Factors Affecting Losses in Induction Motors with Non-Sinusoidal Supply

This paper presents the results of an investigation into the factors affecting losses in induction motors operating with non-sinusoidal supply. It is well known that the losses in machines increase when a non-sinusoidal supply is used. However, the specific causes of the increase in loss and resultant techniques required to mitigate these losses are not fully known. The paper investigates the efficiency of an induction motor under different loading and supply conditions. As expected losses are a function of fundamental voltage waveform, load condition and PWM switching conditions. It is also shown that the additional stray loss caused by PWM supply (when compared to sinusoidal supply) is a function of these factors.