Method for accumulated damage computation and life prediction of IGBT module used for electric car

Abstract

The invention relates to a method for accumulated damage computation and life prediction of an IGBT module used for an electric car. The method is characterized by comprising the following steps of setting whole-car parameters, relative parameters of the IGBT module, a road surface rolling friction coefficient and a drag coefficient; fitting a speed-junction temperature mean value relation curve and a speed-junction temperature fluctuation amplitude relation curve; obtaining running speed-time data and road surface gradient data of the electric car in real time; judging a car running speed change condition and a climbing condition and respectively computing the IGBT accumulated damage according to two modes in order to obtain total accumulated damage of the IGBT module; and predicting the lifetime and the life mileage of the IGBT module. According to the method, the direct link is established between the running condition of the electric car and the working condition of the IGBT module, the junction temperature data and the accumulated damage of the IGBT module are directly computed, the method can be used for researching the influence of factors, such as environment temperature, road surface gradient and running acceleration, on the service life of the IGBT module used for the electric car, and the method has wide application value.

Description

technical field [0001] The invention belongs to the technical field of reliability of power electronic devices, in particular to a method for calculating the cumulative damage degree of an IGBT module for an electric vehicle and predicting its life. Background technique [0002] As a green vehicle with no exhaust pollution and low noise, electric vehicles have good development prospects and have become a research hotspot in the field of new energy vehicles. With the rapid development of electric vehicle technology, the reliability and life of IGBT modules for electric vehicles have also attracted more and more attention. The source of IGBT module lifetime problems is material deformation caused by thermal stress. During the working or placing process of the IGBT module, the device loss and the ambient temperature change will cause the temperature change of the IGBT module. The thermal expansion coefficients of different layers of materials are different, and the temperatur...

AI Technical Summary

Problems solved by technology

[0003] At present, people are continuously researching on the life prediction of the IGBT module. The Chinese patent document with the application number CN201410393391.8 discloses a life prediction method of the power IGBT module. The ordered data is linearly fitted to obtain a continuous function, which is transformed into a sine quantity by Fourier transform. According to the circuit analysis method, the remaining life of the IGBT module is predicted. Since this method needs to destroy the packaging material during detection, it is difficult to implement , and the real-time detection accuracy cannot be guaranteed, so there is a certain deviation between the predicted value of the data processing model and the actual value, and the accuracy needs to be improved

[0004] To sum up, there is currently no IGBT module life prediction model for electric vehicles, which can establish a direct relationship between the operation of the electric vehicle and the working status of the IGBT module. It is necessary to directly measure the working status data of the IGBT module. The damage degree calculation and life prediction of the IGBT module in the application are not applicable

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