made from concentric rotating cylinders
104, 106, 108 and 110. The concentric rotating cylinders are made
from thin walls (10% of the radius) to prevent delamination, and
are separated by an elastic material 109. A magnet array 111 is
placed on the inside of the inner concentric rotor cylinder 110 to
create a rotating dipole magnetic field. The rotor 103 rotates at a
velocity of the order to 10,000 rads/s (i.e., about 3,000 rot/s),
and allows each EMB module to produce about 1 kW-h of energy.
[0120] Advantageously, the EMB module 31 stores more energy per
unit mass or per unit volume than other known energy devices. This
is because stored energy increases only linearly with the mass of
the rotor (for a given geometry), but goes up as the square of its
rotation speed. Since the rotor 103 is made of a light, strong
material, it can be spun much faster than a heavy strong material
(commonly used in conventional mechanical flywheels) before
centrifugal forces threaten to break it up. The result is that the
EMB can store much more energy, and more safely, than has
previously been possible.
[0121] Composite materials based on graphite make it possible to
build the EMB with a specific energy of about 150 Wh/kg, and a
specific power that is orders of magnitude greater than anything
achievable by an electrochemical battery or even an internal
combustion engine. As indicated previously, the EMB can deliver a
specific power of 5,000 to 10,000 W/kg.
[0122] To keep the EMB from running down, the rotor 103, as
indicated, runs on magnetic bearings 100 and 102 in the vacuum
chamber 97, realized, e.g., using permanent magnets made from
Nd--Fe--B. Such bearings offer the added advantage of extending the
EMB's life since there is no mechanical contact, and hence no wear,
with this mode of suspension. As a result, the sealed EMB, has an
extremely long lifetime, and should outlast the vehicle in which it
is carried.
[0123] The vacuum chamber 97 is evacuated to a pressure of
10.sup.-3 to 10.sup.-4 pascals. To achieve and maintain a vacuum of
that pressure, it is important that the rotor materials minimize
vacuum outgassing, and that other materials employ modern getter
alloys.
[0124] In order to assure safety, which is always a concern any
time a great deal of energy is stored in a small volume, the rotor
materials are selected and designed to fail by disintegrating into
a mass of fairly benign fluff or "cotton candy". In contrast,
massive steel rotors, such as are used in mechanical flywheels, may
fail in a spectacular fashion, throwing off large chunks of
shrapnel. The vessel 92, also made of a three--dimensional
composite, is able to readily contain any such disintegrating mass
by incorporating into its design high-strength fibers that run in
all three directions. With such construction, any cracks that get
started in the housing are not able to propagate.
[0125] Advantageously, the EMB is ironless. This feature not only
keeps the weight low, but prevents hysteresis losses common in iron
systems. Moreover, since inductances of the multi-phase windings
are extremely low (with no iron present), and since rotation speeds
are high, unusually high peak power outputs are achievable, with
stator copper losses that can readily be handled by conventional
means (air or liquid cooling).
[0126] A central feature of the EMB is the generator/motor design.
A special array of permanent magnet bars 112 is mounted on the
rotor at 109 (FIG. 8). An end view of such array, known as the
Halbach array, is shown in FIG. 9A, with the arrows indicating the
relative polarity of the bar magnets 112. The magnetic lines of
force associated with one quadrant of such array are shown in FIG.
9B. Of significance is the uniformity of the interior field, and
its near cancellation outside of the array. Using Nd--Fe--B
magnets, having a B equal to 1.25 Tesla, dipole fields of the order
0.5 T can be readily obtained.
[0127] A typical EMB module of the type shown in FIGS. 8, 9A and
9B, provides the following operating parameters:
2 Rotation speed: 200,000 rpm Magnetic field of Halbach Array: 0.5
T Length & Width of windings: 0.8 m .times. .04 m Number of
turns: 10 Output voltage (3-phase): 240 V rms
[0128] It is to be emphasized that the EMB is the preferred
energy-storage device for use with the RPEV of the present
embodiment because the EMB offers specific power and specific
energy that makes it a viable energy source for an electric
vehicle. As other alternative energy sources or energy storage
devices are developed, offering the same or similar performance
relative to their specific power and specific energy, such
alternative energy sources may also be used with the present
embodiment.
