U.S. patent application number 16/353514 was filed with the patent office on 2019-07-11 for system and method for all electrical operation of a mining haul truck.
The applicant listed for this patent is Siemens Industry, Inc.. Invention is credited to Joy Mazumdar.
Application Number | 20190210478 16/353514 |
Document ID | / |
Family ID | 51691150 |
Filed Date | 2019-07-11 |
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United States Patent
Application |
20190210478 |
Kind Code |
A1 |
Mazumdar; Joy |
July 11, 2019 |
System and Method for All Electrical Operation of a Mining Haul
Truck
Abstract
A mining haul truck driven by electrical wheel motors is
operated with all electrical power sources; that is, without a
diesel engine. While travelling on the loading site, the mining
haul truck is powered by an on-board energy storage system, which
may include a bank of ultracapacitors. The mining haul truck then
moves to the bottom of a trolley ramp and is coupled to trolley
lines. While travelling uphill, the mining haul truck is powered by
the trolley lines, and the on-board energy storage system is
charged by the trolley lines. When the mining haul truck reaches
the top of the trolley ramp, the mining haul truck is uncoupled
from the trolley lines. While travelling on the unloading site, the
mining haul truck is powered by the on-board energy storage system.
The on-board energy storage system may also be charged by retard
energy generated by the wheel motors during braking.
Inventors: |
Mazumdar; Joy; (Norcross,
GA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Siemens Industry, Inc. |
Alpharetta |
GA |
US |
|
|
Family ID: |
51691150 |
Appl. No.: |
16/353514 |
Filed: |
March 14, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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14038995 |
Sep 27, 2013 |
10286787 |
|
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16353514 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B60L 50/53 20190201;
Y02T 10/70 20130101; Y02T 10/646 20130101; B60L 9/00 20130101; H02P
3/14 20130101; Y02T 10/7005 20130101; B60L 2200/40 20130101; B60L
5/00 20130101; B60L 50/40 20190201; Y02T 10/64 20130101 |
International
Class: |
B60L 53/14 20190101
B60L053/14; H02P 3/14 20060101 H02P003/14; B60L 5/00 20060101
B60L005/00; B60L 50/53 20190101 B60L050/53; B60L 50/40 20190101
B60L050/40; B60L 9/00 20190101 B60L009/00 |
Claims
1. A method for supplying electrical power to an electrical motor
on an all electrically powered mining haul truck, the method
comprising the steps of: charging an on-board energy storage system
with electrical power from a trolley power system while the mining
haul truck is coupled to trolley lines of the trolley power system;
uncoupling the mining haul truck from the trolley lines; and
supplying electrical power to the electrical motor from the
on-board energy storage system while the mining haul truck is
uncoupled from the trolley lines, wherein the mining haul truck is
propelled by electrical power supplied by the trolley power system
alone, or by the on-board energy storage system alone, or a
combination of the trolley power system and the on-board energy
storage system, without mechanical power supplied by a mechanical
engine to propel the mining haul truck.
2. The method of claim 1, wherein: the on-board energy storage
system comprises at least one ultracapacitor.
3. The method of claim 1, wherein: the on-board energy storage
system comprises at least one battery.
4. The method of claim 1, further comprising: supplying electrical
power to the electrical motor from the trolley power system while
the mining haul truck is travelling on an uphill grade; and
charging the on-board energy storage system with electrical power
from the trolley power system while the mining haul truck is
travelling on the uphill grade.
5. The method of claim 1, further comprising: supplying electrical
power to the electrical motor from the trolley power system while
the mining haul truck is travelling on a downhill grade; and
charging the on-board energy storage system with electrical power
from the trolley power system while the mining haul truck is
travelling on the downhill grade.
6. The method of claim 1, further comprising: charging the on-board
energy storage system with electrical power generated by the
electrical motor during braking of the mining haul truck.
7. The method of claim 4, further comprising: charging the on-board
energy storage system with electrical power generated by the
electrical motor during braking of the mining haul truck.
