U.S. patent application number 12/379125 was filed with the patent office on 2009-09-03 for propulsion system.
This patent application is currently assigned to GLACIER BAY, INC.. Invention is credited to Gerald Allen Alston, Justin Dobbs, Bruce Nelson.
Application Number | 20090222155 12/379125 |
Document ID | / |
Family ID | 40707689 |
Filed Date | 2009-09-03 |
United States Patent
Application |
20090222155 |
Kind Code |
A1 |
Alston; Gerald Allen ; et
al. |
September 3, 2009 |
Propulsion system
Abstract
A system for automatically controlling the speed of a battery
powered electric propulsion motor driving a shaft connected to a
propeller located on a sailing vessel. The system includes a user
interface for selecting either a neutral, a regeneration or a
forward thrust operating mode. The system also includes a
controller configured to receive input from a motor speed sensor
and a motor current sensor. The controller adjust the speed of the
motor to the correct motor speed. The controller is configured so
that in the neutral mode the correct motor speed is the speed
required to substantially eliminate thrust on the shaft.
Inventors: |
Alston; Gerald Allen; (Union
City, CA) ; Nelson; Bruce; (Union City, CA) ;
Dobbs; Justin; (Union City, CA) |
Correspondence
Address: |
FOLEY AND LARDNER LLP;SUITE 500
3000 K STREET NW
WASHINGTON
DC
20007
US
|
Assignee: |
GLACIER BAY, INC.
|
Family ID: |
40707689 |
Appl. No.: |
12/379125 |
Filed: |
February 12, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61064087 |
Feb 15, 2008 |
|
|
|
Current U.S.
Class: |
701/21 ; 440/1;
440/84 |
Current CPC
Class: |
B63J 2003/046 20130101;
B63H 21/20 20130101; B63H 21/213 20130101; B63H 21/00 20130101;
Y02T 70/70 20130101; B63J 3/04 20130101; Y02T 70/00 20130101 |
Class at
Publication: |
701/21 ; 440/84;
440/1 |
International
Class: |
B63H 21/21 20060101
B63H021/21 |
Claims
1. A system for controlling an electric propulsion motor for
driving a propeller of a sailing vessel, the system comprising: a
user interface for selecting either a sail mode or a normal
operation mode; a controller configured to operate in the sail mode
to control the electric propulsion motor to substantially eliminate
the drag force being applied by the propeller to the vessel.
2. A system for automatically controlling the speed of a battery
powered electric propulsion motor driving a shaft connected to a
propeller located on a sailing vessel comprising: a user interface
for selecting an operating mode of the system; a motor speed
sensor; a controller configured to receive input from the motor
speed sensor and adjusts the speed of the motor to the correct
motor speed; and wherein the controller executes an algorithm to
determine the correct motor speed based on the selected operating
mode. wherein the operating modes include neutral, regeneration and
forward thrust modes; wherein the controller is configured so that
in the neutral mode the correct motor speed is the speed required
to substantially eliminate thrust on the shaft.
3. The system of claim 2, wherein the system is configured so that
selection of the regeneration mode includes selecting a desired
amount of power generation and wherein the controller is configured
so that in the regeneration mode the correct motor speed is the
speed required to produce the desired amount of power generation
with the minimum amount of thrust on the shaft.
4. The system of claim 2, wherein the system is configured so that
when the regeneration mode is selected the controller is configured
to adjust the motor speed to produce the maximum amount of power
generation without exceeding a maximum amount of drag.
5. The system of claim 2, wherein system is configured so that when
the forward thrust mode is selected the user interface permits the
selection of a minimum transit speed of the vessel and the
controller operates to adjust the motor speed to so that the
minimum transit speed is achieved.
6. The system of claim 2, wherein the system is configured so that
when the forward thrust mode is selected the user interface permits
the selection of an additional power boost and the motor speed is
controlled based on the amount of power boost selected.
7. The system of claim 6, wherein the controller adjusts the motor
speed based on both the power boost selected and the remaining
capacity of the battery.
8. The system of claim 6, wherein user interface permits selection
of the duration of the voyage and the controller adjust the motor
speed based on both the power boost selected and the duration of
the voyage selected by the user.
