Filter design of restraining over-voltage and bearing current in induction motor fed by PWM inverter

PWM-inverter-induction-motor system will produce the over-voltage at the motor side and the strengthening of bearing current. R-C filter installed at the motor side is an effective method for restraining the over-voltage and bearing current. The method of choosing the parameters of filter is presented in the paper. The results of the simulations and experiments displayed in the paper proved the validity of the above method. The paper presented a simulation procedure, which can consider the mutual inductance and the mutual capacitance of the cables, and the test results of impedance frequency characteristic of several sets of induction motor.