Influence of the inverter characteristics on the iron losses in PWM inverter-fed induction motors

In this paper, the authors deal with the effects of inverter characteristics on iron losses in induction motors fed by pulsewidth modulation (PWM) controlled power converters. Laboratory tests based on no-load input power measurements were carried out and in order to avoid the influence of mechanical losses and rotor copper losses, which are difficult to be measured or computed, a special test bench with an unconventional test device was employed. In particular, the influence of the following inverter parameters are considered: modulation index; modulation waveform; and switching frequency. Complete experimental results are presented and discussed.