Surge Propagation of PWM-Inverter and Surge Voltage on the Motor

The use of PWM-inverter with high switching characteristics to provide the variable frequency supply to motors causes the overvoltage with steep-fronted waveform on the moter terminals.Insulation failure in motor winding can be caused by this steep-fronted transient voltage in inverter drive system. From the point of view of the wave propagation with skin-effect of the cable conductors, these phenomena are not reported in the papers. The main purpose of this paper is to describe the exact surge propagation into consideration of skin-effect of the cable conductors and the wave deflections at inverter and motor terminals.