[0129] Referring next to FIG. 10, the communications channel
provided as part of the RPEV system will be described. It is noted
that several different types of communications channels are
illustrated in FIG. 10, any one, or any combination of which, may
be used with the present embodiment. Hence, not all of the elements
shown in FIG. 10 are needed for a given type of communications
channel, but all such elements are nonetheless shown in FIG. 10 in
order to reduce the number of figures that might otherwise be
needed.
[0130] A first type of communications channel useable with the
present embodiment is used to broadcast roadway conditions to the
RPEV before the RPEV encounters such conditions. Such an early
roadway-condition warning system includes a plurality of roadway
sensors 80 that are selectively positioned along the roadway 26,
e.g., at the same locations where the charging pads 24 (also
referred to as the roadway power transmission modules) are located.
Typically, such roadway sensors will be located at least 300 m
apart, and may be much farther apart, e.g., 1 to 5 km. The roadway
sensors 80 detect the condition of the surface of the roadway 26,
and other environmental parameters of interest. Typically, the
sensors 80 sense at least whether there is any moisture or ice on
the roadway surface, and may also sense the temperature of the
roadway surface.
[0131] Each roadway sensor 80 is connected to an appropriate sensor
driver circuit 122 that provides the sensor with whatever
electrical signals it needs to perform its sensing function. For a
moisture/temperature detector, such signals typically include just
a current pulse of a few ma. The sensor driver circuit 122, after
determining the measured parameter, encodes this information to
create a sensor signal, or sensor word. The sensor word, in
addition to the measurement of the moisture/temperature, also
includes an identification number to identify the particular sensor
80 from which the sensor signal originated. Alternatively, the
sensor signal may be transmitted in a time-division multiplex
scheme that uniquely identifies the sensor from which it
originated. The sensor word is provided to a transceiver (xcvr)
circuit 122. The roadway sensor 80 and corresponding sensor drive
circuit 122 are of conventional design.
[0132] The transceiver circuit 124, for this application, functions
as a transmitter and provides the sensor word to a power
modulator/demodulator circuit 126. The power modulator/demodulator
circuit 126 is coupled to the main power line 130 that provides the
primary power to the power conditioners 28 and to the output of the
power conditioner (PC) 28 that provides the 1-phase, 3000 Hz
(nominal), signal to the charging pad 24. The information signal is
superimposed with the power signal on the power line, or is
otherwise merged with the power signal, so that the power line
conductor passes both the information signal and the power signal.
The manner of superimposing an information signal on a power
signal, or modulating a power signal with an information signal, is
known in the art. (See e.g., the security system art, where the ac
power lines of a protected structure are also used to interconnect
individual sensors with a central monitoring device.)
[0133] The main power line 130 thus functions as the medium, or
communications channel, through which sensor signals may be
transmitted from one power modulator/demodulator 126 to another.
Each power modulator/demodulator 126 further couples the signals
stripped off of the main power line to the respective charging pads
so that such signals may be coupled into each RPEV as it travels
over the respective pad 24. Moreover, as seen in FIG. 10, an
additional power modulator/demodulator circuit 132, and a
corresponding transceiver circuit 134, couple the sensor signals,
and any other signals that may be on the communications channel
(the main power line 130) to a communications control and
monitoring station 136 (or communications center). The
communications center 136 thus functions as a communications center
for the RPEV system.
[0134] The RPEV 12, upon being charged with a power signal through
the charging pad, also receives the sensor signals from the various
sensors along the roadway 26. Once received, the sensor signals are
processed (using the onboard processor 56) and acted upon.
Typically, the information contained within a sensor signal is at
least displayed, e.g., "sensor No. xx, located at point yy on the
roadway, reports ice and/or moisture," and may also be factored
into any automatic controls that may come into play when that
portion of the highway is reached.
