Impact Analysis of Double Fed Induction Generator Low-Voltage Ride-Through on the Switches of the Back-to-Back Converters

The expansion of wind energy conversion systems (WECS) is largely due to the advancements of power electronics devices, especially in terms of processed power levels as well as robustness in grid fault situations. In this sense, the power converters participate in the conditioning and control of the power delivered by the generators, requiring an analysis of the impact caused by situations that lead to possible damages or lifetime shortening due to abnormal operations. Considering this problem, in this paper a case study is performed in order to evaluate the impact of the double fed induction generator (DFIG) low-voltage ride-through (LVRT) on the switches of the back-to-back converters. For this purpose, modeling of the DFIG-based WECS has been performed in MatLab/Simulink, including a linear model for the converter switches, which are of insulated gate bipolar transistor (IGBT) type. The analysis presents the main impacts on the IGBT internal currents and voltages under symmetrical and asymmetrical grid faults, making possible to guide the application of methods and techniques to minimize the impacts caused to the converters.