A model for predicting voltage endurance of magnet wire film subjected to inverter PWM voltage waveforms with transient overshoots

A corona power aging model for predicting time-to-failure of magnet wire film under sinusoidal voltage stress is developed and validated by voltage endurance empirical test data. The life expectancy of magnet wire film insulation, when exposed to sinusoidally-modulated PWM inverter waveforms, is modeled. A quantitative analysis of the inverter waveform is developed which uses the amplitude, carrier frequency and modulation index of the PWM waveform, the transient energy due to waveform reflection and the corona inception voltage of the magnet wire film in question to describe the destructive electrical power available to degrade the insulation. The quantified corona-producing power in the inverter waveform is input to the corona power model of the magnet wire film in question to predict a life expectancy.