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 the inverter characteristics on the iron losses increment in induction motors fed by PWM controlled converters. Laboratory tests based on no-load input power measurement were carried out and, in order to avoid the influence of mechanical losses and rotor copper losses which are difficult to measure or compute, 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