Low Voltage Ride-Through Capability Based Dynamic Voltage Restorers for DFIG Wind Turbine System

This paper proposes a low-voltage ride-through (LVRT) scheme for a doubly-fed induction generator (DFIG) wind turbine (WT) system. With the proposed method, dynamic voltage restorer (DVR) in which its DC-side is connected at the DC bus of the back-to-back converters, instead of being provided by conventional diode rectifier have been applied, enables to compensate a voltage response of the system during the grid faults and to reduce the capital cost. Also, the reactive power from both grid-side converter (GSC) and DFIG is exploited to control for grid voltage recovery under the grid fault, and thus, reduce the capacity of the DVR. Moreover, to protect the DC capacitor from its overvoltage, a braking chopper has been employed. The effectiveness of the proposed methods is verified by the simulation results for the 2 [MW]-DFIG wind turbine system under fault grid voltage conditions.