Research on Hybrid Energy Storage Control Strategy of Photovoltaic Microgrid Based on Virtual Synchronous Generator

The power of photovoltaic power generation is prone to fluctuate and the inertia of the system is reduced, this paper proposes a hybrid energy storage control strategy of a photovoltaic DC microgrid based on the virtual synchronous generator (VSG). Firstly, the VSG-based microgrid inverter is taken as the research object, then the working principle and control strategy are established and analyzed. Due to the uncertainty of photovoltaic output, the power distribution of the hybrid energy storage system (HESS) is the important link to stabilize DC bus voltage. This paper presents an improved first-order low-pass filter method to realize the power distribution, it can prevent the output of the supercapacitor from exceeding the limit, and improve the quality of the power supply. Finally, the simulation analysis is carried out through Matlab/Simulink. When the photovoltaic output fluctuates, the battery and supercapacitor can respond quickly and restrain the fluctuation of bus voltage, which verifies the effectiveness of the proposed method.