Loss Distribution of Three-Phase Induction Motor Fed by Pulsewidth-Modulated Inverter

This paper deals with the loss distribution in a three-phase induction motor fed by a pulsewidth-modulated (PWM) inverter. The copper losses in the stator winding and rotor conductor bar, and iron loss except for mechanical and stray load losses, are computed by the variable time-stepping finite-element method (FEM) considering the switching action of the PWM inverter. The iron loss is evaluated by the frequency analysis of the magnetic flux density distribution using discrete Fourier transforms (DFT) and iron loss curves, which are provided by the manufacturer. Simulation results by the presented method are verified by the experiment results. Finally, the loss distribution of the PWM inverter type three-phase induction motor is compared with that of the conventional three-phase induction motor that is directly fed by the sinusoidal three-phase voltage source without any control devices.