9. The system of claim 2, wherein the system is configured so that
selection of the forward thrust mode includes selecting a desired
amount of forward thrust and wherein the controller is configured
so that in the forward thrust mode the correct motor speed is the
speed required to produce the desired amount of forward thrust on
the shaft.
10. The system of claim 2, wherein the controller adjusts the motor
speed by adjusting a current to the motor.
11. The system of claim 9, further comprising a pressure sensor for
measuring the forward thrust on the shaft.
12. The system of claim 9, wherein the system is configured so that
when the desired amount of thrust is selected the controller
determines a corresponding amount of current to be supplied to the
motor.
13. A system for automatically controlling the speed of a battery
powered electric propulsion motor located on a sailing vessel
comprising: a user interface for selecting an operating mode of the
system; a motor speed sensor; a controller configured to receive
input from the motor speed sensor and adjusts the speed of the
motor to the correct motor speed; and wherein the controller
executes an algorithm to determine the correct motor speed based on
the selected operating mode.
14. The system of claim 13, wherein the algorithm considers the
operating characteristics of the vessel when determining the
correct motor speed.
15. The system of claim 13, wherein the system is configured so
that the user interface does not permit the user to directly select
vessel speed or motor speed
16. The system of claim 13, wherein the algorithm includes a
learning function to determine certain operating characteristics of
the vessel.
17. The system of claim 13, further comprising a motor current
sensor and wherein the controller is configured to receive input
from the motor current sensor and wherein the controller adjusts
the motor current in order to control the motor speed.
18. A system for automatically controlling the speed of a battery
powered electric propulsion motor driving a shaft connected to a
propeller located on a sailing vessel comprising: a user interface
for selecting transit speed for the vessel; a motor speed sensor
and a motor current sensor; a controller configured to receive
input from the motor speed sensor and the motor current sensor and
adjusts the speed of the motor to the correct motor speed; and
wherein the controller executes an algorithm to determine the
operating mode necessary to achieve the selected transit speed;
wherein the operating modes include regeneration and forward thrust
modes; wherein the controller is configured to shift the motor
between the regeneration and forward thrust modes as necessary to
maintain the selected transit speed.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority to and the benefit
of U.S. Provisional Patent Application No. 61/064,087 filed Feb.
15, 2008. The foregoing provisional application is incorporated by
reference herein in its entirety.
BACKGROUND
[0002] The present application relates generally to the field of
propulsion systems for a sailing vessel. More specifically, the
present invention relates to reducing the drag caused by a
propeller for a propulsion system of a sailing vessel when the
vessel is being propelled by the wind.
[0003] Sailing vessels may include an on-board secondary power
source such as a diesel engine or a diesel/electric hybrid engine.
The secondary power source drives a propeller to provide
supplemental propulsion to the vessel. However, when the wind is
providing the propulsion for the sailing vessel and the engine is
turned off, the propeller creates drag in the water and slows the
vessel.
[0004] It would be advantageous, amongst other improved features,
to provide a system for reducing the drag created by the propeller
on a sailing vessel.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] These and other features, aspects, and advantages of the
present invention will become apparent from the following
description, appended claims, and the accompanying exemplary
embodiments shown in the drawings, which are briefly described
below.
[0006] FIG. 1 is a block diagram of an electrical system for a
sailing vessel according to one exemplary embodiment of the present
invention.
[0007] FIG. 2 is a block diagram of an electrical system for a
sailing vessel according to another exemplary embodiment of the
present invention.
[0008] FIG. 3 is a flowchart of a process for controlling an
electric propulsion motor according to one exemplary embodiment
using an algorithm with the motor in a propulsion mode or neutral
mode.
[0009] FIG. 4 is a flowchart of a process for controlling an
electric propulsion motor according to one exemplary embodiment
using an algorithm with the motor in a propulsion mode or neutral
mode.
[0010] FIG. 5 is a flowchart of a process for controlling an
electric propulsion motor according to one exemplary embodiment
using sensor to measure thrust pressure with the motor in a
propulsion mode or neutral mode.
[0011] FIG. 6 is a flowchart of a process for controlling an
electric propulsion motor according to one exemplary embodiment
using an algorithm with the motor in regeneration mode.
