Efficient switched-capacitor multilevel inverters for high-power solar photovoltaic systems

Abstract

Switched-capacitor multilevel inverters are suitable topologies for renewable and sustainable energy due to a low number of dc-link voltages. This article presents two extendable configurations for switched-capacitor multilevel inverters to be applied to solar photovoltaic systems. The first extendable configuration applies only to two DC supplies, and the number of levels is increased by connecting several capacitors in series, while the second extendable configuration uses a combination of DC sources and capacitors. The proposed inverters have a self-voltage balancing capability, and they reduce the voltage stress of switches, which leads to a reduction in the value of switching losses. The comparison indicates that both extendable topologies have advantages over most reported multilevel inverters, such as a low number of capacitors and semiconductors, low voltage stress, high boost factors, and a low-cost factor. An efficiency assessment is also presented, which shows the efficiency of the proposal is higher than recent topologies. The proposed inverter is tested and simulated for a high-power solar photovoltaic system that shows it possesses excellent performance with a high-quality output waveform. The functionality of the proposal is tested and evaluated by building a laboratory prototype.