A New Topology of Switched-Capacitor Multilevel Inverter With Eliminating Leakage Current

This paper proposes a new topology of the switched-capacitor multilevel inverter (SCMLI) for photovoltaics system, which can eliminate the leakage current. In the proposed topology, the capacitors are employed as a virtual DC power supply to boost the input voltage. Here, all capacitors are charging equal to DC source, thus, just one DC source is needed to achieve the staircase waveform. In this structure in order to make the negative levels, the capacitors are connected to the output in reverse polarity. Thus, the H-bridge circuit which is used in traditional SCMLI to build zero and negative voltage levels and leads a variable common mode voltage is removed. Due to the direct connection of the neutral terminal of the grid to the negative polarity of the PV; then this topology can eliminate the leakage current. In addition, the topology has an excellent ability to path the reverse current as well as an acceptable output waveform spectrum. The operating states of all components and loss calculations are analyzed and formulated accurately as well as simulated by using MATLAB-SIMULINK software. To confirm the performance of the proposed topology; a 500 W prototype is built and experimental results are presented.