Power distribution and frequency regulation for PV-HESS based on VSG

The large-scale integration of photovoltaic (PV) generation introduces significant challenges to the stability of the power system due to its inherent randomness and volatility. This paper proposes a coordinated control strategy for the PV hybrid energy storage system (HESS) using a Virtual Synchronous Generator (VSG) to address this issue. First, a HESS is introduced on the inverter’s DC side, with a power distribution strategy designed to account for the differing characteristics of the battery and supercapacitor. Next, an adaptive control strategy is designed, using an improved particle swarm optimization algorithm to optimize the initial VSG parameters, considering their impact during the system’s dynamic process. The dynamic adjustment of the moment of inertia (J) and the damping coefficient (D) enhances the system’s frequency stability and fast frequency regulation capability. Finally, a simulation model for the grid connection of the PV HESS is developed using MATLAB/Simulink as the simulation platform. The simulation results show that the strategy effectively distributes power between the hybrid energy storage units and enhances the system’s frequency stability and dynamic response under typical operating conditions such as active power disturbances, load fluctuations, and sudden changes in grid frequency.