VSG Low Voltage Ride‐Through Control Strategy Based on Dynamic Impedance Current Limiting and Power Angle Coordinated Compensation

ABSTRACT

Virtual synchronous generators (VSGs) are one type of grid‐forming (GFM) inverter control technology. They have inertia and damping characteristics that can greatly improve grid inertia and voltage support. However, when serious grid faults occur, the power angle stability and fault current limitation of VSGs still face challenges. Existing studies on low voltage ride‐through (LVRT) control strategies often neglect the coupling mechanism between fault current and transient power angle. Therefore, this paper proposes a VSG LVRT control strategy based on dynamic impedance current limiting and power angle cooperative compensation. By decoupling and compensating for the power angle and current, the transient power angle oscillation of the VSG is eliminated. Furthermore, online virtual impedance reshaping breaks through the limitations of fixed parameters, maintaining the stability of fault current and power angle during a fault. In addition, this strategy can significantly shorten fault recovery time and is applicable to both symmetrical and asymmetrical short‐circuit faults. Simulation results show that the proposed LVRT control strategy can quickly and effectively suppress fault currents, maintain power angle stability, and verify transient stability under various fault conditions of the VSG.