Modeling, simulation and control of three-phase three level multilevel inverter for grid connected photovoltaic system

Abstract

This paper presents a control for a three phase three-level neutral point clamped inverter (NPC) for grid connected photovoltaic (PV) system. The maximum power point tracking (MPPT) is capable of extracting maximum power from the photovoltaic (PV) array connected to each DC link voltage level. The MPPT algorithm is solved by Perturb&Observe. method. The MPPT system is integrated with the DC-link controller so that a DC DC converter is not needed and the output shows accurate and fast response. Synchronous Reference Frame (dq) Control Strategy is used for grid-connected PV system so that PI controllers are used to control easily DC-link voltage, active and reactive currents. The validity of the system is verified through the simulations with MATLAB/Simulink.