Reliability Assessment of Wind Power Converter Systems Based on Mission Profiles and Sub Module Life Correlations

The Wind turbine converters, as the core components of wind energy conversion systems, are crucial for the performance and reliability of the entire wind power generation system. Due to the uncertainty of wind speed and temperature, the converter load is in a state of fluctuation over the long term. Additionally, there is a correlation between the lifetimes of the submodules within the converter, making it difficult for traditional reliability assessment methods of power electronic equipment to accurately reflect the changes in the reliability of the converter. Therefore, a reliability assessment method for the wind power converter system that comprehensively considers the mission profile, and the correlation of submodule lifetimes is proposed. By establishing a wind turbine model and a thermal network model, combined with the analytical life model, the component lifetime of the module under the mission profile is calculated. Secondly, the Weibull distribution expression of the IGBT module component lifetime is obtained using the Monte Carlo method, and a dynamic Copula reliability calculation model for the series system is established, considering the correlation of submodule lifetimes, to assess the reliability of the entire wind power converter system. The study shows that the mission profile has a significant impact on the lifetime of the IGBT module, especially in high wind speed areas and extreme seasonal conditions, where the component lifetime is consumed more severely. Moreover, the constructed reliability calculation model accurately reflects the impact of the dynamic changes in the correlation of submodule lifetimes on the system’s reliability, verifying that considering the correlation of submodule lifetimes is essential for improving the accuracy of the system reliability assessment.