Ensuring Fault Ride Through for Wind Turbines with Doubly Fed Induction Generator: a Model Predictive Control Approach

This paper proposes a novel control strategy, based on Model Predictive Control (MPC), which ensures Fault Ride Through (FRT) for wind turbines with Doubly Fed Induction Generators (DFIGs). During large voltage dips, large currents are induced in the rotor that can destroy the rotor converter. The common approach used to protect the rotor converter is to disable the converter and to dissipate the rotor power via a crowbar circuit. This approach is currently not accepted by most grid codes which dictate that grid connected wind turbines should remain connected to the grid during severe faults with full control over their active and reactive power. The proposed strategy ensures FRT for DFIG grid connected wind turbines without using a crowbar and therefore meets recent grid codes requirements. This is achieved by using a Dynamic Series Resistance and an MPC controller incorporating most of the DFIG's constraints.