Analysis and Modeling of Low Voltage Ride Through for Permanent Magnet Direct-Drive Wind Turbines

As the individual capacity of wind turbine units continues to increase and the proportion of wind power in electricity supply grows, the interaction between wind turbines and the power grid becomes increasingly significant. When grid faults cause a drop in the voltage at the connection point of the generator, if a large-scale disconnection of wind turbine units occurs, it can lead to voltage and frequency collapse in the power system, posing a significant risk to the safety and stability of the grid. Therefore, the wind turbines must have low voltage ride through (LVRT) capability to ensure that they remain connected to the grid during grid faults and continue operating after the fault is resolved. In this paper, a simulation model of a permanent magnet direct drive wind turbine (PMDWT) under grid voltage dip fault is developed on MATLAB/Simulink platform. The dynamic response of the wind turbine under fault of the grid is investigated, and the effect of adding a crowbar circuit on the DC side on the fault response is compared and analyzed. The results show that the crowbar circuit can enhance the LVRT of the PMDWT.