Low-voltage ride-through capability improvement of Type-3 wind turbine through active disturbance rejection feedback control-based dynamic voltage restorer

Disconnections due to voltage drops in the grid cannot be permitted if wind turbines (WTs) contribute significantly to electricity production, as this increases the risk of production loss and destabilizes the grid. To mitigate the negative effects of these occurrences, WTs must be able to ride through the low-voltage conditions and inject reactive current to provide dynamic voltage support. This paper investigates the low-voltage ride-through (LVRT) capability enhancement of a Type-3 WT utilizing a dynamic voltage restorer (DVR). During the grid voltage drop, the DVR quickly injects a compensating voltage to keep the stator voltage constant. This paper proposes an active disturbance rejection control (ADRC) scheme to control the rotor-side, grid-side and DVR-side converters in a wind-DVR integrated network. The performance of the Type-3 WT with DVR topology is evaluated under various test conditions using MATLAB (R)/Simulink (R). These simulation results are also compared with the experimental results for the LVRT capability performed on a WT emulator equipped with a crowbar and direct current (DC) chopper. The simulation results demonstrate a favourable transient and steady-state response of the Type-3 wind turbine quantities defined by the LVRT codes, as well as improved reactive power support under balanced fault conditions. Under the most severe voltage drop of 95%, the stator currents, rotor currents and DC bus voltage are 1.25 pu, 1.40 pu and 1.09 U-DC, respectively, conforming to the values of the LVRT codes. DVR controlled by the ADRC technique significantly increases the LVRT capabilities of a Type-3 doubly-fed induction generator-based WT under symmetrical voltage dip events. Although setting up ADRC controllers might be challenging, the proposed method has been shown to be extremely effective in reducing all kinds of internal and external disturbances.