8. The method of claim 5, further comprising: charging the on-board
energy storage system with electrical power generated by the
electrical motor during braking of the mining haul truck.
9. An electrical power system for supplying electrical power to an
electrical motor on an all electrically powered mining haul truck,
the electrical power system comprising: an on-board energy storage
system; an inverter configured to: receive electrical power from
the on-board electrical energy storage system; receive electrical
power from a trolley power system; and supply electrical power to
the electrical motor; and a controller configured to: charge the
on-board energy storage system with electrical power from the
trolley power system while the mining haul truck is coupled to
trolley lines of the trolley power system; and supply electrical
power to the electrical motor from the on-board energy storage
system, wherein the mining haul truck is configured to be propelled
by electrical power supplied by at least one of the trolley power
system alone, the on-board energy storage system alone, or a
combination thereof without mechanical power supplied by a
mechanical engine to propel the mining haul truck.
10. The electrical power system of claim 9, wherein: the on-board
energy storage system comprises at least one ultracapacitor.
11. The electrical power system of claim 9, wherein: the on-board
energy storage system comprises at least one battery.
12. The electrical power system of claim 9, wherein: the on-board
energy storage system is configured to be charged with electrical
power generated by the electrical motor during braking of the
mining haul truck.
13. The electrical power system of claim 9, wherein the controller
is further configured to: supply electrical power to the electrical
motor from the trolley power system while the on-board energy
storage system is being charged by the trolley power system.
14. A method for operating an all electrically powered mining haul
truck comprising an electrical motor, the method comprising:
charging an on-board energy storage system with electrical power
from a trolley power system while the mining haul truck is coupled
to trolley lines of the trolley power system; uncoupling the mining
haul truck from the trolley lines; supplying electrical power to
the electrical motor from the on-board energy storage system;
driving the mining haul truck to a loading site; and filling the
mining haul truck with a payload, wherein the mining haul truck is
propelled by electrical power supplied by the trolley power system
alone, or by the on-board energy storage system alone, or a
combination of the trolley power system and the on-board energy
storage system, without mechanical power supplied by a mechanical
engine to propel the mining haul truck.
15. The method of claim 14, further comprising: charging the
on-board energy storage system with electrical power generated by
the electrical motor during braking of the mining haul truck.
16. The method of claim 14, further comprising: driving the mining
haul truck to a trolley ramp; coupling the mining haul truck to the
trolley lines; supplying electrical power to the electrical motor
from the trolley lines; driving the mining haul truck along the
trolley ramp; and charging the on-board energy storage system with
electrical power supplied from the trolley lines.
17. The method of claim 16, further comprising: charging the
on-board energy storage system with electrical power generated by
the electrical motor during braking of the mining haul truck.
18. The method of claim 16, further comprising: driving the mining
haul truck to an unloading site; and unloading the payload from the
mining haul truck.
19. The method of claim 18, further comprising: charging the
on-board energy storage system with electrical power generated by
the electrical motor during braking of the mining haul truck.
20. The method of claim 14, wherein: the on-board energy storage
system comprises at least one ultracapacitor or at least one
battery.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation of U.S. patent
application Ser. No. 14/038,995 filed 27 Sep. 2013 in the US Patent
and Trademark Office, the content of which is hereby incorporated
herein in its entirety.
BACKGROUND OF THE INVENTION
[0002] The present invention relates generally to power systems for
mining haul trucks, and more particularly to a system and method
for all electrical operation of a mining haul truck.
[0003] Mining haul trucks are typically equipped with electrical
drive motors. Under demanding conditions, such as travel on an
uphill grade, electrical power can be supplied by a trolley line.
The mining haul truck draws electrical power from the trolley line
via a pantograph. Under some travel conditions, such as inside a
mining pit, around a crusher, and on level surfaces, however, the
mining haul truck operates independently of a trolley line.
Electrical power is then supplied by an electrical generator
powered by a diesel engine. Diesel engines require delivery and
storage of a supply of fuel and require regular maintenance. The
exhaust gases from diesel engines, furthermore, contribute to air
pollution.
