Multiple sets of solutions for harmonic elimination PWM bipolar waveforms: analysis and experimental verification

TLDR

Multiple sets of solutions for selective harmonic elimination PWM exist, and some may yield superior overall harmonic performance. This study proposes a minimization method to generate multiple sets of switching angles. The authors evaluate each set using a distortion harmonic factor based on the first two dominant harmonics, analyzing bipolar waveforms for single‑phase patterns that eliminate all odd harmonics and three‑phase patterns that eliminate only non‑triplen odd harmonics. Experimental results validate the theoretical predictions.

Abstract

Multiple sets of solutions for the selective harmonic elimination pulse-width modulation method for inverter control exist. These sets present an independent solution to the same problem but further investigation reveals that certain sets may offer an improved overall harmonic performance. In this paper, a minimization method is discussed as a way to obtain these multiple sets of switching angles. A simple distortion harmonic factor that takes into account the first two most significant harmonics present in the generated waveform is considered in order to evaluate the performance of each set. The bipolar waveform is thoroughly analyzed and two cases are considered; single-phase patterns which eliminate all odd harmonics and three-phase counterparts which eliminate only the nontriplen odd harmonics from the line-to-neutral pattern but such harmonics are naturally eliminated from the line-to-line waveform. Experimental results support the theoretical considerations reported in the paper.