Efficiency optimization control for permanent magnet motor drive
First Claim
1. Apparatus for driving an electric motor comprising:
- an inverter providing switched electrical power to the motor from an electrical supply voltage source;
a controller providing gating signals to the inverter to control the switches of the inverter;
the controller receiving a torque command signal corresponding to a desired motor torque to control the motor speed;
the controller further receiving a current feedback signal related to the current supplied to the motor by the inverter;
the controller including a speed and rotor angle estimator for estimating the speed of the motor and the rotor angle of the motor and providing an estimated speed signal and an estimated rotor angle signal;
further comprisinga vector demodulator receiving the current feedback signal and for controlling the gating signals to achieve a desired motor speed corresponding to the torque command;
further comprising an optimization control for providing a rotor angle correction signal, said rotor angle correction signal being summed with the estimated rotor angle signal to provide a corrected estimated rotor angle signal to reduce an angle error in said estimated rotor angle signal, the corrected estimated rotor angle signal being provided to said vector demodulator to reduce the torque command signal and the current supplied by the inverter to the motor while achieving the desired motor torque, thereby improving efficiency of operation of the motor.
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Accused Products
Abstract
A method and system for modifying an estimated rotor angle for improved efficiency in a PMSM drive system. A module monitors a run command, a torque command, and an estimated speed; and in response thereto, generates an output correction angle for modifying the estimated rotor angle. The output correction angle may be added to the estimated rotor angle. The output correction angle may be generated only for predetermined conditions of said run command, torque command, and speed. In particular, the output correction angle may be generated (1) when the run command is asserted, (2) when the torque command is above a predetermined level, and (3) when variations in the speed are within predetermined limits.
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Citations
22 Claims
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1. Apparatus for driving an electric motor comprising:
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an inverter providing switched electrical power to the motor from an electrical supply voltage source; a controller providing gating signals to the inverter to control the switches of the inverter; the controller receiving a torque command signal corresponding to a desired motor torque to control the motor speed; the controller further receiving a current feedback signal related to the current supplied to the motor by the inverter; the controller including a speed and rotor angle estimator for estimating the speed of the motor and the rotor angle of the motor and providing an estimated speed signal and an estimated rotor angle signal;
further comprisinga vector demodulator receiving the current feedback signal and for controlling the gating signals to achieve a desired motor speed corresponding to the torque command; further comprising an optimization control for providing a rotor angle correction signal, said rotor angle correction signal being summed with the estimated rotor angle signal to provide a corrected estimated rotor angle signal to reduce an angle error in said estimated rotor angle signal, the corrected estimated rotor angle signal being provided to said vector demodulator to reduce the torque command signal and the current supplied by the inverter to the motor while achieving the desired motor torque, thereby improving efficiency of operation of the motor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for driving an electric motor comprising:
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providing switched electrical power from an inverter to the motor from an electrical supply voltage source; providing gating signals to the inverter to control the switches of the inverter; receiving a torque command signal corresponding to a desired motor torque to control the motor speed; further receiving a current feedback signal related to the current supplied to the motor by the inverter; estimating the speed of the motor and the rotor angle of the motor and providing an estimated speed signal and an estimated rotor angle signal;
further comprisingproviding the current feedback signal to a vector demodulator and controlling the gating signals to achieve a desired motor speed corresponding to the torque command; further comprising providing a rotor angle correction signal, said rotor angle correction signal being summed with the estimated rotor angle signal to provide a corrected estimated rotor angle signal to reduce an angle error in said estimated rotor angle signal, the corrected estimated rotor angle signal being used to reduce the torque command signal and the current supplied by the inverter to the motor while achieving the desired motor torque, thereby improving efficiency of operation of the motor. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification