Research on induction motor common-mode model in a PWM drive system

Pulse width modulated (PWM) inverter can generate common-mode voltage which can produce charge-discharge current at the distant of every insulated gate bipolar transistor (IGBT) high-speed switching. This current creates ground current escaping to earth through stray capacitors inside motors. The large ground current can create electromagnetic interference to the source and shorten the life of motor bearings by induced high shaft voltage, effect reliability of the whole system. To research the adverse effects of common-mode voltage and analyze the reducing effects expediently, common-mode induction motor model is founded based on analysis. Simulation and experiment results are presented to indicate the proposed model validity and practicability.