[0135] An additional type of communications channel that may be
used with the present embodiment is as described above, but further
uses an existing or dedicated communications line 138 to tie the
various transceiver circuits 124 together and to the communications
control and monitoring station 136. Existing communications lines
138 that may be used as the line 138 include land-based telephone
lines, cellular telephone channels, cable TV lines, and the like.
Also for many applications of the RPEV system, where a relatively
small area is serviced by the RPEV's, a dedicated coax
communications line, installed between each power transceiver unit
124, would be economically viable to serve the function of the
communications line 138.
[0136] Still referring to FIG. 10, a further type of communications
channel may be established by embedding into the roadway 26 a wire
loop 140 that effectively serves as an antenna to couple signals to
the RPEV 12 at all locations along the roadway where the charging
pads 24 are not located, e.g., at all non-electrified roadway
sections. (At electrified locations, signals may be coupled to the
RPEV through the charging pads, as described above.) Such loops 140
may be coupled to the same input power lines that charge the
respective charging pads. In those locations where there is not a
charging pad, e.g., where the wire loop is some distance from a
charging pad, a separate transceiver 124' may be connected directly
to the wire loop 140. Such transceiver 124' is then coupled to a
power modulator/demodulator circuit 126' (when used), or to the
communications line 138.
[0137] In operation, the availability of the wire loop 140 allows
continuous communications to be had with the RPEV regardless of
where it may be located along the network of roadways and highways.
Hence, telephone, video and other signals may be readily accessible
within the RPEV as it travels along a route having the wire loop
140.
[0138] The wire loop 140 may be installed or embedded within the
roadway 26 without great expense. In most instances, all that is
required is to grind, cut, or etch a small groove or channel in the
roadway surface, lay down a suitable conductor within the groove or
surface, and cover or seal the groove or channel with tar,
pavement, or other suitable filler.
[0139] As a further type of communications channel, the RPEV 12 may
also carry onboard a conventional rf transceiver 142 (which may
serve as the transceiver 59 in FIG. 2) that, through a suitable
antenna 144, is in telecommunicative contact with the
communications control and monitoring station 136, which also has
an antenna 146. Such rf telecommunications channels are well known
and used in the art, but potentially suffer from degraded reception
and transmission in areas where there are mountains, buildings, or
other structures or obstacles that interfere with the rf
channel.
[0140] Other types of communications channels and transportation
features that may be used with the RPEV system of the present
embodiment are as described, e.g., in "Transportation", IEEE
Spectrum, pp. 68-71 (January 1993), incorporated herein by
reference.
[0141] Regardless of the type of communications channel that is
employed, it is important to note that such communications channel,
or channels, may be used to both send and receive information to
and from the RPEV. Thus, for example, a particular RPEV may
periodically send an identification signal that identifies that
RPEV, and the location whereat the signal is received along the
communications channel thus provides a way for the communications
center 136 to "track" the RPEV. In addition, the RPEV may send the
location signal that indicates the exact location of the RPEV, as
described above, further refining "tracking" capabilities of the
communications center 136. Such "tracking" capability is of
significant benefit for fleet management purposes, and in
particular for automated scheduling and dispatch of public
transportation RPEV's, as described below in reference to FIG. 13.
Further, with the ability to send signals to and receive signals
from the RPEV, it is possible to completely control its operation
from the communications center 136, thereby obviating the need to
have a driver onboard the RPEV where the RPEV's are used, e.g., as
a public transit type of system, or as a cargo delivery system.
[0142] Referring to FIG. 11, a functional block diagram is shown of
one manner in which the communications channel interface with the
RPEV 12 may be realized. Many of the elements shown in FIG. 11 are
the same as those of FIG. 2, although many of the elements of FIG.