[0012] FIG. 7 is a flowchart of a process for controlling an
electric propulsion motor according to one exemplary embodiment
using an algorithm for maintaining the speed of the vessel over
land.
[0013] FIG. 8 is an exemplary graph of propeller efficiency and
vessel speed.
[0014] FIG. 9 is a schematic drawings of a marine vessel including
an electric propulsion system.
DETAILED DESCRIPTION
[0015] The present application relates generally to a system for
controlling the speed of a propeller on a sailing vessel. The
system is configured to run the propeller in a "sail mode" when the
boat is under sail power. In this mode, the propeller turns at a
relatively low speed to counteract the propeller load or drag
applied to the boat as it moves through the water. The "sail mode"
improves the efficiency of the boat, reducing the wind power that
is needed to counteract the drag of the propeller.
[0016] Operating in the propeller in a low drag (e.g., neutral or
sail mode) may increase the over-water speed by as much as 3/4-11/2
knots.
[0017] Referring to FIGS. 1 and 2, a block diagram of an electrical
system for a sailing vessel is shown according to exemplary
embodiments. The sailing vessel includes an on-board power source
to power a motor-driven propeller. According to an exemplary
embodiment, power is supplied by a diesel engine turning a
permanent magnet alternator or generator. The alternator powers,
for example a 240 V DC bus for the vessel. As shown in FIG. 1, the
vessel may include a rechargeable energy source such as a battery
bank to store energy from the engine. An electric motor, such as a
brushless DC permanent magnet motor is coupled to the bus with a
controller and drives a propeller. If the electrical system
includes a rechargeable energy source, the motor may receive power
from the rechargeable energy source when the engine and generator
are secured (i.e., turned off).
[0018] The power systems shown in FIGS. 1 and 2 are exemplary only.
For example, the system may or may not include various electrical
loads (e.g., appliances). Furthermore, the system need not include
additional electrical busses (e.g., the 12 V DC and 120 V AC
busses). Also, although a shore power connection via a rectifier is
shown in FIGS. 1 and 2, the present application is directed mainly
to the operation of the propulsion system when the vessel is
underway and shore power is not available.
[0019] As shown in FIG. 9, according to one exemplary embodiment,
the propulsion system for a vessel 10 may include a propulsion
motor 300. The propulsion motor drives a propeller 500 via a shaft
700. As shown in FIGS. 1 and 2, the motor may derive power from
either a generator 500 or a battery 600. The system also includes a
system controller 200 for controller the operation of the motor. As
shown in FIGS. 1 and 2, the motor will also typically include a
motor controller. The system may be controlled via inputs entered
on a user interface 100. The user interface may take the form of
any well known interfaces such as, for example, personal computer,
touch screen, joy stick, etc. Furthermore, the controller and the
user interface may be integrated such as, for example, in the case
of an on board computer system that includes a monitor/touch screen
display.
[0020] One embodiment of the propulsion system relates to a system
for controlling an electric propulsion motor for driving a
propeller of a sailing vessel. The system includes a user interface
for selecting either a sail mode or a normal operation mode, and a
controller configured to operate in the sail mode to control the
electric propulsion motor to substantially eliminate the drag force
being applied by the propeller to the vessel.
[0021] As mentioned above, the sail mode is typically selected via
the user interface 100 when the vessel is underway and the primary
propulsion power is imparted on the vessel via the vessels sail(s).
In the sail mode, the controller 200 adjusts the speed of the motor
in order to substantially eliminate the drag force being applied to
the propeller 500. The drag force may be determined indirectly by
sensing the pressure on the shaft 700 of the vessel 10. When the
motor 300 is employed to propel the vessel 10 through the water a
thrust force is placed on the vessel by the propeller via the
shaft. Typically, when the vessel 10 is driven by sail power the
propeller spins and imparts a drag on the vessel causing a force on
the shaft in the opposite direction from the forward thrust force.
In the sail mode, the controller 200 may adjust the speed of the
motor 300 so that the net force on the shaft is substantially zero.
The system includes a motor current sensor 301 and a motor speed
sensor 302 that, as shown in FIG. 9, provide input to the system
controller 200.
