Power quality analysis of a PV fed seven level cascaded H-bridge multilevel inverter

Efficient DC to DC and DC to AC converters play a vital role in the reliable performance of standalone and grid connected photovoltaic systems. This paper deals with DC to AC conversion by a seven level cascaded H-bridge multilevel inverter for a standalone photovoltaic system. The PV fed seven level cascaded H-bridge multilevel inverter is analyzed in two ways: 1) with equal voltage sources as input to the H-bridges and 2) with unequal voltage sources as input. A comparative study of the total harmonic distortion reduction in the PV fed multilevel inverter system with and without equal voltage sources as input is carried out. It is observed that with unequal voltage sources, the total harmonic distortion is increased than that with equal voltage sources as input to the PV fed seven level cascaded H-bridge multilevel inverter. Further, the study attempts to show that with an LC filter at the output stage of the multilevel inverter, the total harmonic reduction is significantly reduced and the power quality of the PV fed multilevel inverter system is highly improved. Results are verified using simulations done in MATLAB/Simulink environment.