A Single-Stage Dual-Source Seven-Level Inverter for Grid Integrated Photovoltaic Energy Transfer System with MPPT

Abstract

A new seven-level multilevel inverter (MLI) with dual isolated input for grid-connected photovoltaic energy transfer system (PETS) is proposed in this paper. It has six unidirectional and one bidirectional semiconductor switches for realizing the seven-level output. The MLI finds application in photovoltaic (PV) energy transfer systems, where the requirement of two isolated DC sources is fulfilled by proper solar panel management. The bidirectional switch reduces the control overburden and improves circuit compactness as compared with the cascaded H-bridge MLI. The grid-connected PETS is designed to deliver the available PV power to load, connected in the distribution bus, as well as injects the remaining active power to the grid with a unity power factor (UPF). Moreover, PETS mitigates the reactive and harmonic demand of load irrespective of PV output and maintains the grid power quality within the IEEE-519 standard. The steady-state and dynamic performance of the proposed system is validated by using MATLAB/Simulink model, and the prototype for the MLI is developed and tested in the laboratory.