Switched Capacitor Based Transformerless Five-Level Inverter for the Minimization of Leakage Current in PV Systems

Abstract

This paper presents a cascaded five-level inverter which minimize the magnitude of leakage current flowing through the parasitic capacitance of the PV panel. The topology generates the five levels in the inverter output voltage with the help of two switched capacitors. The magnitude of voltage across the switched capacitors decides the modes of operation of the cascaded five-level inverter. The five-level topology can be operated in two modes: buck mode and boost mode. In the buck mode, the maximum value of the inverter output voltage is equal to the DC bus voltage. Whereas in the boost mode, the magnitude of inverter output voltage is equal to twice the DC bus voltage. Apart from the five-level generation, the inverter topology also maintains constant commonmode voltage (CMV) for both the modes of operation. As a result, the magnitude of commonmode current is also minimized. Complete details regarding the operation of five-level inverter, simulation results are presented in the paper.