A power conditioner for a grid-connected photovoltaic generator based on the 3-level inverter

Abstract

This paper describes the fundamental design of a novel power conditioner for medium size photovoltaic generators. The proposed conditioner employs several poles of the 3-level inverter, which, configured through current sharing reactors, can provide a multi-level voltage. The conditioner provides maximum power point tracking and power factor correction by direct control of the instantaneous value of the inverter output current. A PWM-gate control is derived which utilizes the multilevel form of the output voltage and effectively increases the switching frequency of the inverter without increasing the switching frequency of its valves. Simulation studies in the paper verify the steady state and transient performance of the proposed conditioner. The simulation results show that implementation of the proposed design could significantly improve the power quality of photovoltaic generators.