Bipolar switching waveform: Novel solution sets to the selective harmonic elimination problem

The problem of selective harmonic elimination pulse-width modulation (SHE-PWM) exhibits multiple sets of solutions. While these sets provide different solutions to the same problem, their harmonic performance varies greatly. Typical formulations to the problem have so far considered a quarter-wave symmetrically defined waveform in order to simplify the process of finding the required solutions, with great expense to the available solution space. In this paper, the three-phase half-wave symmetrically defined bipolar harmonic elimination is considered and analyzed in detail. The generalized formulation is also introduced and the multiple sets of solutions that exist are reported. An evaluation of the multiple sets with regard to the amplitude of the first significant harmonic and harmonic distortion factor is also performed. Selected simulation and experimental results are provided in order to verify the theoretical considerations.