A single-source photovoltaic power conditioning system using asymmetric cascaded multilevel inverter

This paper proposes a power conditioning system (PCS) for distributed photovoltaic (PV) applications using a hybrid asymmetric cascaded multilevel inverter with a single PV source. One of the main disadvantages of cascaded multilevel inverters in PV systems is the requirement of multiple isolated DC sources which leads to voltage unbalancing. The proposed PCS uses a single PV source with a flyback DC-DC converter to facilitate the reduction of the required DC sources and maintain voltage balance. The flyback converter is used to provide the input for low voltage H-bridge cell which processes only 20% of the total power. This helps to minimize the losses occurring in the proposed PCS. Furthermore, transient analysis and controller design for the proposed PCS in stand-alone mode of operation is presented. The feasibility of the proposed PCS has been tested using a 1kW hardware prototype and the obtained results are presented.