2 have been omitted from FIG. 11 for clarity. In FIG. 11, the
embedded coil 40 and the onboard coil 42 are shown, as has been
previously described. The embedded coil 40 inductively couples the
1-phase power signal to the onboard coil 42. Such power signal may
be modulated with the information signal that is to be transferred
to the RPEV 12. Thus, when the power signal is received within the
RPEV, the information signal is demodulated (stripped away from the
power signal) using an onboard modulator/demodulator circuit 150,
and then processed as needed (e.g., converted to an appropriate
form) by a receiver circuit 152, and presented to the
microprocessor controller 56. In some embodiments, by way of
example, the information signal may include a command signal that
is used to control the electronic actuators responsible for
steering and braking. Thus, as described above, an information
signal may be sent to the RPEV.
[0143] When an information signal is to be received from the RPEV,
i.e., transmitted by the RPEV, such signal originates in the
microprocessor controller 56 and is presented to an appropriate
onboard transmitter circuit 154, which may be of conventional
design, that converts the signal to an appropriate form for
transmission. The signal is then presented to the onboard
modulator/demodulator circuit 150, where it is modulated in an
appropriate manner and presented to a transmit coil 43. The
transmit coil 43 inductively couples the signal to a receive coil
41, which then presents the signal to communications receiver 124.
The communications receiver 124 then couples the signal directly to
the communications line 138, or to the power modulator/demodulator
126, which couples it to the main power line 130.
[0144] While a separate embedded coil 40 and receive coil 41 are
shown in FIG. 11 to perform the sending and receiving functions,
respectively, at the embedded location, and a corresponding
separate transmit coil 43 and onboard coil 44 are shown that
perform the sending coils 40, 41 may be the same coil, as may the
coils 43, 44.
[0145] FIG. 12 illustrates one manner in which the sensor signals,
obtained from all the various roadway sensors 80 that may be
located along the length of the roadway 26, and other signals
transmitted to and from the RPEV over the communications channel,
are multiplexed so that the signals are not confused and
intermingled with each other. For example, with respect to the
roadway sensor signals, it is important that a given RPEV be able
to determine which sensor signal originated with which sensor (and
hence from which roadway location the sensor signal originates).
The multiplex scheme depicted in FIG. 12 is that of a time division
multiplex scheme. In accordance with such scheme, all that is
required to perform the multiplexing function is to assign a
specific time when a certain identified signal is to be sent or
received. Such time division is easily accomplished simply by
counting cycles of the power signal. As seen in FIG. 12, a
synchronization pulse 160 is generated by the utility company, or
otherwise superimposed on the main power signal, every second.
Hence, for a power signal that operates at a frequency of 60 Hz,
there are exactly 60 cycles of the ac power signal between sync
pulses, each cycle having a duration of 16.7 msec. Each of these
cycles is assigned a certain function depending upon its location
relative to the sync pulse 160. Thus, for example, the odd cycles
following the sync pulse, i.e., the 1st, 3d, 5th, 7th, . . . cycles
are assigned for transmission; and the even cycles following the
sync pulse, i.e., the 2nd, 4th, 6th, 8th, . . . cycles are assigned
for receiving. The first 12 cycles may be reserved for general
communications functions in this manner. The remaining 48 cycles
may be assigned to 48 respective sensors, with a first sensor (at a
first known location on the roadway) inserting (superimposing) its
sensor signal on the power signal during the 13th power cycle, a
second sensor (at a second known location on the roadway) inserting
its sensor signal on the power signal during the 14th power cycle,
and so on. If there are more than 48 sensors to be monitored, then
the multiplexing capacity may be increased by either increasing the
duration between the sync pulses, e.g., to 2 sec., and/or counting
half cycles of the power signal instead of full cycles.
