An Adaptive Control Strategy for a Better Performance of the Paralleled PV-BES-VSG Power System

The growing integration of renewable energy sources has led to the development of virtual synchronous generator (VSG) control as a way to enhance system stability and offer primary frequency regulation. These functions of VSGs usually rely on the photovoltaic (PV) system or battery energy storage (BES), which is equipped at the DC side of the system. However, due to differences in the initial state of charges (SoCs) and uneven power distribution, the SoCs of battery energy storage systems (BESs) may become unbalanced, posing risks to the healthy operation of BESs and the overall system reliability. To realize SoC balancing, an adaptive control scheme for a paralleled PV-BES-VSG power system is presented. The adaptive SoC balancing term is applied to the active power references based on a simple segmented quadratic function. The proposed control strategy can realize optimal operation of paralleled VSGs and reduce SoC imbalance at the same time. The effectiveness of the proposed control scheme is evaluated via a case study system consisting of two paralleled PV-BES-VSG units using Matlab/Simulink R2021a.