Implementation of genetic algorithm-based SHE for a cascaded half-bridge multilevel inverter fed from PV modules

This paper presents both analysis and experimental verification of applying Selective Harmonic Elimination (SHE) technique for cascaded half-bridge multilevel inverters. The inverter units are fed from PV modules throughout step-down dc-to-dc converters to regulate the inverter input voltage. The inverter has to be asymmetric which allows more possibility to connect PV modules to get maximum possible number of voltage levels. Genetic Algorithm (GA) optimization technique based on SHE theory has been used to compute the optimum switching angles in order to eliminate the low order harmonics and minimize the total harmonic distortion. This can be achieved throughout utilizing a proper fitness function. A complete laboratory system fed from PV modules has been established based upon a DAQ controller. Results of both static and dynamic loads are obtained for single-phase 7-levels and 11-levels fed from 12 PV modules.