Simultaneous Selective Harmonic Elimination and Total Harmonic Distortion minimization for a single-phase two-level inverter

To minimize semiconductor switching losses, power converters for medium and high power / voltage applications utilize low frequency synchronous fundamental switching. The two major approaches to switching angles determination are Selective Harmonic Elimination (SHE) and Total Harmonic Distortion (THD) minimization. For the THD minimization, the switching angles deliver minimal THD value without taking care of frequency spectrum. For the SHE approach, all degrees of freedom are spent on elimination of certain low order harmonics. It was recently suggested to combine both approaches that means spending some degrees of freedom to eliminate low frequency harmonics and the rest to minimize THD. This way, a generalized problem formulation includes classic minimal THD and SHE problems as special cases. The paper presents combined SHE and THD minimization results for a two-level single-phase inverter with different amount of switching.