U.S. patent application number 09/735417 was filed with the patent office on 2002-06-13 for high performance brush motor driver in conjuction with low cost sr motor driver.
This patent application is currently assigned to Delphi Technologies, Inc.. Invention is credited to Disser, Robert John, Mescher, Patrick Allen.
Application Number | 20020070693 09/735417 |
Document ID | / |
Family ID | 22620347 |
Filed Date | 2002-06-13 |
United States Patent
Application |
20020070693 |
Kind Code |
A1 |
Disser, Robert John ; et
al. |
June 13, 2002 |
HIGH PERFORMANCE BRUSH MOTOR DRIVER IN CONJUCTION WITH LOW COST SR
MOTOR DRIVER
Abstract
A combined drive circuit for a split brake system of a motor
vehicle has a switched reluctance motor and a brush motor. The
switched reluctance motor has multiple phase windings. The combined
drive circuit includes a DC power source with first and second
supply buses. A SR motor driver supplies current to the switched
reluctance motor. The SR motor driver has a first capacitor coupled
to the phase windings for storing energy from the phase windings
and a second capacitor coupled to the first capacitor and a third
supply bus, thereby developing a third supply bus voltage across
the second capacitor. A brush motor driver is coupled to the first
and second capacitor. The SR motor driver is adapted to supply
current to the brush motor. The brush motor driver includes first,
second, third and fourth switching elements coupled to the brush
motor.
Inventors: |
Disser, Robert John;
(Dayton, OH) ; Mescher, Patrick Allen; (Bellbrook,
OH) |
Correspondence
Address: |
SCOTT A. MCBAIN
DELPHI TECHNOLOGIES, INC.
Mail Code: 480-414-420
P.O. Box 5052
Troy
MI
48007-5052
US
|
Assignee: |
Delphi Technologies, Inc.
|
Family ID: |
22620347 |
Appl. No.: |
09/735417 |
Filed: |
December 12, 2000 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60170558 |
Dec 14, 1999 |
|
|
|
Current U.S.
Class: |
318/34 ;
318/701 |
Current CPC
Class: |
B60T 13/662 20130101;
B60T 13/741 20130101; H02P 5/60 20130101; B60T 13/74 20130101; B60T
7/042 20130101 |
Class at
Publication: |
318/34 ;
318/701 |
International
Class: |
H02P 001/54 |
Claims
1. A combined drive circuit for a switched reluctance motor and a
brush motor, the switched reluctance motor having multiple phase
windings, comprising: a DC power source having a first terminal
defining a first supply bus and a second terminal defining a second
supply bus, each of the phase windings having a first end connected
to the first supply bus and a second end; a third supply bus; a SR
motor driver for supplying current to the switched reluctance
motor, the SR motor driver having a first capacitor coupled to the
phase windings for storing energy from the phase windings and a
second capacitor coupled to the first capacitor and the third
supply bus, thereby developing a third supply bus voltage across
the second capacitor; and, a brush motor driver being coupled to
the first and second capacitor, the SR motor driver being adapted
to supply current to the SR brush, the brush motor driver having
first, second, third and fourth switching elements coupled to the
brush motor.
2. The combined drive circuit, as set forth in claim 1, wherein the
first, second, third, and fourth switching elements are arranged in
a H-bridge configuration.
3. The combined drive circuit, as set forth in claim 1, wherein the
third supply bus voltage is positive.
4. The combined drive circuit, as set forth in claim 1, wherein the
third supply bus voltage is negative.
5. The combined drive circuit, as set forth in claim 1, including
first and second diodes coupled to the first and second
capacitors.
6. The combined drive circuit, as set forth in claim 5, wherein the
first and second diodes are adapted to direct inductive currents
stored in a respective phase windings to one of the first and
second capacitors and another of the phase windings.
7. The combined drive circuit, as set forth in claim 1, including
first and second power transistors and first and second diodes
being coupled to the first and second capacitors.
8. The combined drive circuit, as set forth in claim 7, wherein the
first and second power transistors and the first and second diodes
are adapted to direct inductive currents stored in respective phase
windings to one of the first and second capacitors and another of
the phase windings.
9. The combined drive circuit, as set forth in claim 8, includes
third and fourth power transistors, wherein the third and fourth
power transistors and the first and second diodes are adapted to
direct inductive currents stored in respective phase windings to
one of the first and second capacitors and another of the phase
windings.
10. The combined drive circuit, as set forth in claim 1, including
a first controller for supplying a pulse width modulated signal to
the brush motor driver for controlling motor voltage and motor
current to achieve desired motor performance.
11. The combined drive circuit, as set forth in claim 10, wherein
the first controller is adapted to control the brush motor
bi-directionally in first and second directions.