BRIEF SUMMARY OF THE INVENTION
[0004] In an embodiment of the invention, a mining haul truck
driven by electrical motors is operated from all electrical power
sources, without the need for a diesel engine driving a generator.
When the mining haul truck is travelling on substantially flat
ground, electrical power is supplied by an on-board energy storage
system. When the mining haul truck is travelling along an uphill
grade, electrical power is supplied by trolley lines. The on-board
energy storage system is also charged with electrical power from
the trolley lines. In an embodiment of the invention, the on-board
energy storage system is charged with retard energy captured from
the electrical motors during braking.
[0005] These and other advantages of the invention will be apparent
to those of ordinary skill in the art by reference to the following
detailed description and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 shows a single-line diagram of a prior-art
diesel-powered electrical system for a mining haul truck;
[0007] FIG. 2 shows a single-line diagram of a prior-art trolley
power system for a mining haul truck;
[0008] FIG. 3 shows a schematic of a first travel scenario for a
mining haul truck;
[0009] FIG. 4 shows a schematic of a second travel scenario for a
mining haul truck;
[0010] FIG. 5A and FIG. 5B show a flowchart of a process for all
electrical operation of a mining haul truck;
[0011] FIG. 6 shows a schematic of a power system with an
ultracapacitor energy storage system;
[0012] FIG. 7 shows a plot of vehicle speed as a function of travel
time and a plot of vehicle acceleration as a function of travel
time;
[0013] FIG. 8 shows a plot of vehicle tractive effort as a function
of travel time and a plot of vehicle drive drag as a function of
travel time;
[0014] FIG. 9 shows a plot of travel distance as a function of
travel time; and
[0015] FIG. 10 shows a schematic of an ultracapacitor energy
management controller.
DETAILED DESCRIPTION
[0016] FIG. 1 shows a single-line diagram of a prior-art mining
haul truck power system. The mining haul truck has two drive
wheels. Each wheel is driven by a 3-phase alternating-current (AC)
wheel motor (M). The wheel motors are referenced as the wheel motor
110 and the wheel motor 114. Electrical power is supplied by a
diesel engine 102 driving a 3-phase AC generator (G) 104. (Other
types of mechanical engines may be used; diesel engines are typical
in mining operations.) The coupling 124 couples the diesel engine
102 to the generator 104. The diesel engine 102 and the generator
104 are mounted on the mining haul truck. The AC output of the
generator 104 is fed into the rectifiers 106. The direct current
(DC) output of the rectifiers 106 is fed into a set of inverters.
The inverters 108 supply 3-phase AC power to the wheel motor 110.
Similarly, the inverters 112 supply 3-phase AC power to the wheel
motor 114. The chopper 116 and the power resistor grid 118
dissipate energy from the wheel motor 110 during braking action.
Similarly, the chopper 120 and the power resistor grid 122
dissipate energy from the wheel motor 114 during braking action.
Braking action is described in more detail below.
[0017] In the power system shown in FIG. 1, the entire power
requirements for the wheel motor 110 and the wheel motor 114 are
supplied by the diesel engine 102. Performance (as determined, for
example, by acceleration and speed) of the mining haul truck is
limited by the power capacity of the diesel engine. In particular,
when the mining haul truck, filled with a heavy payload, is
travelling along an uphill grade, the diesel engine may be stressed
to maximum capacity. One method for reducing the power demand on
the diesel engine as the mining haul truck travels on an uphill
grade is to power the wheel motors entirely via electrical power
drawn from a trolley line. During this operational mode, the
generator 104 is disconnected from the diesel engine 102 via the
coupling 124. The diesel engine then idles on uphill grades. As a
result, fuel consumption is reduced by .about.95%; noise and
exhaust emissions are reduced; and productivity and engine life are
increased.
[0018] FIG. 2 shows a single-line diagram of a prior-art mining
haul truck power system including an overhead trolley power system.
Similar to the power system shown in FIG. 1, the diesel engine 202
is connected via the coupling 204 to the 3-phase AC generator 206.
The AC output of the generator 206 is fed into the rectifiers 208.
