Research On Accurate Junction Temperature Measurement Technology Of High Voltage And High Power IGBT Devices

High-voltage high-power IGBT device is a composite full-control voltage-driven power semiconductor device that can flexibly realize energy conversion,control and transmission.It is an indispensable key component in converter and DC breakers in flexible DC transmission systems.High-voltage high-power IGBT devices will have higher power density and higher reliability in the future.Accurate junction temperature measurement of IGBT devices is not only important for device condition monitoring and performance evaluation,but also critical for long-term operational reliability assessment and lifetime prediction.After decades of development,a lot of research work on junction temperature measurement has been done in domestic and foreign academia and industry,and proposed a variety of measurement methods,among which the voltage drop under low current is the best in all aspects,and most widely used.However,there are two sources of error in this method,which affect the junction temperature measurement accuracy,especially for high voltage and high power IGBT devices.One is the accuracy and equivalence of the calibration relationship,and the other is the determination of the initial junction temperature caused by the delay time.This paper focuses on the measurement error of the junction temperature measurement with the voltage drop under low current in high voltage and high power IGBT devices.The accurate measurement method is studied to improve the junction temperature measurement accuracy,which lays a foundation for reliability research and lifetime prediction model.In order to solve the problem of accuracy and equivalence of temperature calibration relationship,a uniform heating method based on electromagnetic heating is proposed.The uniform heating plates suitable for IGBT module and Press-Pack IGBTs are designed with the help of finite element simulation.The calibration relationship test bench is built to verify this method.In order to determine the initial junction temperature,the influencing factors of delay time are deeply studied through experiments,which provides a reference for selecting the appropriate delay time in the process of junction temperature measurement.The inversion calculation of the initial junction temperature is carried out by the root t method,and the influence of different factors on the inversion calculation accuracy under different package style is analyzed.Finally,the measurement error of the Press-Pack IGBTs is relatively small,which benefits from its excellent thermal characteristic of double-sided cooling.