The distributed generation involving multiple photovoltaic sources and synthesizing high-quality ac voltage from those multiple dc sources are nascent research ambits. A host of multilevel inverters (MLIs) has been ascertained for performing above errand diligently, where the component count is obnoxious. The single phase seven-level inverter is an acquiescent compromise between the circuit complexity and the quality of the output. Further enhancement on the performance can be succored through optimizing dc link voltages and switching angles. This paper proposes a component count pruned MLI structure and also a refined genetic algorithm (RGA)-based optimization scheme for the computation of both dc link voltages and switching angles. Previous attempts for this problem have solved the switching angles with the objective of resulting minimum harmonic content in the staircase-shaped output voltage. The dc link voltage of each level is however assumed to be the same and constant. As an extension, RGA-based optimization of both dc link voltages and switching angles is triumphed. The harmonic profile of the proposed switching strategy is simulated and also corroborated by a hardware prototype. In practice, the proposed fundamental switched strategy is apposite, in which each dc voltage can be self-maintained and independently controlled. In addition, a method for designing the passive LC filter is also presented.
An Approach to Reduction of DC Voltage Ripple for Single-Phase PWM Converter.