Indian Journal of Science and Technology

Abstract

Even the prime advantage of Sinusoidal Pulse Width Modulation (SPWM) technique is having an assortment of performances such as high output quality, less Total Harmonic Distortion (THD), low rating filtering requirements and linear control on fundamental component etc., the harmonic components of the output voltage are concerted around switching frequency and its integer multiples. These distinct dominant harmonics result mainly in torque ripples and acoustic noise in drives. These problems are mitigated by spreading the harmonic power in the output voltage through non-deterministic pulse width modulations. A chaos function based Random Pulse Width Modulation (RPWM) is proposed in this paper. A random frequency through chaotic number is generated first and then compared with the conventional sinusoidal reference function. The meticulous comparison of SPWM and the proposed Chaotic Carrier Sinusoidal Pulse Width Modulation (CCSPWM) is presented. The distribution of harmonic power in the output voltage of Voltage Source Inverter (VSI) with induction motor load is studied using MATLAB software. The discussion includes Total Harmonic Distortion (THD) in output line voltage, DC bus utilization and the Harmonic Spread Factor (HSF).

Keywords: Chaotic Carrier Sinusoidal Pulse Width Modulation (CCSPWM), Harmonic Spread Factor (HSF), Random Pulse Width Modulation (RPWM), Total Harmonic Distortion (THD)