Overvoltage analysis in inverter driven induction motors

The motor overvoltage in inverter driven induction motors is one of the most difficult current technical problem in variable speed system. The conducted electromagnetic interference (EMI) in inverter motor system is related to the inverter load which is the induction motor and cable. The analysis of the impedance characteristic of the motor and cable is fundamental in predicting the overvoltage phenomenon occurring at the motor terminals due to the parallel and series resonance. The overvoltage problem in variable speed system with high power motors and long cables can be predicted based on the motor and cable resonant frequency.