Control strategy for improving the frequency response characteristics of photovoltaic and energy storage systems based on VSG control

Virtual synchronous generator (VSG) technology is an effective way to solve the problem of insufficient rotational inertia in renewable energy power systems, and it has significant advantages in improving the active frequency support capability of the power grid. However, due to the injection of virtual inertia, the response time and adjustment speed of the frequency modulation (FM) generator in the system are obviously limited. This paper proposes a frequency modulation control strategy with additional active power constraints for the photovoltaic (PV)-energy storage-diesel micro-grid system in the renewable energy power system. This strategy is based on VSG control, taking into account the impact of the output power of the PV-energy storage system on the system frequency change rate and diesel engine output power. Based on the proposed method, the system frequency of the PV-energy storage micro-grid can be flexibly adjusted, accelerating the system response time and adjustment speed. Finally, a four-terminal system model of VSG with PV-energy storage is constructed, and the effectiveness and practicability of the proposed FM control strategy with additional active constraints are verified by Matlab/Simulink and RT-LAB hardware in the loop experimental platform.