Power control strategy of PV system for active power reserve under partial shading conditions

摘要

To enable frequency support function in photovoltaic systems, it is a common practice to operate them in deloaded mode. In this mode, these systems are operated away from the maximum power point. Under uniform shading conditions, the power versus voltage curve has a single peak, therefore, the implementation of deloading control is simple. Most of the researchers have used uniform shading for deloading control. However, under partial shading conditions, the power versus voltage curve exhibits multiple peaks and the implementation of deloading control becomes complicated. In this paper, a deloading based power control strategy is proposed to generate an active power reserve in photovoltaic systems under partial shading conditions. The method avoids the blind scanning of the power versus voltage curve and scans only across the generated reference points. In this control, the system is deloaded by the proposed reserve generation algorithm and the deloading regions are such selected to cover a wide range of reserve values. The effective working of the control is tested with the help of simulations and experimental results.