The DC output of the rectifiers 208 is fed into the inverters 210,
which provide power to the wheel motor 212, and into the inverters
218, which provide power to the wheel motor 220.
[0019] The inputs of the inverters 210 and the inverters 218 can
also be connected to DC power supplied by the electric substation
250 via the trolley line 230 and the trolley line 232. A trolley
line is also referred to as an overhead line. Electrical connection
of the mining haul truck to the trolley line 230 and the trolley
line 232 is implemented via the pantograph arm 234 and the
pantograph arm 236, respectively. The throw switch 240
connects/disconnects the inputs of the inverters 210 and the
inverters 218 to the trolley line 230 and the trolley line 232.
There is also an auxiliary breaker 238. As mentioned above, when
the mining haul truck is powered by the trolley power system, the
diesel engine 202 is typically disconnected from the generator 206
via the coupling 204.
[0020] FIG. 3 shows a mining site in which the loading site is
downhill from the unloading site; for example, the loading site is
at the bottom of a pit, and the payload is trucked out of the pit.
The loading site 309 is located within the region 321. Within the
region 321, the mining haul truck 302 is not powered by trolley
lines. The unloading site 339 is located within the region 351.
Within the region 351, the mining haul truck 302 is not powered by
trolley lines. Typically, the terrain within the region 321 and
within the region 351 is substantially flat.
[0021] In the uphill direction, the region 321 and the region 351
are connected by the trolley ramp 371, along which electrical power
is available from the trolley lines 370 (for simplicity, the
trolley lines 370 refer to a pair of trolley lines). In the
downhill direction, the region 351 and the region 321 are connected
by the trolley ramp 361, along which electrical power is available
from the trolley lines 360. The trolley lines 370 and the trolley
lines 360 are supported overhead by the support arms 312 mounted on
the support poles 310.
[0022] In an embodiment of the invention, the mining haul truck is
equipped with an on-board energy storage system (OBESS) that
provides electrical power when the mining haul truck is operating
within region 321 or within region 351. A diesel engine and
generator are not needed. An OBESS refers to an energy storage
system that travels with the mining haul truck (for example,
mounted on the mining haul truck or attached to the mining haul
truck or mounted on a trailer attached to the mining haul truck).
In an embodiment of the invention, an OBESS includes a bank of
ultracapacitors, a bank of batteries, or a bank of ultracapacitors
and a bank of batteries. Further details of an OBESS are provided
below. All electrical operation of the mining haul truck is first
described.
[0023] Refer to travel scenario shown in FIG. 3. Powered by the
OBESS, the mining haul truck 302 starts in region 321 at position P
301 and moves to the loading site 309. At the loading site 309, an
electric shovel (not shown) fills the payload 304 (such as ore)
onto the mining haul truck 302, which then leaves the loading site
309 at position P 303. The mining haul truck 302 then moves to
position P 305, the entrance to the trolley ramp 371. The mining
haul truck 302 is coupled to the trolley lines 370. Under trolley
power (trolley power refers to electrical power drawn from the
trolley lines), the mining haul truck 302 moves up the trolley ramp
371 (shown as position P 373) and arrives at position P 331. While
the mining haul truck 302 is coupled to the trolley lines 370,
trolley power is used to recharge the OBESS.
[0024] Position P 331 is the exit for the trolley ramp 371. The
mining haul truck 302 is then uncoupled from the trolley lines 370.
Powered by the OBESS, the mining haul truck 302 travels to position
P 333 and then to the unloading site 339, where the mining haul
truck 302 unloads the payload 304. The mining haul truck then
departs the unloading site 339 at position P 335 and moves to
position P 337, the entrance to the trolley ramp 361. The mining
haul truck 302 is coupled to the trolley lines 360. Under trolley
power, the mining haul truck 302 moves down the trolley ramp 361
(shown as position P 363) and arrives at position P 307. While the
mining haul truck 302 is coupled to the trolley lines 360, trolley
power is used to recharge the OBESS.
[0025] Position 307 is the exit for the trolley ramp 361. The
mining haul truck 302 is then uncoupled from the trolley lines 360.
