Mitigation of bearing current and shaft voltage using five level inverter in three phase induction motor drive with SPWM technique

Abstract

Induction motor can be run as variable speed a. c. drive under the umbrella of recent technology advancements. Pulse width modulated (PWM) inverters are used to feed drive efficiently. Problems observed due to conventional inverter like: common mode voltage (CMV), total harmonic distortion (THD) in line voltage waveform, electromagnetic interference, inverter induced bearing current and shaft voltage owing to high rate of rise of voltage and more carrier frequency. These barriers are reduced using multilevel inverters. This paper proposed to minimize these shortcomings using a five level diode clamped sinusoidal pulse width modulation (SPWM) inverter. A model is simulated using MATLAB simulink for conventional and five level inverter fed induction motor using phase disposition (PD), phase opposite disposition (POD) and alternate phase opposite disposition (APOD) techniques.