Single-Phase Multi-Level Inverter Suitable for Symmetrical and Asymmetrical Photovoltaic (PV) Applications

The demand for multi-level inverters has been increased over time. Less total harmonic distortion (THD) of output voltage, less voltage tension across switches, and low electromagnetic interference (EMI) are some of their favourable features. Among all the multi-level topologies, Cascade H-Bridge (CHB) inverters have more scalability, feasibility, and modularity; therefore, they are widely used. CHBs consist of full bridge converters required independent dc voltage sources that may be asymmetrical. In this paper, a SPWM cascade full-bridge single-phase 7-level inverter with optimized phase shift modulation is introduced. It uses capacitance voltage control and Genetic Algorithm for both symmetrical and asymmetrical conditions to alleviate harmonics and THD. MATLAB simulation is used to investigate the inverter performance under different operational conditions. In order to validate the simulation results, an experimental prototype of the inverter is implemented and practical results are presented.