LAUSR

Multilevel inverters (MLIs) featuring reactive power ability and common-ground (CG) become much popular in transformerless grid-tied photovoltaic (PV) applications. A switched-capacitor (SC) based five-level transformerless inverter configuration is thus proposed in this paper, which requires only six switches, one diode, three capacitors and one input dc voltage supply. Notably, only four power switches are operated in high frequency, thus, the switching losses are reduced. Moreover, the presented topology can effectively tackle the leakage current problem using a common-ground architecture. A multicarrier phase disposition pulse-width modulation (PD-PWM) strategy is employed to achieve reactive power regulation and SC voltage self-balancing. To achieve the neutral point voltage balance of the presented five-level inverter, a simple closed-loop voltage-balancing control method is proposed. The operation principles with modulation strategy, voltage self-balancing of SC are discussed in depth. Comparisons between the proposed and the state-of-the art MLIs are presented in detail. Finally, experimental tests on a single-phase 1.1-kW prototype validate the appropriate performance of the proposed inverter.