Simultaneous total harmonic distortion minimization and selective harmonic elimination: Combining the best of both worlds

Power electronic converters for medium and high power / voltage applications employ low frequency fundamental switching that is dictated by the necessity to minimize switching losses. There are two major approaches to switching angles determination - Total Harmonic Distortion (THD) minimization and Selective Harmonic Elimination (SHE). For the THD minimization, the switching angles are found so as to assure minimum THD without taking any care of frequency spectrum. For the SHE approach, all degrees of freedom due to available amount of switching angles are spent on elimination of certain low order harmonics. The basic idea of the suggested combined approach consists in spending some degrees of freedom on certain harmonics elimination and using the rest for minimizing THD. This generalized problem formulation includes classic minimal THD and SHE problems as special cases.