The Life State Assessment And Research Of Power Modules In Wind Power Converters

The use of traditional fossil fuels has brought great pollution to the environment.At the same time,these energy reserves are limited and do not meet the sustainable development strategy of human society.Therefore,the development of new energy to alleviate energy pressure has become an urgent choice in today's society.After so many years of development,wind power generation has been considered the lowest development cost,the most mature,with large-scale development of renewable energy conditions.Therefore,the development of wind power,for the environment and social economy has important strategic significance.The power in the wind power generation system IGBT is the weakest link in all components,and the temperature is the key factor affecting its performance and life.When the junction temperature of the chip in the IGBT module is increased,the material coefficients of the modules are different And produce thermal stress,long-term under the impact of thermal cycling module will cause the material fatigue and aging,making the solder layer,aluminum wire break and fall off,and finally lead to module failure.In order to improve the reliability of wind power converter,this paper studies the life prediction method of IGBT in the side of wind power converter,and completes the evaluation of IGBT life by junction temperature.The main contents of the paper are as follows:?By analyzing the basic structure and working principle of the IGBT,the basic performance of the IGBT in the working state is studied,and the failure of the IGBT and the failure related to the chip are studied.The solder layer stratification and bonding are analyzed from the point of view of thermal stress The inherent physical mechanism of the warping caused by the warping of the cable reveals that the frequent temperature change is an important factor that causes the device to fail.It provides the theoretical basis for the construction of the thermal network model and the life prediction.? Considering the problem of the speed of the junction temperature,the power loss of the IGBT is analyzed by combining the device manual data.Based on the theory of electric heating,the thermal network model is constructed and the iterative algorithm is used to calculate the IGBT And finally,in order to verify the accuracy and reliability of the junction temperature iteration method,the results are compared with the results of the thermodynamically coupled model and the results of the method of measuring the junction temperature based on the fiber.?Through the analysis and research of the damage accumulation criterion and the rain flow algorithm,the rain flow statistical method is used as the data processing tool,the junction temperature is calculated by the junction temperature iteration algorithm,and the temperature load time series is extracted by the rain flow program to obtain the temperature load And it is believed that the IGBT module satisfies the Miner linear cumulative damage theory during the lifetime damage accumulation,and uses the Lesit life prediction model and the Miner to complete the IGBT lifetime prediction.