Powered by the OBESS, the mining haul truck 302 moves to the
position P 301 to start another work cycle.
[0026] Refer to travel scenario shown in FIG. 4, which shows a
mining site in which the loading site is uphill from the unloading
site. The loading site 409 is located within the region 421. Within
the region 421, the mining haul truck 302 is not powered by trolley
lines. The unloading site 439 is located within the region 451.
Within the region 451, the mining haul truck 302 is not powered by
trolley lines. Typically, the terrain within the region 421 and
within the region 451 is substantially flat.
[0027] In the uphill direction, the region 451 and the region 421
are connected by the trolley ramp 471, along which trolley power is
available from the trolley lines 470. In the downhill direction,
the region 421 and the region 451 are connected by the trolley ramp
461, along which trolley power is available from the trolley lines
460. The trolley lines 470 and the trolley lines 460 are supported
overhead by the support arms 412 mounted on the support poles
410.
[0028] Powered by an OBESS, the mining haul truck 302 starts in
region 421 at position P 401 and moves to the loading site 409. At
the loading site 409, an electric shovel (not shown) fills the
payload 404 (such as ore) onto the mining haul truck 302, which
then leaves the loading site 409 at position P 403. The mining haul
truck 302 then moves to position P 405, the entrance to the trolley
ramp 461. The mining haul truck 302 is coupled to the trolley lines
460. Under trolley power, the mining haul truck 302 moves down the
trolley ramp 461 (shown as position P 463) and arrives at position
P 431. While the mining haul truck 302 is coupled to the trolley
lines 460, trolley power is used to recharge the OBESS.
[0029] Position P 431 is the exit for the trolley ramp 461. The
mining haul truck 302 is then uncoupled from the trolley lines 460.
Powered by the OBESS, the mining haul truck 302 travels to position
P 433 and then to the unloading site 439, where the mining haul
truck 302 unloads the payload 404. The mining haul truck 302 then
departs the unloading site 439 at position P 435 and moves to
position P 437, the entrance to the trolley ramp 471. The mining
haul truck 302 is coupled to the trolley lines 470. Under trolley
power, the mining haul truck 302 moves up the trolley ramp 471
(shown as position P 473) and arrives at position P 407. While the
mining haul truck 302 is coupled to the trolley lines 470, trolley
power is used to recharge the OBESS.
[0030] Position P 407 is the exit for the trolley ramp 471. The
mining haul truck 302 is then uncoupled from the trolley lines 470.
Powered by the OBESS, the mining haul truck 302 moves to the
position P 401 to start another work cycle.
[0031] A method for all electrical operation of a mining haul truck
is summarized in the flowchart of FIG. 5A and FIG. 5B. In step 502,
the mining haul truck starts in region 1. In step 504, the on-board
energy storage system (OBESS) is initially charged from an
available electrical power source (such as a charging station,
trolley lines, or diesel engine and generator). In step 506,
powered by the OBESS, the mining haul truck travels within the
region 1 (for example, travels to a loading site and receives a
payload). In step 508, powered by the OBESS, the mining haul truck
travels to the trolley ramp 1.
[0032] In step 510, the mining haul truck is coupled to the trolley
lines 1. In step 512, powered by the trolley lines 1, the mining
haul truck departs region 1. In step 514, powered by the trolley
lines 1, the mining haul truck travels along the trolley ramp 1.
The OBESS is charged by electrical power from the trolley lines 1.
In step 516, powered by the trolley lines 1, the mining haul truck
arrives at region 2.
[0033] In step 518, the mining haul truck is uncoupled from the
trolley lines 1. In step 520, powered by the OBESS, the mining haul
truck travels within the region 2 (for example, travels to an
unloading site and dumps the payload). In step 522, powered by the
OBESS, the mining haul truck travels to the trolley ramp 2.
[0034] In step 524, the mining haul truck is coupled to the trolley
lines 2. In step 526, powered by the trolley lines 2, the mining
haul truck departs region 2. In step 528, powered by the trolley
lines 2, the mining haul truck travels along the trolley ramp 2.
