Decoupled Active and Reactive Power Predictive Control for PV Applications Using a Grid-Tied Quasi-Z-Source Inverter

Abstract

This paper proposes a predictive power control algorithm that decouples active and reactive power for grid integration of photovoltaic (PV) systems using a quasi-Z-source inverter. This is important to meet the emerging smart inverter requirements for grid interconnection. The proposed controller uses model predictive control framework to ensure that the maximum available power is harvested from the PV array and that the active and reactive power injected into the grid is controlled to compensate reactive power required by local loads and as need to ensure stable operation of the grid at the point of common coupling. Thus, a power electronics interface is proposed to integrate the PV array to the grid and to work as a reactive power compensator simultaneously. A robust technique is proposed to regulate the impedance network voltage and current according to the maximum operating point of PV panels and grid voltage/current requirements. The proposed controller features a simple structure suitable for practical implementation, fast-dynamic response under changing sky condition, and negligible tracking error in steady state for decoupled active and reactive power control in a typical distributed generation systems. The performance of the proposed controller is verified experimentally; the grid-side power quality analysis is provided and evaluated according to IEEE-519 standard.