Method and device for controlling an AC motor

摘要

The invention relates to a method and a device for controlling an AC motor. In the event of an AC motor being driven in a controlled manner by an output signal from a converter using pulse amplitude modulation (PAM), a pulse width modulation controller (PWM) is provided in addition to the pulse amplitude modulation controller. While the AC motor is being started, both the pulse amplitude modulation controller and the pulse width modulation controller are operated in order to suppress the starting current. The pulse width modulation controller is open circuited approximately at the point in time when the starting phase of the AC motor comes to an end, and only pulse-amplitude modulation control is still carried out. <IMAGE>