Analysis and experimental verification for multiple solutions of bipolar SHEPWM waveforms applied in control system of induction machines

Since selective harmonic elimination PWM (SHEPWM) was proposed, the calculation of switching-angle curves has been a hot research point. Up to now, many approaches have been applied and multiple solutions of SHE equations have been obtained. Multiple sets of switching-angle curves provide SHEPWM strategies, which are often adopted in the control system of induction machines for railway driving, more options. This paper aims to analyze harmonic characteristics of multiple solutions and shows experimental results to verify their difference.