Grid connected voltage source inverter control during voltage dips

This paper proposes a combined synchronization method for full scale converter of wind turbine (WT) aiming to ride trough balanced and unbalanced voltage dips due grid faults. A Kalman filter synchronization (KFS), capable extract the positive and negative sequence grid voltages, is designed to have a fast response to voltage disturbances. Then, a synchronous reference frame phase locked loop (SRF-PLL) is used as a inertia on the synchronization signals. As a result, the converter is able to provide faster response to voltage disturbances as voltage grid support even in the cases where the voltage falls to zero on the PCC. Also, and anti-windup strategy is introduced on the current control loop to avoid undesirable behavior during fault transitions. Simulation results demonstrate that the proposed combined synchronization method and the anti-windup control enhances the performance of grid connected converters during voltage dips situations and improves the low voltage ride trough capability of grid connected converters.