[0022] The force on the shaft may be determined via a thrust sensor
400. The thrust sensor 400 may sense the pressure on the shaft at a
thrust bearing, for example. The thrust sensor 400 may include any
of many well known sensor types such as, for example, the sensors
disclosed in U.S. Pat, Nos. 5,527,194; 6,289,749; 6,418,794;
6,951,145; and 7,469,593; for example. The thrust sensor 400 may
include other embodiments operating based on the characteristics
disclosed in the foregoing patents, which are incorporated by
reference herein. The foregoing patents are exemplary only, the
thrust sensor may also employ any well known sensing technique such
as, for example, pressure, piezo-electric, magnetic, etc.
[0023] As shown in FIG. 3, the controller may control the system to
reduce the applied force on the vessel, i.e. forward or drag
thrust. Although FIG. 3, does not show a step for considering a
minimum applied force, the system may include a predetermined
minimum applied force value so that the controller does not cycle
the motor controller and motor speed excessively. For example, if
the motor speed is adjusted so that the thrust on the vessel drops
below an acceptable predetermined value than the controller can
maintain the motor speed constant and no further adjustments are
necessary. The predetermined value may be substantially zero or
some greater but acceptable value based on system operation and/or,
for example, other factors such as, for example, sea state.
[0024] As described above, according to a disclosed embodiment, an
electric propulsion system for a sailing vessel is provided. The
electric propulsion system includes an electric motor driving a
propeller, a controller for controlling the operation of the motor,
and a user interface for selecting the operating mode of the
controller. The operating modes includes a sail mode and a normal
mode. The controller is configured to operate in the sail mode to
change the speed of the motor in order to substantially eliminate
or reduce below a predetermined value the drag force being applied
by the propeller to the vessel.
[0025] The system may also be controlled by reducing or eliminating
the electrical power being generated by the propulsion motor. Thus,
as shown in FIG. 6, the controller 200 may adjust the speed of the
motor in order to reduce the regenerative power created by the
propulsion motor. The controller may operate to adjust the motor
speed to maintain the regenerative power around zero (i.e., neutral
or no drag force). Although not shown in FIG. 6, the system may
include reducing the regenerative power to an acceptable
predetermined value and then maintaining the motor current
constant. The regenerative power may be measured by any well known
method such as a voltage or current sensor, for example.
[0026] As shown in FIG. 4, the system may employ motor speed and
current sensors. The speed of the motor may be controlled based on
the sensed motor current. The system controller may employ a method
wherein for a given motor speed and corresponding motor current is
known (e.g., via a lookup table, learned, or algorithm). Due to the
drag force on the vessel, there may be a mismatch between the motor
speed and the motor current. Thus, the controller seeks to
eliminate the mismatch by adjusting the current applied to the
propulsion motor. The controller may operate to adjust the motor
current to match the desired current with the actual current (i.e.,
neutral or no drag force). Although not shown in FIG. 4, the system
may include reducing the difference between the actual current and
the desired current to an acceptable predetermined value and then
maintaining the motor current constant.
[0027] As described above, the system may include a sail mode and a
normal mode. According to another embodiment, the system may also
include a regenerative mode. In particular, a system for
automatically controlling the speed of a battery powered electric
propulsion motor driving a shaft connected to a propeller located
on a sailing vessel may be provided. The system includes a user
interface for selecting an operating mode of the system, a motor
speed sensor and a motor current sensor, and a controller
configured to receive input from the motor speed sensor and the
motor current sensor and adjusts the speed of the motor to the
correct motor speed. The controller may execute an algorithm to
determine the correct motor speed based on the selected operating
mode. The operating modes may include neutral, regeneration and
forward thrust (or normal) modes. The controller is configured so
that in the neutral mode the correct motor speed is the speed
required to substantially eliminate thrust on the shaft. The
neutral mode may correspond generally to the sail mode described
above.
[0028] In the regeneration mode, the system controller may operate
to adjust the motor current to provide for the motor to generate
electrical power, such as, for example to recharge the vessel's
battery or batteries. As shown in FIG. 8, the propeller efficiency
may vary according to the speed of the vessel. Thus, the system
controller may adjust the motor current in order to place the
vessel in the optimum condition for generation of electrical power.
For example, the system controller may adjust the motor current to
counteract the force on the propeller generated by the vessel's
movement through the water in order to optimize the efficiency of
the power generation. The system includes a controller configured
to adjust the motor speed in order to maximize the power
generation.
