Control system for switched reluctance motor
First Claim
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1. A closed-loop control system for a multiphase switched reluctance motor in which the current of each stator phase is controllably switched on and off in synchronism with rotor position, comprising:
- encoder means for generating rotor position information signals;
speed computation means for generating an actual speed signal from said rotor position information signals;
feedback control means for receiving and processing said actual speed signals from said speed computation means and for receiving an operator command to generate a current command, a turn-on angle signal and a pulsewidth angle signal;
angle control means connected to said feedback control means for receiving and converting said turn-on angle signal and pulsewidth angle signal into a pulsetrain of conduction angle pulses synchronized with rotor position for each stator phase, the pulsetrains for the different stator phases being mutually phase-shifted; and
current control means for receiving and comparing the current command from said feedback control means with the actual current of each stator phase to generate a current magnitude limiting signal for each stator phase, said current control means also receiving the pulsetrains from said angle control means, said current control means having coupling means for combining the pulsetrain for each phase with the current magnitude limiting signal for said each phase, respectively, to generate a stator current control pulsetrain for each of said stator phases.
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Abstract
A programmable, closed-loop four quadrant control system for a switched reluctance motor employs feedback control, angle control and current control. The feedback control can be implemented with a speed feedback loop and/or a torque feedback loop. The angle control digitally synchronizes stator phase current pulses with rotor position, and the current control acts as a chopping or bang-bang controller to limit magnitude of the stator phase current pulses.
101 Citations
48 Claims
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1. A closed-loop control system for a multiphase switched reluctance motor in which the current of each stator phase is controllably switched on and off in synchronism with rotor position, comprising:
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encoder means for generating rotor position information signals; speed computation means for generating an actual speed signal from said rotor position information signals; feedback control means for receiving and processing said actual speed signals from said speed computation means and for receiving an operator command to generate a current command, a turn-on angle signal and a pulsewidth angle signal; angle control means connected to said feedback control means for receiving and converting said turn-on angle signal and pulsewidth angle signal into a pulsetrain of conduction angle pulses synchronized with rotor position for each stator phase, the pulsetrains for the different stator phases being mutually phase-shifted; and current control means for receiving and comparing the current command from said feedback control means with the actual current of each stator phase to generate a current magnitude limiting signal for each stator phase, said current control means also receiving the pulsetrains from said angle control means, said current control means having coupling means for combining the pulsetrain for each phase with the current magnitude limiting signal for said each phase, respectively, to generate a stator current control pulsetrain for each of said stator phases. - View Dependent Claims (2, 3, 4, 5, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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- 6. The control system of claim wherein the current control means comprises a bang-bang current controller.
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18. A method of controlling a multiphase switched reluctance motor in a closed loop fashion which facilitates motor operation in four quadrants, comprising the steps of:
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(a) continually comparing one of; 1. actual motor speed with commanded motor speed; 2. actual motor torque with commanded motor torque; and 3. actual motor speed and torque with commanded motor speed and torque, to generate a feedback current command; (b) generating mutually phase-shifted pulsetrains for the respective stator phases of said motor, each of said pulsetrains comprising conduction angle pulses synchronized with the rotor position of said motor and coordinated with an inductance profile of the motor in accordance with a selected quadrant of motor operation; (c) switching on and off the actual current in each respective stator phase of the motor in correspondence with the pulsetrain for said respective phase; (d) limiting amplitude of the actual current for each said respective phase to a value substantially within a hysteresis band surrounding the current command for speeds below a base value; and (e) Limiting peak amplitude of the actual current in each said respective phase to a maximum of said hysteresis band when the speed of the motor exceeds said base speed.
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19. A feedback control for a switched reluctance motor, the motor having multiple stator phases to be sequentially switched on and off in synchronism with rotor position by phase current pulses, the magnitude, turn-on angle and pulsewidth angle of said phase current pulses being determined by the feedback control so as to facilitate smooth operation throughout the full speed range of the motor in four quadrants of operation, the feedback control comprising:
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processing means for receiving and closed-loop processing an actual motor speed signal and an operator command to generate a current command, the current command serving to limit the magnitude of actual phase current; angle computation means for generating a turn-on angle signal and a pulsewidth angle signal or said phase current pulses; and coordination means for coordinating the turn-on angle signal and the pulsewidth angle signal with a particularly quadrant in which the motor is operating. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
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36. A method of controlling a multiphase switched reluctance motor in a closed-loop fashion which facilitates motor operation in four quadrants, comprising the steps of:
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(a) continually comparing one of; 1. actual motor speed with commanded motor speed; 2. actual motor torque with commanded motor torque; and 3. actual motor speed and torque with commanded motor speed and torque, to generate a feedback current command; (b) generating a turn-on angle signal which for at least one quadrant of motor operation is a function of said feedback current command; (c) generating a pulsewidth angle signal which for at least one quadrant of motor operation is a function of said feedback current command and actual motor speed; and (d) processing said current command, turn-on angle signal and pulsewidth angle signal to generate switched reluctance motor stator phase current pulses.
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37. A digital angle control for a switched reluctance motor, the motor having multiple stator phases to be sequentially switched on and off by current pulses applied to the respective stator phases, the digital angle control controlling timing of said current pulses for application to the respective stator phases, said control comprising:
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signal processing means for receiving and processing rotor position information signals to generate a multiphase sync pulsetrain and individual stator phase sync signals for the respective stator phases; PLL means for receiving said multiphase sync pulsetrain and generating a resolution signal therefrom, the resolution signal being a phase-locked, frequency-multiplied derivative of said multiphase sync pulsetrain; and programmable counter means for receiving a turn-on angle signal, a pulsewidth angle signal, said resolution signal and the individual stator phase sync signals and generating a train of current pulses synchronized with rotor position for each of said stator phases, each of said current pulses having a turn-on angle and pulsewidth corresponding to said turn-on angle signal and pulsewidth angle signal, respectively. - View Dependent Claims (38, 39, 40, 41, 42, 43, 44, 45, 46, 47)
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48. A method of synchronizing phase current pulses applied to multiple stator phases of a switched reluctance motor, with rotor position, comprising the steps of:
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generating rotor position information signals representative of instantaneous rotor position with respect to each stator phase; processing the rotor position information signals to generate a multiphase sync pulsetrain and to generate individual stator phase syne signals for the respective stator phases; generating a resolution signal from said multi-phase sync pulsetrain, the resolution signal being a phase-locked, frequency-multiplied derivative of said multiphase sync pulsetrain; and employing said resolution signal and the individual stator phase sync signals to convert a turn-on angle signal and a pulsewidth angle signal into corresponding current pulses synchronized with rotor position for each of said respective stator phases.
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Specification