Common-mode Motor-surge-voltage Suppression Method

Abstract

On the AC motor drive system with the PWM inverter, a surge voltage appearing on the motor terminals (differential-mode motor-surge-voltage) is a serious problem. In order to reduce the surge voltage, a motor-surge-voltage suppression method using a surge suppression cable that the authors have developed has already been proposed. However, another type of motor surge voltage appearing between the motor windings and the motor frame (common-mode motor surge voltage) still remains. This paper presents a novel motor-surge-voltage suppression method using a surge suppression cable. The method enables suppression of both the differential-mode and the common-mode motor surge voltage, and its effectiveness is confirmed by the experiment. Moreover, a numerical analysis of the motor surge voltage is performed to obtain optimum parameters of the surge suppression cable for greater reduction of each.