Harmonic Intensity Reduction Technique for Three Phase VSI Drive through Double Randomness

Deterministic Pulse Width Modulation (PWM) methods are popular in industrial applications due to merits. However, the randomized PWM (RPWM) with its cleaner harmonic spectrum is gaining interest for industrial applications required to meet electromagnetic compatibility standards with almost all the earlier merits retained. The proposed Harmonic Intensity Reduction Double Randomness PWM (HIRDRPWM) technique is a hybrid RPWM, which attains the randomness in two ways. The first one is, in the pre-pulse generation stage, through the chaotic frequency generator, which generates a random frequency carrier (triangular) wave. Second randomness is, in post-pulse generation stage, by varying the position of the pulse. The competence in spreading the harmonic power of sinusoidal PWM (SPWM) and the HIRDRPWM is compared using simulation. The distribution of harmonic power in the output voltage of VSI with induction motor load is studied using the MATLAB software. The discussion includes Total Harmonic Distortion (THD) in output line voltage and the Harmonic Spread Factor (HSF).