A Common Mode Equivalent Circuit Usable for Calculating Common Mode Current and Bearing Current of Induction Motor Driven by PWM Inverter

Abstract

In this paper, a common mode equivalent circuit usable for calculating common mode current and bearing current of a 0.75kW induction motor driven by PWM inverter is proposed at first. Next, motor capacitance formulas are presented and those values are calculated for the motor, and these values are compared with experimental results. Calculated common mode impedance versus frequency based on proposed circuit is also compared with that of experimental results, and both characteristics are agree well. Finally, the validation of the proposed common mode equivalent circuit is demonstrated by the fact that the proposed circuit reproduce the experimental results of common mode current and bearing current.