[0146] Referring to FIG. 13, a schematic diagram is shown of a
differential global positioning system (dGPS) used in combination
with an automated guidance system and a scheduling and dispatch
computer to automate the RPEV system. The RPEV 12 (FIG. 1) is shown
at two locations around a public transit route 250. Each of the
RPEV's receives signals from each of at least three earth orbit
satellites 252, 254, 256, and from a differential ground
transmitter 258. Using known processing techniques, first, second
and third position signals 260, 262, 264 received by the RPEV's
from each of the satellites 252, 254, 256, respectively, are
processed within the dGPS receiver 59 (FIG. 2) in order to
determine the approximate location of the respective RPEV's. A
differential position signal 266 is also processed by the dGPS
receiver 59 using known techniques to precisely, i.e., within
several centimeters, determine the location of the RPEV 12. As a
protection against momentary loss of any of the position signals
260, 262, 264, 266, a dead reckoning system is also part of the
dGPS receiver. The dead reckoning system operates in accordance
with well known inertial positing technology, and therefore further
explanation of the dead reckoning system is not made herein. In
response to this precise determination of the RPEV's position
(based on differential GPS in combination with inertial position
determination), the location signal is generated by the dGPS
receiver 59, and is passed to the microprocessor 56 (FIG. 2).
[0147] The location signal, in some embodiments, is used by the
microprocessor 56 to determine a course error, which represents the
difference in location of the RPEV as compared to a desired
position. The desired position is time indexed and stored in the
memory associated with the microprocessor, such that the
microprocessor is able to determine a desired position of the RPEV
based on the time of day. Once, the course error is determined, the
microprocessor determines appropriate course and speed corrections
and controls the electric drive 36 (FIG. 1) and/or the electronic
actuators 38a (FIG. 1) to carry out such course and speed
corrections. A human operator is also preferably on board to make
course corrections in the event for some reason it becomes
necessary to deviate from the desired position (such as might occur
when pedestrians step in from of the RPEV).
[0148] In order to generate the time-indexed desired positions, the
RPEV is manually driven over the route 250 while in a learn mode.
In the learn mode, the location signal generated by the dGPS
receiver is recorded in the memory, providing a record of a desired
course and speed. In this way a desired course and speed for the
RPEV can easily be established without the need for programming or
other complex setup operations.
[0149] The location signal, in addition to possibly being used by
the microprocessor to determine course and speed corrections can be
transmitted by the transceiver (FIG. 2) to a transceiver 268
coupled to a scheduling and dispatch computer 270. The scheduling
and dispatch computer 270 is coupled to a plurality of "ATM-like"
terminals 272, which display the locations and estimated arrival
times of the RPEV's at various passenger loading/unloading areas
274 at which the "ATM-like" terminals 272 are installed.
[0150] One or more of the "ATM-like" terminals 272' may be
installed at a passenger loading/unloading area 274' to which the
RPEV's are not normally scheduled. When a passenger desires to be
picked up at such a passenger loading/unloading area 274', they
indicate this desire to the scheduling and dispatch computer 270
via the "ATM-like" terminal 272'. Upon receiving this indication,
the scheduling and dispatch computer determines which of the RPEV's
to send to pick up the passenger, and redirects such RPEV to the
passenger. In this way, an RPEV can be summoned to the passenger
loading/unloading area 274' not normally serviced, and the
scheduling and dispatch computer 270 can dispatch an RPEV to
respond to the summon. The dispatching of the RPEV is effected by
the scheduling and dispatch computer 270 transmitting a rerouting
signal to the RPEV to be dispatched to pick up the passenger.
[0151] In a slight variation of this feature, the "ATM-like"
terminals 272 can be used to summon free-roaming taxi or
limousine-like RPEV's. The taxi or limousine RPEV's do not operate
on a route per se, but are operated on a point-to-point basis.
While automated navigation is possible, just as with the public
transit-type RPEV's described above, the passenger
loading/unloading area 274' at which the passenger is picked up and
the passenger loading/unloading area 274 at which the passenger is
dropped off are determined by the passenger, as opposed to a
prescribed route. In addition, the taxi or limousine-type RPEV,
generally, will not make a stop to pick up other passengers until
it has delivered its passenger to their destination passenger
loading/unloading area 274.