[0029] When operating in the regenerative mode, the controller may
be configured to adjust the motor speed and current based on
different criteria. For example, the controller may adjust the
motor current in order to balance power generation with increased
drag on the vessel. Thus, the controller may adjust the motor
current to limit the power generation in order to avoid exceeding a
pre-determined amount of drag force on the vessel. In an
alternative embodiment, the controller may adjust the motor current
to maximize the power generation regardless of the impact on the
drag force on the vessel.
[0030] For example, the controller may execute an algorithm to
determine the correct motor speed based on the selected operating
mode. The user interface is configured so that selection of the
regeneration mode includes selecting a desired amount of power
generation and wherein the controller is configured so that in the
regeneration mode the correct motor speed is the speed required to
produce the desired amount of power generation with the minimum
amount of thrust on the shaft.
[0031] The embodiments disclosed herein can be employed with
conventional regenerative capable motor propulsion systems such as
disclosed in U.S. Published Patent Application 2006/0175996
(incorporated by reference herein). The motor control methodology
and operating modes disclosed herein may be used in the marine
propulsions system(s) disclosed in the foregoing patent
publication. Thus, the system controller disclosed herein may be
used to control the various propulsion systems disclosed in the
foregoing publication. The disclosed propulsion system may be
modified to accommodate the presently disclosed novel controller.
Such modifications may include the provision of a thrust sensor,
for example.
[0032] When operating in the conventional, normal or forward thrust
mode, the controller may be configured to adjust the motor speed
and current in order to supply the propulsion power requested on
the user interface. The controller may execute an algorithm to
determine the correct motor speed based on the selected operating
mode. The user interface is configured so that selection of the
forward thrust mode includes selecting a desired amount of forward
thrust and wherein the controller is configured so that in the
forward thrust mode the correct motor speed is the speed required
to produce the desired amount of forward thrust on the shaft. The
system further includes a thrust or pressure sensor for measuring
the forward thrust on the shaft. The user interface is configured
to allow the user to select a desired amount of current supplied to
the motor and wherein the desired amount of forward thrust is the
forward thrust resulting from providing the selected amount of
current to the motor.
[0033] In an alternative embodiment, a user may select a desired
speed over land instead of, for example, a desired speed in the
water. Thus, according to this embodiment, the controller receives
input from a navigation system (e.g., GPS) that provides an
indication of the vessel's position relative to land. The
controller adjusts the motor current and speed in order to maintain
the selected speed over land. The controller operation is
disclosed, for example, in FIG. 7.
[0034] Another embodiment relates to a system for automatically
controlling the speed of a battery powered auxiliary electric
propulsion motor located on a sailing vessel. The system includes a
user interface for selecting an operating mode of the system, a
motor speed sensor and a motor current sensor, and a controller
configured to receive input from the motor speed sensor and the
motor current sensor and adjusts the speed of the motor to the
correct motor speed. The controller executes an algorithm to
determine the correct motor speed based on the selected operating
mode. The algorithm considers the operating characteristics of the
vessel when determining the correct motor speed. The operating
modes may be configured to not allow the user to directly select
vessel speed or motor speed. One or more aspects of the algorithm
may be user selectable (e.g., from a lookup table), pre-programmed
(e.g., a formula), or calculated (e.g., with a learning function to
determine certain operating characteristics of the vessel). The
operating characteristics may include, for example, the relative
drag force imparted on the vessel at various vessel speeds by the
shape of the hull. Further by way of example, the operating
characteristics may be related to the efficiency of the
propeller.
[0035] The system for controlling the speed of the motor and
propeller may comprise discrete modes or may comprise a continuous
range. For example, a system may include three separate modes
(e.g., a normal operation mode where the propeller propels the
vessel, a neutral or sail mode where the propeller turns at a slow
speed to minimize the drag applied to the vessel, and a
regeneration mode where the propeller is driven by the current to
recharge the rechargeable energy source with the motor acting as a
generator). According to another exemplary embodiment, a system may
include intermediate modes between the three "main" modes. For
example, the system may include a minor propulsion mode where the
propeller turns at a speed between the normal operation mode and
the neutral mode and propels the vessel while using less power. The
system may also include a minor regeneration mode where the
propeller is allowed to be driven by the current to provide a
smaller amount of power to the rechargeable energy source. Such a
minor regeneration mode may be configured as an optimized
regeneration mode where the speed of the propeller and, thus, the
motor is adjusted so it is in the most efficient range for the
motor to act as a generator. According to still another exemplary
embodiment, the system may be configured to operate the propeller
in a continuous range between a normal operation mode, a neutral or
sail mode, and a regeneration mode.
