A Multi-Objective Coordinated Fault-Riding Strategy for Grid-Forming Converters

Abstract

To address the issues of excessive fault current, insufficient voltage support, and frequency oscillations in grid-forming converters during power grid short-circuit faults, this paper establishes a fault ride-through test model based on the principle of impedance voltage division and analyzes the fault transient characteristics of a virtual synchronous generator (VSG). A fault-voltage support strategy integrating reactive power injection and internal electromotive force (EMF) regulation, together with an active power regulation method based on current-limiting constraints, is proposed. An adaptive inertia-damping mechanism is introduced into the control loop, which dynamically regulates the virtual inertia and virtual damping coefficients to suppress frequency fluctuations during fault engagement and clearance. The rationality of the system parameter configuration is verified through impedance modeling, and experimental validation is conducted using the RT-LAB hardware-in-the-loop (HIL) platform. The results demonstrate that the proposed multi-objective coordinated control strategy enables the converter to remain connected to the grid during faults. The steady-state fault current meets the limit requirements, the frequency response is stable, and reactive power support complies with the national standard. This study provides theoretical support for fault ride-through of grid-forming converters in power systems with a high proportion of power electronics.