Active and Reactive Power Control During Unbalanced Grid Voltage in PV systems

Abstract

— This paper presents a control strategy for a grid connected photovoltaic (PV) system aiming to regulate the active and reactive power injected to the electric system during asymmetrical voltage faults. The active power reference is obtained from a Maximum Power Point Tracking (MPPT) algorithm. The proposed control strategy generates the required reference currents to be imposed by the grid-tied inverter from the desired active and reactive power and the measured supply voltage. The scheme is validated for a single stage PV system where the inverter currents are regulated via predictive control. Results showing the performance of the strategy are presented during unbalanced voltage sags and swells. Keywords—Solar power generation, MPPT, Current control, Power generation control, Voltage unbalance, Low-voltage ride through (LVRT)