Modified DFIG Convertor Control Strategy for High Voltage Ride Through

Abstract

Currently, wind power penetration is increased, and chain failures caused by DC blocking expose wind turbines to greater risk of high voltage ride-through (HVRT). In this paper, a modified HVRT strategy for rotor-side and grid-side converter of doubly-fed induction generators (DFIGs) is proposed. A reactive power control strategy based on voltage bias is proposed for the grid-side converter (GSC) to maintain the DC-link voltage. To support the recovery of grid voltage after voltage dip, a modified control strategy for DFIG’s rotor side converter is proposed. A model of the grid-connected wind farm is built in MATLAB/Simulink to test the feasibility of the proposed method. Without adding additional hardware, the proposed strategy can ensure that the DC-link voltage does not exceed the limit during HVRT process of the wind turbine, and DFIG can absorb a certain amount of inductive reactive power to support the grid voltage recovery. Simulation results show that the proposed method improves the high voltage ride- through capability of DFIG under various operating conditions.