Mitigation of the adverse effects of PWM inverter through passive cancellation method

This paper proposes a PWM inverter fed ac induction motor drive system capable of suppressing all the adverse effects of PWM inverter to provide a robust control system. A passive EMI filter developed for this system is characterized by sophisticated connection of two small passive filters between inverter output and motor which can compensate for common mode voltages produced by PWM inverter and between motor neutral point and rectifier input which can suppress leakage current. As a result small passive filter with ability of reducing of all the adverse effects is approached. Experimental results show the reduction characteristics of the shaft voltage, bearing current, common mode current and leakage current