Enhanced Fault Ride-Through Control Strategy for Grid-Forming Wind Turbine Generators Based on Inertia-Synchronization

Using the grid-forming (GFM) control is an important trend for grid-connected wind turbine generators (WTGs) to enhance the grid stiffness with high renewable penetration. The inertia-synchronization control (IsynC), which utilizes the DC-link dynamics for grid-synchronization, is a promising method to realize GFM control of the WTGs without affecting the maximum power point tracking target. However, most of the existing literature focuses on the steady-state operation of the IsynC-based WTGs, and the grid fault ride-through strategies are not properly designed. Existing WTGs rely on the current control loop to limit the short-circuit current(SCC) during grid faults, which not only suffers from transient overcurrent, but also fails to fully utilize the fault voltage support ability. To solve this problem, a unified SCC controller, which consists of a voltage vector limiter and an adaptive virtual resistor, is proposed. On this basis, the grid voltage support capability of the IsynC-based WTG under fault conditions is enhanced by using the phase angle compensation. A comparative simulation is conducted in PSCAD/EMTDC to highlight the advantages of the proposed method. Finally, the effectiveness of the proposed strategy is verified through the hardware-in-loop (HIL) experiment.