Virtual Inductance and DC Boosting Control Based Low Voltage Ride-Through Method for Doubly-Fed Variable-Speed Pumped Hydro Storage Units

This paper proposes a novel low-voltage ride-through (LVRT) control strategy for doubly-fed variable-speed pumped hydro storage (VS-PHS) units. Unlike conventional LVRT approaches for DFIGs that mainly rely on crowbar circuits or virtual inductance control, the proposed strategy combines rotor-side virtual inductance with DC-link voltage boosting, fully leveraging the tolerance of pumped hydro units to elevated DC-link voltages during pumping-mode self-startup. In this way, it overcomes the inherent limitations of single virtual inductance control and extends the applicable range of virtual inductance control. A real-time digital simulation (RTDS) platform of a 300 MW VS-PHS unit is established to validate the method. Simulation results demonstrate that the proposed strategy not only suppresses rotor overcurrent more effectively than conventional demagnetization control but also provides reactive power support during faults, offering clear advantages over existing DFIG LVRT strategies. It can still operate safely and stably under severe voltage dips of up to 80%. This ensures secure and stable operation in both generating and pumping modes, across a wide speed range and under varying fault severities.