Transient effects of PWM drives on induction motors

With the advances in semiconductor devices, adjustable-speed drives (ASDs) have become more prevalent than ever before in industrial and commercial processes. Many facilities are installing ASDs to improve the efficiency of their processes and to increase the control of their processes. While the effects of ASDs on the power system are well known, many engineers and systems integrators are not aware of the effects that ASDs can have on the motor that is driven by the drive. This paper describes the techniques used to measure, analyze and simulate the problems associated with the use of pulsewidth modulation (PWM) ASDs to drive induction motors. Measures to mitigate these problems are also discussed. The electromagnetic transients program (EMTP) is used to simulate the phenomena, compare results against measurements, and evaluate mitigation techniques.