12. The combined drive circuit, as set forth in claim 9, wherein
the brush motor has higher load in a first direction and wherein
the brush motor is driven by the DC power supply in the first
direction.
13. A combined drive circuit for a split brake system of a motor
vehicle, having a switched reluctance motor and a brush motor, the
switched reluctance motor having multiple phase windings,
comprising: a DC power source having a first terminal defining a
first supply bus and a second terminal defining a supply bus, each
of the phase windings having a first end connected to the first
supply bus and a second end; a third supply bus; a SR motor driver
for supplying current to the switched reluctance motor, the SR
motor driver having a first capacitor coupled to the phase windings
for storing energy from the phase windings and a second capacitor
coupled to the first capacitor and the third supply bus, thereby
developing a third supply bus voltage across the second capacitor;
and, a brush motor driver being coupled to the first and second
capacitor, the SR motor driver being adapted to supply current to
the brush motor, the brush motor driver having first, second,
third, and fourth switching elements coupled to the brush
motor.
14. The combined drive circuit, as set forth in claim 13, wherein
the first, second, third, and fourth switching elements are
arranged in a H-bridge configuration.
15. The combined drive circuit, as set forth in claim 13, wherein
the third supply bus voltage is positive.
16. The combined drive circuit, as set forth in claim 13, wherein
the third supply bus voltage is negative.
17. The combined drive circuit, as set forth in claim 13, including
first and second diodes coupled to the first and second
capacitors.
18. The combined drive circuit, as set forth in claim 17, wherein
the first and second diodes are adapted to direct inductive
currents stored in a respective phase windings to one of the first
and second capacitors and another of the phase windings.
19. The combined drive circuit, as set forth in claim 13, including
first and second power transistors and first and second diodes
being coupled to the first and second capacitors.
20. The combined drive circuit, as set forth in claim 19, wherein
the first and second power transistors and the first and second
diodes and are adapted to direct inductive currents stored in a
respective phase windings to one of the first and second capacitors
and another of the phase windings.
21. The combined drive circuit, as set forth in claim 20, includes
third and fourth power transistors, wherein the third and fourth
power transistors and the first and second diodes are adapted to
direct inductive currents stored in respective phase windings to
one of the first and second capacitors and another of the phase
windings.
22. The combined drive circuit, as set forth in claim 13, including
a first controller for supplying a pulse width modulated signal to
the brush motor driver for controlling motor voltage and motor
current to achieve desired motor performance.
23. The combined drive circuit, as set forth in claim 22, wherein
the first controller is adapted to control the brush motor
bi-directionally in first and second directions.
24. The combined drive circuit, as set forth in claim 23, wherein
the brush motor has higher load in a first direction and wherein
the brush motor is driven by the DC power supply in the first
direction.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Patent Application Serial No. 60/170,558, filed Dec. 14, 1999.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to electric motors
and, more particularly, to a combined driver circuit for a brush
motor and a switched reluctance motor.
[0004] 2. Background of the Invention
[0005] Electric motors are used in a variety of applications. Two
types of electric motors are brush motors and switched reluctance
motors. Each has different operating characteristics and therefore,
advantages suitable for different applications.
[0006] For example, a split brake system for a motor vehicle
typically controls a front and diagonally opposed rear brake. The
front brake requires high response performance and the rear brake
requires significantly reduced response performance. Thus, a brush
motor is used to actuate the rear brake and a switched reluctance
motor is used to actuate the front brake.
[0007] With regard to the switched reluctance motor, the drive
circuit is comprised of power switching devices and diodes for
sequentially energizing the motor phase windings in accordance with
the position of the rotor to produce a rotating magnetic field that
interacts with the rotor poles to produce torque of a desired
direction and magnitude.
[0008] A number of drive circuit topologies have been proposed to
minimize the number of power devices in an effort to reduce the
cost of the driver circuit. One such topology is described in U.S.
Pat. No. 4,835,408 issued to Ray et al. The circuit disclosed in
Ray, commonly referred to as a split-link circuit, utilizes
capacitors to establish an intermediate voltage bus. One or more of
the phase windings are coupled to the intermediate voltage bus. In
automobile applications, the supply voltage is typically 12 volts.
Such a design reduces the number of power devices required, but
only one half of the supply voltage is available for energizing the
phase windings. As a result, the efficiency of the drive is reduced
due to increased switching and conduction losses.
[0009] U.S. Pat. No. 5,900,712 issued to Disser et al, maintains a
second bus at a voltage which is either higher or lower than the
supply voltage, thereby extending the voltage range of the
supply.
[0010] With regard to the brush motor, motor direction is
controlled by the polarity of the voltage applied to the brush
terminals. Since it is desirable to maximize power to the brake, it
is desirable to apply full supply voltage to the brush
terminals.
[0011] The present invention is aimed at one or more of the
problems above.
