Low Voltage Ride-Through Technology for Doubly-Fed Induction Generators

Low Voltage Ride-Through (LVRT) technology for doubly-fed induction generators (DFIG) serves as a critical mechanism in wind power systems for maintaining grid stability. During grid voltage dips, conventional DFIGs may disconnect from the grid due to rotor-side overcurrent or DC bus voltage fluctuations, leading to interruptions in wind farm power output. LVRT technology employs optimized control strategies to keep DFIGs connected during grid faults and enables rapid recovery to normal generation once voltage is restored. Implementation typically involves real-time monitoring of grid parameters and dynamic adjustment of converter controls through embedded algorithms.

In research conducted by Chi Yongning and his team at the Electric Power Research Institute, core LVRT challenges for DFIGs were extensively studied, focusing on dynamic current limiting control for rotor-side converters, intelligent switching strategies for crowbar protection circuits, and fast-tracking algorithms for grid synchronization signals. The integration of hardware protection with software control not only suppresses electromagnetic torque oscillations during faults but also enhances the transient response capability of wind turbine systems. Code implementation often includes PI controller tuning for current regulation and logic-based state machines for protection circuit activation.

This technology holds significant importance for modern power systems, particularly in scenarios with high penetration of renewable energy. It reduces grid disconnection incidents caused by grid disturbances, improves system fault tolerance, and provides reliable support for large-scale wind power integration. Looking forward, with advancements in flexible HVDC transmission and virtual synchronous generator technologies, LVRT performance for DFIGs is expected to undergo further optimization through adaptive control algorithms and predictive maintenance routines.