Improved Low Voltage Ride-Through Control Strategy for Virtual Synchronous Generators Based on Deadbeat Predictive Current Control

Virtual Synchronous Generators (VSGs) facilitate grid-friendly distributed generation by emulating the inertia and damping of synchronous generators through inverter control. However, conventional VSG control lacks inherent low-voltage ride-though (LVRT) capability due to its voltage-source nature, leading to inadequate reactive power support during voltage sags and potential disconnection caused by overcurrent or instability. To address these challenges, this paper proposes an enhanced LVRT strategy for VSGs based on deadbeat predictive current control (DPCC), which has not been thoroughly reported. The approach employs a dual-current-loop scheme to regulate positive and negative sequence current precisely. By embedding DPCC into VSG control, this method avoids Proportional-Integral (PI) control tuning and DPCC parameter sensitivity, enabling faster, more accurate current control, thereby reducing fault-related current overshoot. Additionally, delay compensation is implemented to address control latency in practical systems. Based on these enhancements, a comprehensive VSG LVRT control scheme is developed, effectively mitigating overcurrent issues during grid faults, improving reactive power support and dynamic response, and ensuring robust operation under diverse operating conditions. Finally, simulation results validate the proposed method's effectiveness and correctness. In various voltage fault processes, the control time based on DPCC is approximately 0.04 s, and the THD remains below 1 %.