Predicting the transient effects of PWM voltage waveform on the stator windings of random wound induction motors

In this paper, the effect of pulsewidth modulation (PWM) voltage waveform on the voltage distribution among the stator windings of random wound cage induction motors is studied. First, a method of estimating the high-frequency distributed-circuit parameters of the motor using finite-element analysis is described. From these parameters, an equivalent circuit is formed with the windings represented by partially distributed and partially lumped parameters. Using this equivalent circuit, the voltage distribution among the turns and coils of the motor are simulated using the SABER simulation package. Through simulation, the effect of rise time of the PWM wavefront on the voltage distribution is studied, and it is shown that the rise time of the wavefront has influence on the additional voltage stress on the line-end coil. In order to validate the simulation procedure adapted, the simulation results are compared with experimental results.