[0152] In accordance with another feature of the present
embodiment, when passenger load is unusually high, passengers can
indicate that they were not accommodated by the last RPEV to stop
at a particular passenger loading/unloading area by pressing one or
more buttons on the "ATM-like" terminal (or via other input means,
such as a touch screen). As the number of passengers not
accommodated increases, the scheduling and dispatch computer 270
can alter the RPEVs' schedules and increase the number of RPEV's
servicing the route 250. These schedule alterations are displayed
on all of the "ATM-like" terminals so that passengers continue to
know when they can expect the next RPEV at their particular
passenger loading/unloading area.
[0153] As in the RPEV system of FIG. 4, as the RPEV's execute the
route 250, either automatically or under the control of a driver,
they may move over one or more embedded coils 24 embedded along the
route 250, and/or one or more embedded coils 24 located in
passenger loading/unloading areas. These embedded coils 24 provide
power to the energy storage devices within the RPEV's as explained
hereinabove. The embedded coils 24 are coupled to the power
conditioners 28, which are coupled to utility power, as described
above.
[0154] In this way, RPEV's are able to automatically guide
themselves over a prescribed route, while having their energy
storage devices recharged at various points along the route. In
addition, the dispatch of RPEV's to not normally scheduled
passenger loading/unloading areas, and automatic modification of
the RPEVs' schedule is performed based on passenger load.
Advantageously, modifications to the RPEVs' schedules are displayed
using the "ATM-like" terminals, so that waiting passengers always
know when they can expect the next RPEV at their passenger
loading/unloading area.
[0155] Referring next to FIG. 14, the concept of electronically
linking a plurality of RPEV's together in order to form a "train"
of such vehicles is illustrated. Advantageously, the RPEV may be
totally controlled electronically, as a robot, because its controls
are all amenable to simple commands, e.g., drive forward at a
certain speed, steer left or right, brake, etc. Nonetheless,
because the RPEV is constantly in traffic, and not all
circumstances can be foreseen, it is usually desirable to have a
real person onboard that can operate the vehicle, even though such
person may, on occasion, place the vehicle in an "auto pilot" mode.
Hence, by electronically linking more than one RPEV together, a
lead RPEV, termed the "master", on which a live person operator is
located, may generate the electronic signals that are used to
control one or more following RPEV's, termed the "slave".
[0156] The master/slave RPEV system is depicted in FIG. 14. In the
bottom portion of FIG. 14, a master RPEV 172 leads two slave RPEV's
174 and 176. The coupling of the electronic control signals from
the master 172 to the slaves 174 and 176 is by way of a flexible,
coiled cable 178 that simply plugs into both RPEV's. Such cable
bears no mechanical tension as each RPEV has its own source of
power, and is independently charged through the network of charging
pads 24.
[0157] As shown in the top portion of FIG. 14, a master RPEV 180
leads a slave RPEV 182 with the electronic coupling being provided
by a flexible, coiled cable 178, as previously described, and/or
with an rf link, represented in the figure by the antennas 184 and
wavy arrow 186. The rf link is used to provide an alternative or a
redundant link (when used redundantly used to provide added safety)
through which the proper command signals may be received by the
slave vehicle. As an alternative, or in addition to the rf link, an
infrared communications channel may also be provided. When an
infrared communications link is used, each of the RPEV's are fitted
with an IR transmitter and each with an IR receiver. The IR
transmitter on the "master" is used to communicate the command
signals to the IR receiver on the "slave" and the IR transmitter on
the "slave" is used to communicate feed back signals to the IR
receiver or the "master".
[0158] The location signals generated by the dGPS receivers aboard
the RPEV's are used as a backup to the cable, rf and/or ir links
between the "master" and the "slaves" to assure than the "slaves"
maintain proper positions relative to the "master." As the "slaves"
deviate from proper positions behind the "master," course and speed
corrections are automatically computed and executed by the
"slaves."
[0159] Turning next to FIG. 15, a further enhancement of the RPEV
system of the present embodiment is schematically depicted. In FIG.
