Random PWM Tecniques to Reduce Total Harmonic Distortion for Cascaded Three-Level Inverter Fed Induction Motor Drive

Abstract

The drive utilized for industrial and modern applications should use “spread spectrum” innovation known as Random PWM algorithms where acoustic noise emanating through the duck work is a very critically concerned. This paper illustrates three types of random PWM control algorithms with fixed switching frequency namely 1) Random modulating PWM 2) Random carrier PWM and 3) Random modulating-carrier PWM. The spectrum plots of the motor stator current demonstrate the strength and robustness of the proposed PWM algorithms. To affirm the proposed  algorithms, experimental tests have been conducted using dSPACE rt1104 control board  on a v/f control three phase induction motor drive fed by DC link cascaded multilevel inverter.