Real-Time Adaptive Selective Harmonic Elimination for Cascaded Full-Bridge Multilevel Inverter

Selective Harmonics Elimination is a high-efficiency modulation method for multilevel inverters that allows handling very high voltage applications. It eliminates the most significant harmonics and fixes desired fundamental component. The main issue of these techniques complex process to obtain appropriate switching-angles, being necessary calculate them offline, meaning if some disturbances occur, system will not be compensated. This article proposes real-time selective harmonic elimination single-phase cascaded inverter. control strategy maintains constant component output while removing its third, fifth, seventh order harmonics. switching-angles are dynamically adapted compensate variations in input load. done by obtaining virtual dynamic using Groebner basis, an adaptation Newton-Raphson method, implementing digital PI controller into dynamical model. adaptive technique validated experimentally 200 W, 9-levels Cascaded Full Bridge Inverter, canceling regulating components all tests. developed theory can or extended any inverter modulated elimination.