Analysis of Open-Circuit Fault Current of Wind Power Converters under Fluctuating Wind Speed

Abstract

With the depletion of fossil fuels and the worsening of environmental pollution, wind energy has garnered widespread attention as a renewable energy source. Direct-drive permanent magnet wind turbines offer advantages such as high efficiency and a gearbox-free design; however, their power converters are prone to failure under fluctuating wind speed conditions, making research into fault diagnosis particularly significant. This paper focuses on IGBT open-circuit faults in wind power converters. A simulation model of a direct-drive permanent magnet wind power system was established, employing grid voltage-oriented vector control to simulate three types of faults: single-tube, double-tube, and out-of-phase double-tube open circuits. Three-phase currents were used as feature signals to analyze waveform distortion patterns. By extracting quantitative indicators such as RMS value, THD, and three-phase asymmetry to compare fault characteristics, and using the Pearson correlation coefficient to analyze the correlation between wind speed and the amplitude of these characteristics, the results indicate that faults significantly increase current distortion and asymmetry, with distinct differences among the various fault types. Wind speed shows a weak correlation with the amplitude of these fault characteristics, and the characteristics demonstrate good stability and robustness. This study provides theoretical and data support for diagnosing converter open-circuit faults under fluctuating wind speeds.