Study of the further reduction of shaft voltage of brushless DC motor with insulated rotor driven by PWM inverter

Authors succeeded in reduction of the shaft voltage of a motor with an insulated rotor driven by PWM inverter previously. This paper proposes a new method of further reduction of the shaft voltage of the motor with the insulated rotor. A non-grounding common-mode equivalent circuit of the motor is examined, and the effect of the further reduction by a new method is verified by calculation of the shaft voltage from the equivalent circuit and measurement of the shaft voltage of the motor.