A Novel Common-Ground Nine-Level Quadruple Boost Inverter Based on Switched-Capacitor

Multilevel inverters have been popular in photovoltaic applications because of lower total harmonic distortion, higher power quality and lower switching stress. This letter proposes a novel switched-capacitor common-ground nine-level inverter with quadruple voltage boosting ability and low voltage stress. Based on switched-capacitor charging in parallel/ discharging in series with the input voltage source, the capacitor voltage can be stabilized at desired value without additional control, allowing self-voltage balancing of capacitors. In addition, due to the boost ability of switched-capacitor structure, the inverter can achieve quadruple boost output. Since the neutral point of the grid is directly connected to the negative terminal of the photovoltaic panels, so the leakage current is eliminated completely. A comparison is also made in terms of the number of elements, voltage gain factor and capacitor voltage. Finally, a prototype is built and experimental results are presented to confirm the performance of the proposed topology.