Anti-Windup Action in Inverters Control of Distributed Generation Photovoltaic Systems

With the constant increase of the use of photovoltaic systems in Distributed Generation (DG), it becomes increasingly necessary to study strategies that guarantee not only that the systems remain connected during electrical faults, but also that shows a good post-fault recovery performance. In fault conditions, the operating limits of the converters are typically reached, which can cause the associated controllers to windup, which may affect the final performance of the system dynamics. This paper presents an anti-windup strategy for the inverter control loops with the focus on the DC link voltage and reactive power control performance. The anti-windup strategy was simulated for the case of a 500-kW photovoltaic generation system. The anti-windup actions showed to improve post-fault performance by reducing the recovery time and eliminating large peaking variations of voltage, current, and active power. Besides, it also showed to avoid large and sudden variations of both DC link voltage and MPPT control action after fault clearance.