Selective harmonic elimination for modular 5-level MLC 2 topology based 7-level inverter by using genetic algorithms

In this paper, a modulation technique is proposed by combining selective harmonic elimination (SHE-PWM) and an optimized procedure with genetic algorithms (GA). The purpose is to mitigate individual harmonic components (5 th , 7 th , 11 th , 13 th ), reduce total harmonic distortion (THD%), control the amplitude modulation index (m a ) and frequency of the output fundamental component, while complying with the Brazilian grid codes. The GA determines three best fitted switching angles, by means of five evaluation or cost functions: one is proposed and other four ones are existing formulas obtained from the literature. Moreover, this optimized SHE-PWM based GA is applied to a proposed modular seven-level multilevel inverter (7-level MLC 2 ), which is based on the modular five-level MLC 2 (5-level MLC 2 ) topology. In this new circuit arrangement the neutral-point-clamped (NPC) technology based three-level switch leg, very well known in industry, is applied, and reduced number of switch count is achieved, when compared with classical NPC counterpart. Filterless operation and compliance with grid codes are evaluated by simulation results.