Enhancement of Frequency Regulation in AC Microgrid: A Fuzzy-MPC Controlled Virtual Synchronous Generator

Electrical energy storage (EES) with a virtual synchronous generator (VSG) method is used widely for power fluctuation compensation in renewable energy microgrid systems. In the traditional VSG method, the inertia moment and damping coefficients usually remain constant. When dealing with large load variations, this method may cause obvious system frequency deviations and exceed the standard limit (e.g., IEEE Std 1547-2018). This paper proposes a novel control method combining fuzzy control with a model predictive controller (MPC) to solve this problem. The new method was applied to VSG. The virtual inertia and damping coefficient of VSG are on-line adjusted by a fuzzy controller, so that the regulation capability of the swing equation can be substantially utilized. The optimal rated power of VSG was modified using the MPC method, which further strengthens the EES support for power needs. The system frequency performance can be enhanced effectively under joint control. The simulation and experimental results further demonstrated the effectiveness of the proposed method.