[0036] It is important to note that the construction and
arrangement of the system for controlling the speed of the motor
and propeller as shown in the various exemplary embodiments is
illustrative only. Although only a few embodiments of the present
application have been described in detail in this disclosure, those
skilled in the art who review this disclosure will readily
appreciate that many modifications are possible (e.g., variations
in sizes, dimensions, structures, shapes and proportions of the
various elements, values of parameters, mounting arrangements, use
of materials, colors, orientations, etc.) without materially
departing from the novel teachings and advantages of the subject
matter recited in the application. For example, elements shown as
integrally formed may be constructed of multiple parts or elements,
the position of elements may be reversed or otherwise varied, and
the nature or number of discrete elements or positions may be
altered or varied. Accordingly, all such modifications are intended
to be included within the scope of the present application. The
order or sequence of any process or method steps may be varied or
re-sequenced according to alternative embodiments. Any
means-plus-function clause is intended to cover the structures
described herein as performing the recited function and not only
structural equivalents but also equivalent structures. Other
substitutions, modifications, changes and omissions may be made in
the design, operating conditions and arrangement of the exemplary
embodiments without departing from the scope of the present
application.
[0037] As noted above, embodiments within the scope of the present
application include program products comprising machine-readable
media for carrying or having machine-executable instructions or
data structures stored thereon. Such machine-readable media can be
any available media which can be accessed by a general purpose or
special purpose computer or other machine with a processor. By way
of example, such machine-readable media can comprise RAM, ROM,
EPROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk
storage or other magnetic storage devices, or any other medium
which can be used to carry or store a desired program code in the
form of machine-executable instructions or data structures and
which can be accessed by a general purpose or special purpose
computer or other machine with a processor. When information is
transferred or provided over a network or another communications
connection (either hardwired, wireless, or a combination of
hardwired or wireless) to a machine, the machine properly views the
connection as a machine-readable medium. Thus, any such connection
is properly termed a machine-readable medium. Combinations of the
above are also included within the scope of machine-readable media.
Machine-executable instructions comprise, for example, instructions
and data which cause a general purpose computer, special purpose
computer, or special purpose processing machines to perform a
certain function or group of functions.
[0038] It should be noted that although the diagrams herein may
show a specific order of method steps, it is understood that the
order of these steps may differ from what is depicted. Also two or
more steps may be performed concurrently or with partial
concurrence. Such variation will depend on the software and
hardware systems chosen and on designer choice. It is understood
that all such variations are within the scope of the application.
Likewise, software implementations of the present application could
be accomplished with standard programming techniques with
rule-based logic and other logic to accomplish the various
connection steps, processing steps, comparison steps and decision
steps.
[0039] The foregoing description of embodiments of the application
has been presented for purposes of illustration and description. It
is not intended to be exhaustive or to limit the application to the
precise form disclosed, and modifications and variations are
possible in light of the above teachings, or may be acquired from
practice of the application. The embodiments were chosen and
described in order to explain the principles of the application and
its practical application to enable one skilled in the art to
utilize the application in various embodiments and with various
modifications as are suited to the particular use contemplated.
[0040] Although the description contains many specificities, these
specificities are utilized to illustrate some of the preferred
embodiments of this application and should not be construed as
limiting the scope of the application. The scope of this
application fully encompasses other embodiments which may become
apparent to those skilled in the art. All structural, chemical, and
functional equivalents to the elements of the above-described
application that are known to those of ordinary skill in the art
are expressly incorporated herein by reference and are intended to
be encompassed by the present application. A reference to an
element in the singular is not intended to mean one and only one,
unless explicitly so stated, but rather it should be construed to
mean at least one. Furthermore, no element, component or method
step in the present disclosure is intended to be dedicated to the
public.
* * * * *