A Fault Ride through Scheme to Improve the Transient Stability of Wind Energy Systems

This paper proposes a novel fault ride-through (FRT) scheme for doubly fed inductor generator (DFIG)-based wind turbines. The approach combines an event-triggered sliding mode control (ETSMC) with a super-capacitor and a high-frequency magnetic linked dual active bridge converter (DABC). The design aims to mitigate grid fault induced transient instability by properly regulating the dc-link voltage to near its pre-fault level. The event-based SMC approach allows updating the control input only when certain stability conditions are violated, thus reducing the computational burden and mitigating the chattering effect typically present in standard SMC. The design is validated using a DFIG-based wind energy system connected to a feeder of a microgrid network. The obtained results confirm the performance and capability of the proposed scheme in providing necessary FRT support by effectively regulating the dc-link voltage and reducing converter loading during grid faults.