The OBESS is charged by electrical power from the trolley lines 2.
In step 530, powered by the trolley lines 2, the mining haul truck
arrives at region 1. In step 532, the mining haul truck is
uncoupled from the trolley lines 2. The mining haul truck has a
charged OBESS and is ready to start another work cycle.
[0035] In an embodiment of the invention, the OBESS is charged with
retard energy from the wheel motors. To slow down a moving mining
haul truck, the mining haul truck drive system operates in a retard
mode. Under normal operation, an electrical motor converts
electrical energy into mechanical energy. The operating mode in
which an electrical motor converts electrical energy into
mechanical energy is referred to as the propel mode, and a time
interval during which the electrical motor operates in a propel
mode is referred to as a propel interval. An electrical motor can
also be operated in reverse as a generator to convert mechanical
energy into electrical energy (referred to as retard energy), which
is fed into inverters. The operating mode in which the electrical
motor converts mechanical energy into electrical energy is referred
to as the retard mode, and a time interval during which the
electrical motor operates in a retard mode is referred to as a
retard interval.
[0036] Typically, braking choppers, connected to the inverters,
channel the power into a power resistor grid that continuously
dissipates the retard energy until the mining haul truck reaches
standstill; that is, the retard energy is dissipated as waste heat.
Braking is smooth, similar to the braking operation in a car, but
without mechanical brake wear. Refer to the prior-art power system
shown in FIG. 2, for example. The chopper 214 and the power
resistor grid 216 provide the braking action for the wheel motor
212. Similarly, the chopper 222 and the power resistor grid 224
provide the braking action for the wheel motor 220.
[0037] In an embodiment of the invention, however, an OBESS is
integrated into the mining haul truck power system to recover and
store the retard energy. In particular, when a mining haul truck is
travelling downhill, substantial quantities of retard energy can be
captured and stored (especially if the mining haul truck is
carrying a heavy payload), since the mining haul truck is
frequently braking, and therefore there are frequent intervals
during which the wheel motors are operating in the retard mode.
Depending on the terrain, retard energy can also be captured during
the uphill trip; retard energy can also be captured while the
mining haul truck is travelling on level ground.
[0038] The retard energy is then used to charge the OBESS. In an
embodiment of the invention, the OBESS is implemented with an
ultracapacitor system comprising an ultracapacitor bank. The amount
of energy that can be stored in the ultracapacitor system depends
on the size of the ultracapacitor bank. The OBESS can also be
implemented with a rechargeable battery system comprising a battery
bank. The amount of energy that can be stored in the battery system
depends on the size of the battery bank. The OBESS can also be
implemented with combinations of ultracapacitor banks and battery
banks. Storage capacity requirements are described below.
[0039] An ultracapacitor can provide high power densities. For
increased electrical energy storage, multiple ultracapacitors can
be connected in series and parallel to form an ultracapacitor bank.
Electrical current flowing into an ultracapacitor charges the
ultracapacitor, and electrical energy is stored via charge
separation at an electrode-electrolyte interface. The stored
electrical energy can then later be used to output an electrical
current. To maximize the lifetime of an ultracapacitor, the
ultracapacitor is not fully discharged. Typically, the
ultracapacitor is discharged until its voltage drops to a minimum
user-defined lower voltage limit. The lower voltage limit, for
example, can be one-half of the initial fully-charged voltage.
[0040] FIG. 6 shows a schematic of an OBESS 626 integrated into a
trolley power system. The wheel motors 610 are powered by the motor
drive system 630, which includes the DC link capacitor 606 and the
inverters 608. The trolley DC power system 604 provides DC power to
the motor drive system 630 via trolley lines. In the example shown,
the OBESS 626 includes the ultracapacitor electrical energy storage
unit 614 and the ultracapacitor energy management controller 612.
The ultracapacitor electrical energy storage unit 614 comprises the
DC-to-DC converter 618, the choke/reactor 622, and the
ultracapacitor bank 624. The ultracapacitor electrical energy
storage unit 614 can be disconnected from the motor drive system
630 via the connect/disconnect switch 616.
