Comparison of different PWM-VSI fed 3 Φ IM based on modulation index and switching frequency

Abstract

The research in Pulse width modulation schemes has been intensive in the last couple of decades. PWM techniques have been used to achieve variable voltage and variable frequency in ac-dc and dc-ac converters. The inverter gives out better sinusoidal voltage and current, so the speed controls of machines are considered beneficial. But this is possible only when proper gating signals are provided to the inverters by PWM (Pulse Width Modulation) techniques. AC drives are more prominent than dc drives with Induction motors are mostly used in the industries. This paper discusses the performance analysis of the Voltage source inverter fed induction motor using PWM techniques on the basis of phase current of inverter, rotor and stator current, speed, electromagnetic torque developed and total harmonic distortion in line and phase voltage of the inverter for under modulation range. (MATLAB/Simulink) software has been used for the implementation of these techniques. The comparison of the main theories behind three-phase generation of SPWM, THIPWM, and SVPWM has been discussed. These three techniques are used to generate their respective output PWM signals, which are then compared, based on harmonic content and distortion using the total harmonic distortion (THD) measure of various output voltages, stator current and rotor current of the inverter feeding to the Induction Motor.