Optimal tracking for PV three-phase grid-connected inverter with LC filter

Abstract

The paper presents a simple yet accurate tracking control strategy for a three-phase grid-connected inverter with an LC filter. Three-phase inverters are used to integrate renewable energy sources such as photovoltaic (PVs) into the utility grid. The LC filters are integrated between the utility grid and the voltage source inverters for damping the high-frequency currents generated by renewable energy sources. Inverter control is a crucial component in guaranteeing that the quality of current injected into the grid complies with the power quality standards. Realizing the need for robust and adaptable control strategies that can handle the variability of PV systems, in this paper we employ a Linear Quadratic Regulator (LQR) tracking controller with an integral action to ensure zero tracking error. The efficiency of the proposed controller in tracking the grid power factor and active current variations is demonstrated via both simulation using MATLAB/SIMULINK and implementation using a laboratory-scale photovoltaic (PV) testbed that is established at the Hybrid Station Lab at Sultan Qaboos University.