[0041] The ultracapacitor electrical energy storage unit 614 is
managed by the ultracapacitor energy management controller 612. The
ultracapacitor energy management controller 612 can also receive
motor drive system data 628, which characterizes operation of the
motor drive system 630. The motor drive system data 628 includes,
for example, DC link voltage, current, and temperature. In response
to control signals or control commands from the ultracapacitor
energy management controller 612, the ultracapacitor electrical
energy storage unit 614 can (a) transmit electrical energy to the
wheel motors, (b) receive electrical energy from the trolley DC
power system, or (c) receive retard electrical energy from the
wheel motors. If the ultracapacitor bank becomes fully charged,
excess retard energy can be dissipated in the grid resistors.
Excess retard energy can also be transmitted via the trolley lines
and stored in an auxiliary energy storage system or transmitted via
the trolley lines and returned to the utility grid via a
bidirectional electric substation (as described in US Patent
Application Publication No. 2011/0094841).
[0042] An embodiment of a computational system for implementing the
ultracapacitor energy management controller 612 (FIG. 6) is shown
in FIG. 10. The computational system 1002 is typically located in
the mining haul truck; however, other locations are possible. One
skilled in the art can construct the computational system 1002 from
various combinations of hardware, firmware, and software. One
skilled in the art can construct the computational system 1002 from
various electronic components, including one or more general
purpose processors (such as microprocessors), one or more digital
signal processors, one or more application-specific integrated
circuits (ASICs), and one or more field-programmable gate arrays
(FPGAs).
[0043] The computational system 1002 comprises the computer 1006,
which includes a processor [referred to as the central processing
unit (CPU) 1008], memory 1010, and a data storage device 1012. The
data storage device 1012 comprises at least one persistent,
tangible computer readable medium, such as non-volatile
semiconductor memory, a magnetic hard drive, and a compact disc
read only memory. In an embodiment of the invention, the computer
1006 is implemented as an integrated device.
[0044] The computational system 1002 can further comprise a user
input/output interface 1014, which interfaces the computer 1006 to
a user input/output device 1022. Examples of the input/output
device 1022 include a keyboard, a mouse, and a local access
terminal. Data, including computer executable code, can be
transferred to and from the computer 1006 via the input/output
interface 1014.
[0045] The computational system 1002 can further comprise a
communications network interface 1016, which interfaces the
computer 1006 with a remote access network 1024. Examples of the
remote access network 1024 include a local area network and a wide
area network (communications links can be wireless). A user can
access the computer 1006 via a remote access terminal (not shown).
Data, including computer executable code, can be transferred to and
from the computer 1006 via the communications network interface
1016.
[0046] The computational system 1002 can further comprise the
ultracapacitor electrical energy storage unit interface 1018, which
interfaces the computer 1006 with the ultracapacitor electrical
energy storage unit 614 (see FIG. 6). The computational system 1002
can further comprise a motor drive system interface 1020, which
interfaces the computer 1006 with the motor drive system 630 (see
FIG. 6). The motor drive system interface 1020, for example,
receives the motor drive system data 628.
[0047] As is well known, a computer operates under control of
computer software, which defines the overall operation of the
computer and applications. The CPU 1008 controls the overall
operation of the computer and applications by executing computer
program instructions that define the overall operation and
applications. The computer program instructions can be stored in
the data storage device 1012 and loaded into memory 1010 when
execution of the program instructions is desired.
[0048] The method steps shown in the flowchart in FIG. 5A and FIG.
5B can be defined by computer program instructions stored in the
memory 1010 or in the data storage device 1012 (or in a combination
of memory 1010 and the data storage device 1012) and controlled by
the CPU 1008 executing the computer program instructions. For
example, the computer program instructions can be implemented as
computer executable code programmed by one skilled in the art to
perform algorithms implementing the method steps shown in the
flowchart in FIG. 5A and FIG. 5B. Accordingly, by executing the
computer program instructions, the CPU 1008 executes algorithms
implementing the method steps shown in the flowchart in FIG. 5A and
FIG. 5B.