15, the charging pad 24 is located at a curbside designed for a
passenger loading/unloading zone, and with the charging pad 24. The
charging pad 24 is powered from a power conditioner 28 as
previously described. Also powered by the power conditioner 28 are
heating coil pads 188. The heating coil pads 188 are embedded in
the sidewalk, or other surface material, that surrounds the
passenger loading/unloading zone. The purpose of the heating coil
pads 188 is simply to melt any ice or snow that might otherwise
accumulate at the loading/unloading zone, thereby providing a
further convenience and measure of safety for the passengers, and
any ice or snow that might otherwise accumulate on the charging pad
20, thus presenting the reduction of the air gap to zero. The
heating coils 188 are not heavy consumers of electrical power, but
operate using only about 200-400 W each. Thermostatic control of
the heater coils may be used to maintain the surface temperature
around the coils to within a desirable range.
[0160] A further important feature achievable with the RPEV system
of the present embodiment is the ergonomic design of the passenger
compartment of a multiple occupancy vehicle (MOV) that includes the
RPEV features previously described. An MOV 13 is shown, partially
cutaway, in FIG. 16. The MOV 13 is a unique, low-floor
automobile-sized vehicle. That which is shown in FIG. 16 is for an
all-seated version for 15-17 passengers, plus an operator. The plan
view of one seating arrangement for such MOV is shown in FIG. 17
and a plan view of another seating arrangement is shown in FIG. 18.
A standing version of the MOV may also be used. The MOV is adapted
for traveling on the electrified roadway described herein. It is
charged at stops using a demand responsive charging mode, also as
previously described. It is an all electric vehicle, and utilizes
electronic guidance at pullouts to assure good alignment between
the coupling coils. It may be coupled electronically with other
vehicles, as described in connection with FIG. 14 above.
[0161] The MOV 13 has a door system that allows easy ingress and
egress with sufficient head room to avoid bumping one's head. For
example, as seen in FIG. 16, the door system includes two
components, a sliding door 190 and an upper door 192. When open,
the sliding door exposes two entries 194 and 196, and the upper
door 192 raises to provide increased head room. The entry 194
allows passengers access to a front curved row of six seats 198,
seen best in the plan view of the MOV in FIG. 17 or in FIG. 18 The
entry 196 allows passengers access to a second curved row of five
seats 200, and a rear L-shaped bench 202 (FIG. 17). The rear bench
202 of the embodiment in FIG. 17 can seat 4-6 adults
comfortably.
[0162] An important aspect of the MOV 13 shown in FIGS. 16, 17 and
18 is a low floor, which facilitates "elevator-like" platform
loading (no stepping down or stepping up is required). Platform
loading is a big advantage to the handicapped, and makes
loading/unloading easier for everyone.
[0163] As described above, it is thus seen that the present
embodiment provides an efficient, viable, safe, roadway-powered all
electric vehicle that uses, with only minor modification, the
existing network of highways, roadways, and/or garaging/parking
facilitates that are already in place to service ICE vehicles.
[0164] Further, it is seen that the RPEV system disclosed provides
a zero-emission electric vehicle system wherein the RPEV's of the
system may be recharged while such RPEV's are in operation within
the system. Hence, the RPEV's need not be taken out of service from
the system in order to be recharged, as is common with prior art
battery-storage type EV's.
[0165] Moreover, as seen from the above description, numerous
additional features may be used to enhance the RPEV system, such as
the inclusion of: (1) an onboard power meter; (2) a wide bandwidth
communications channel to allow information signals to be sent to,
and received from, the RPEV while it is in use; (3) automated
garaging that couples power to the RPEV for both replenishing the
onboard energy source and to bring the interior climate of the
vehicle to a comfortable level before the driver and/or passengers
get in; (4) electronic coupling between "master" and "salve" RPEV's
in order to increase passenger capacity; (5) inductive heating
coils at a passenger loading/unloading zone in order to increase
passenger safety; and (6) an ergonomically designed passenger
compartment in which passengers may travel safely and
comfortably.
[0166] While the invention herein disclosed has been described by
means of specific embodiments and applications thereof, numerous
modifications and variations could be made thereto by those skilled
in the art without departing from the scope of the invention set
forth in the claims.
* * * * *