| 摘要 |
Unlike brush-type DC motors, a brushless permanent magnet DC motor has an impedance which is resistive at low rotational speeds and becomes increasingly inductive at higher speeds. Consequently, a control for a brushless permanent magnet DC motor must control both supply voltage and commutation angle in order to maximize motor performance. The simultaneous control of both supply voltage and commutation angle is difficult to achieve and requires complex circuitry. The present invention overcomes this problem by providing first means for developing a motor performance command signal representing a desired motor operational characteristics, second means for developing a motor feedback signal representing an actual motor operational characteristic, and means coupled to the first and second developing means for deriving the commutation angle command signal and the voltage command signal from the motor performance command signal and the motor feedback signal so that the motor operates with the desired operational characteristic.
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