Seven-Level Inverter with Reduced Switches for PV System Supporting Home-Grid and EV Charger

This paper proposes a simple single-phase new pulse-width modulated seven-level inverter architecture for photovoltaic (PV) systems supporting home-grid with electric vehicle (EV) charging port. The proposed inverter includes a reduced number of power components and passive elements size, while showing less output-voltage total harmonic distortion (THD), and unity power factor operation. In addition, the proposed inverter requires simple control and switching strategies compared to recently published topologies. A comparative study was performed to compare the proposed inverter structure with the recent inverter topologies based on the number of components in the inverter circuit, number of components per output-voltage level, average number of active switches, THD, and operating efficiency as effective parameters for inverter performance evaluation. For design and validation purposes, numerical and analytical models for a grid-tied solar PV system driven by the proposed seven-level inverter were developed in MATLAB/Simulink environment. The inverter performance was evaluated considering grid-integration and stand-alone home with level-2 AC EV charger (3-6 kW). Compared with recently published topologies, the proposed inverter utilizes a reduced number of power components (7 switches) for seven-level terminal voltage synthesis. An experimental prototype for proposed inverter with the associated controller was built and tested for a stand-alone and grid-integrated system. Due to the lower number of ON-switches, the inverter operating efficiency was enhanced to 92.86% with load current THD of 3.43% that follows the IEEE standards for DER applications.

Automated summary

This paper proposes a simple single-phase new pulse-width modulated seven-level inverter architecture for photovoltaic systems supporting home-grid with electric vehicle charging port. The proposed inverter requires simple control and switching strategies, and shows less output-voltage total harmonic distortion, unity power factor operation, and reduced number of power components compared to recently published topologies. An experimental prototype was built and tested, demonstrating an enhanced inverter operating efficiency with load current THD following IEEE standards for DER applications.