BRIEF SUMMARY OF THE INVENTION
[0012] In one aspect of the present invention, a combined drive
circuit for a switched reluctance motor and a brush motor is
provided. The switched reluctance motor has multiple phase
windings. The combined drive circuit includes a DC power source
with first and second supply buses. A SR motor driver supplies
current to the switched reluctance motor. The SR motor driver has a
first capacitor coupled to the first and second supply buses for
storing energy from the DC power source and a second capacitor
coupled to the first capacitor and a third supply bus, thereby
developing a third supply bus voltage across the second capacitor.
A brush motor driver is coupled to the first and second capacitor.
The SR motor driver is adapted to supply current to the brush
motor. The brush motor driver has first, second, third and fourth
switching elements coupled to the brush motor.
[0013] In another aspect of the present invention, a combined drive
circuit for a split brake system of a motor vehicle is provided.
The split brake system has a switched reluctance motor and a brush
motor. The switched reluctance motor has multiple phase windings.
The combined drive circuit includes a DC power source with first
and second supply buses. A SR motor driver supplies current to the
switched reluctance motor. The SR motor driver has a first
capacitor coupled to the first and second supply buses for storing
energy from the DC power source and a second capacitor coupled to
the first capacitor and a third supply bus, thereby developing a
third supply bus voltage across the second capacitor. A brush motor
driver is coupled to the first and second capacitor. The SR motor
driver is adapted to supply current to the brush motor. The brush
motor driver has first, second, third and fourth switching elements
coupled to the brush motor.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0014] FIG. 1 is a block diagram of a combined drive circuit for a
brush motor and a switched reluctance motor;
[0015] FIG. 2 is a schematic of the combined drive circuit of FIG.
1, according to an embodiment of the present invention;
[0016] FIG. 3 is a block diagram illustrating connections between
the combined drive circuit and the brush motor of FIG. 1; and,
[0017] FIG. 4 is a block diagram illustrating connections between
the combined drive circuit and the switched reluctance motor of
FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
[0018] With reference to FIGS. 1 and 2, the present invention
provides a combined drive circuit 102 for a switched reluctance
(SR) motor 104 and a brush motor 106. The switched reluctance motor
104 includes multiple phase windings (see below). A DC power source
116 supplies power to the combined drive circuit 102. The combined
drive circuit 102 includes a brush motor driver 108 and a switched
reluctance (SR) motor driver 110. First and second controllers 112,
114 apply control signals to the brush and SR drivers 108, 110 to
control the current supplied to the respective motor 106, 104. In
the preferred embodiment, the control signals are pulse width
modulated (PWM) signals. The generation of such PWM signals and the
control of brush motors and SR motors are well known in the art,
and thus, is not further discussed.
[0019] A DC power supply 116 supplies power to the brush motor 106
and the SR motor 104 through the respective driver 108, 110. The DC
power supply 116, which may be a battery, such as a conventional
automotive storage battery, or a source of rectified AC, is
connected to the combined driver circuit 102 at first and second
supply terminals 118A, 118B.
[0020] With reference to FIG. 2, the first supply terminal 118A
defines a first supply bus 202 and the second supply terminal 118B
defines a second supply bus 204. The combined driver circuit 102
includes a third supply bus 206, as described below.
[0021] With reference to FIGS. 3 and 4, the combined driver circuit
102 includes first and second terminals, T1, T2. The brush motor
104 is coupled to the combined driver circuit 102 at the first and
second terminals, T1, T2. The combined driver circuit 102 also
includes third, fourth, fifth, sixth, seventh and eighth terminals,
T3, T4, T5, T6, T7, T8. The first controller 112 includes ninth,
tenth, eleventh, twelfth, thirteenth, and fourteenth terminals T9,
T10, T11, T12, T13, T14. The combined driver circuit 102 is coupled
to the first controller 112 via the third through fourteenth
terminals, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, as
shown.
[0022] The combined driver circuit 102 also includes fifteenth,
sixteenth, seventeenth, eighteenth, nineteenth, and twentieth
terminals, T15, T16, T17, T18, T19, T20. The SR motor 104
preferably includes first, second, third, and fourth phase windings
402A, 402C, 402B, 402D. The first phase winding 402A is connected
at a first end of the fifteenth terminal T15 and at a second end to
the twentieth terminal T20. The second phase winding 402B is
connected at a first end to the seventeenth terminal T17 and at a
second end to the nineteenth terminal T19. The third phase winding
402C is connected at a first end to the sixteenth terminal T16 and
at a second end to the twentieth terminal T20. The fourth phase
winding 402D is connected at a first end to the eighteenth terminal
T18 and at a second end to the nineteenth terminal T19.
