VERFAHREN UND VORRICHTUNG ZUR STEUERUNG VON ELEKTRISCHEN MOTOR-GENERATOREN

摘要

A control system for an ac-powered electric motor-generator is arranged to control the voltage applied to stator coils in the motor-generator such that, during a low-speed regime, the power input is controlled by varying the time-averaged voltage applied to the motor within each half electrical cycle, while keeping substantially constant the phase of the applied voltage in relation to the rotational position of the motor-generator. In a high-speed regime, the power input is controlled by varying the phase of the voltage in relation to the rotational position of the motor-generator. In a first embodiment, control is effected, in the high-speed regime, purely by varying the phase of the voltage, and, in a second embodiment, control is effected at high-speed by varying both the phase of the voltage and also the time-averaged voltage applied within each half electrical cycle. In the low-speed regime, power input is controlled using asynchronous pulse width modulation, and, in the high-speed regime, when the time-averaged voltage is varied, control is effected using synchronized pulse width modulation and/or commutation width control.