[0049] Required storage capacity of the OBESS can be estimated from
calculations. For example, assume the following haul profile
(travel scenario similar to that shown in FIG. 3): [0050] 500 m,
flat: shovel (loading site) to trolley ramp, loaded [0051] 2000 m,
10% grade: trolley ramp, loaded [0052] 500 m, flat: trolley ramp to
dump (unloading site), loaded [0053] 500 m, flat: dump to trolley
ramp, empty [0054] 2000 m, -10% grade: trolley ramp, empty [0055]
500 m, flat: trolley ramp to shovel, empty. Each leg of the profile
specifies (a) the distance traveled, (b) slope of ground, (c)
travel path, and (d) payload status of the mining haul truck. The
weight of the empty mining haul truck is assumed to be 160,000 kg;
and the weight of the loaded mining haul truck is assumed to be
400,000 kg.
[0056] The speed and acceleration for the mining haul truck running
on the above profile is shown in FIG. 7. Plot 702 shows the vehicle
speed (km/hr) as a function of travel time (s). Plot 704 shows the
vehicle acceleration (m/s.sup.2) as a function of travel time (s).
Refer to FIG. 8. Plot 802 shows the vehicle tractive effort (kN) as
a function of travel time (s). Plot 804 shows the vehicle drive
drag (kN) as a function of travel time (s). Refer to FIG. 9. Plot
902 shows the travel distance (m) as a function of travel time
(s).
[0057] From FIG. 7, it can be seen that the mining haul truck needs
about 50 s to reach the trolley ramp. Similarly, it would require
about the same time to travel from the trolley ramp to the dump
(unloading site). Returning from the dump to the trolley ramp would
require less time since the mining haul truck is empty. The mining
haul truck needs approximately 24 kWh of energy from the OBESS to
move the mining haul truck from the shovel (loading site) to the
trolley ramp. For all other areas, the energy required from the
OBESS would be equal to or less than 24 kWh.
[0058] Selection of the appropriate energy storage device is
important. Mines are often located in remote locations with extreme
climatic conditions. Extreme cold conditions with temperatures
below -20.degree. C. pose particular challenges. In addition,
mining haul trucks are subjected to extreme shocks and vibrations.
Appropriate candidates for energy storage are traction grade
ultracapacitors and traction grade batteries.
[0059] Refer back to the travel scenarios shown in FIG. 3 and in
FIG. 4. Trolley power is supplied on both the uphill path and the
downhill path. In some scenarios, trolley power is not needed on
the downhill path if the OBESS is sufficiently charged at the start
of the downhill path, and if sufficient retard energy is generated
along the downhill path to maintain sufficient charge in the OBESS
for the mining haul truck to operate, while powered by the OBESS,
along the entirety of the downhill path and within the downhill
region (region 321 in FIG. 3 or region 451 in FIG. 4).
[0060] Embodiments of the invention can be retrofitted into an
existing mining haul truck that has a diesel engine and a
generator. The diesel engine can be retained for operation under
fault conditions or used to charge the OBESS while idling. In other
embodiments of the invention, a mining haul truck is not equipped
with a diesel engine and generator: the mining haul truck is
propelled by electrical power supplied by trolley lines alone, an
OBESS alone, or a combination of trolley lines and an OBESS.
[0061] Embodiments of the invention have been described with
reference to a mining haul truck. One skilled in the art can
develop embodiments of the invention for other vehicles driven by
electrical motors.
[0062] The foregoing Detailed Description is to be understood as
being in every respect illustrative and exemplary, but not
restrictive, and the scope of the invention disclosed herein is not
to be determined from the Detailed Description, but rather from the
claims as interpreted according to the full breadth permitted by
the patent laws. It is to be understood that the embodiments shown
and described herein are only illustrative of the principles of the
present invention and that various modifications may be implemented
by those skilled in the art without departing from the scope and
spirit of the invention. Those skilled in the art could implement
various other feature combinations without departing from the scope
and spirit of the invention.
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