[0023] The combined circuit driver 102 also includes twenty-first,
twenty-second, twenty-third, twenty-fourth, twenty-fifth, and
twenty-sixth terminals, T21, T22, T23, T24, T25, T26. The second
controller 114 includes twenty-seventh, twenty-eighth,
twenty-ninth, thirtieth, thirty-first, thirty-second, thirty-third
and thirty-fourth terminals, T27, T28, T29, T30, T31, T32, T33,
T34. The combined driver circuit 102 is coupled to the second
controller 114 via the twenty-first through thirty-fourth
terminals, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31,
T32, T33, T34, and the sixteenth and eighteenth terminals T16, T18,
as shown.
[0024] Returning to FIG. 2, the SR motor driver 110 includes a
first capacitor 208 and a second capacitor 210. The second
capacitor 210 is coupled to the first capacitor 208 and the third
supply bus 206. The second capacitor 210 is also coupled to the
phase windings 402A, 402B, 402C, 402D, developing a third supply
bus (B++ or times the battery voltage of B+). The SR motor driver
110 includes first, second, third, fourth, fifth and sixth power
transistors 212, 214, 216, 218, 220, 222 and first and second
free-wheeling diodes 224, 226.
[0025] The first and second power transistors and the first and
second free-wheeling diodes 224, 226, 212, 214, direct inductive
currents stored in the respective phase windings 402A, 402B, 402C,
402D to one of the capacitors 208, 210, or to another of the phase
windings 402A, 402B, 402C, 402D being energized.
[0026] The twentieth terminal T20 is coupled to the first supply
bus 202 by a first resistor 228. The nineteenth terminal T19 is
coupled to the first supply bus 202 by a second resistor 230. The
sixteenth and twenty-third terminals T16, T23 are coupled to the
first power transistor 212 by a third capacitor 232 and a third
resistor 234, respectively. The eighteenth and twenty-fifth
terminals T18, T25 are coupled to the second power transistor 214
by a fourth capacitor 236 and a fourth resistor 238,
respectively.
[0027] The twenty-first terminal T21 is coupled to the third power
transistor 216 by a fifth resistor 240. The twenty-second terminal
T22 is coupled to the fourth power transistor 218 by a sixth
resistor 242. The twenty-fourth terminal T24 is coupled to the
fourth power transistor 220 by a seventh resistor 244. The
twenty-sixth terminal T26 is coupled to the sixth power transistor
222 by a eighth resistor 246.
[0028] The second controller 114 generates a pulse-width modulated
(PWM) signal in order to control the SR motor 104 via the SR motor
driver 110. Such a system is disclosed in U.S. Pat. No. 5,900,712
issued May 4, 1999 to Robert J. Disser, et al (Disser), which is
hereby incorporated by reference. While the SR motor driver 110
described above generates a supply voltage above the DC power
supply voltage 116, the driver 110 could be adapted to generate a
supply voltage having a negative magnitude of B-. Such a circuit is
also described in Disser. Other embodiment of the SR motor driver
110 are disclosed in Disser, all of which fall under the scope of
the present invention.
[0029] The brush motor driver 108 is coupled to the SR motor driver
110. By providing a third supply bus 206, the brush motor 106 can
be driven by the increased voltage resulting in improved free speed
and thus, better response rate.
[0030] The brush motor driver 108 is coupled to the first and
second capacitor 208, 210 of the SR motor driver 110. The brush
motor driver 110 is adapted to supply current to the brush motor
106. The brush motor driver 110 includes first, second, third and
fourth switching elements or power FET transistors 248, 250, 252,
254 coupled to the brush motor 106. Preferably, the first, second,
third, and fourth switching elements are connected in an "H"
configuration as shown. The first switching element 248 is coupled
to the third terminal T3 by a ninth resistor 256 and to the fourth
terminal T4 by a fifth capacitor 258. The second switching element
250 is coupled to the fifth terminal T5 by a tenth resistor 260 and
to the sixth terminal T6 by a sixth capacitor 262. The third
switching element 252 is coupled to the seventh terminal T7 by an
eleventh resistor 264 and to the second supply bus 204 by a seventh
capacitor 266 and a twelfth resistor 268. The fourth switching
element 254 is coupled to the eighth terminal T8 by a thirteenth
resistor 270 and to the second supply bus 204 by an eighth
capacitor 272 and the twelfth resistor 268.
[0031] The first controller 112 uses conventional PWM control
techniques to control both motor current and motor voltage to
achieve desired motor performance.
[0032] The brush motor 106 operates between ground (the second
supply bus 204) and the third power supply voltage , B++. The
increased voltage improves the free speed and thus the response
rate of the brush motor 104.
[0033] With this invention has been described in reference to the
illustrated embodiment, it will be understood that various
modifications and design variations will occur to those skilled in
the art, and that drive circuits and controls incorporating such
modifications may fall within the scope of this invention, which is
defined by the appended claims.
* * * * *