Reduction of Total Harmonic Distortion in Nine Phase Induction Motor Drive with Third Harmonic Injection Pulse Width Modulation Technique

Abstract

Industrial applications demands high torque and long life span motor drives. Three phase motor drives have limited torque density hence Multiphase motor drives are better solutions for high torque density and heavy loads. In this work a Nine Phase Inverter is designed to drive Nine Phase load. The loads used in the industries almost nonlinear loads like motors. Therefore,due to these nonlinear loads additional harmonics induced at the output of the nine phase Inverter Drive with fundamental frequency. These harmonics are higher than fundamental frequencies and cause Total Harmonics Distortion(THD) which increases the rms current and generates more heat in the load.Many techniques are used to suppress the harmonics to minimize the heat in the load. A new technique is employed in this work to minimize THD by constructing THIPWM (Third Harmonics Injection Pulse Width Modulation) technique to overcome the low performance of a conventional PWM (pulse width modulation) control. In this work, the desired output voltage is achieved by comparing the desired sinusoidal waveform (modulating signal) with a high frequency triangular waveform (carrier signal). The harmonics and THD obtained using PWM and THIPWM is compared using Matlab/Simulink