Research On Power Cycle Test Of IGBT Module For Electric Vehicle

IGBT devices are one of the core components in electric vehicles.The life of IGBT devices is directly related to the life of electric vehicles.Therefore,testing the long-term life of IGBTs has become an indispensable part of electric vehicles.Due to design requirements,the service life of IGBTs tends to be more than 20 years.Therefore,power cycle experiments are required to perform power aging experiments on IGBT devices.Accelerated aging experiments are carried out under equivalent power cycle experimental conditions to estimate the service life of IGBT devices in practical applications..The power cycle experiment mainly tests the package reliability of the IGBT device,and reproduces the two main failure modes of the IGBT device package by controlling the experimental conditions:bond wire failure and solder layer aging.The key of the experiment is to control the fluctuation range of the junction temperature and the maximum temperature,and obtain the experimental life under different conditions,thereby obtaining the lifetime of the IGBT device.In this paper,a power cycling device capable of accommodating multiple IGBT devices is designed.At the same time,the key thermal resistance test in the power cycle is integrated into the device,which reduces the error caused by the traditional thermal resistance test method.The control system,test fixture,water cooling system,protection circuit and measurement program are built on the hardware to ensure the stability and measurement accuracy of the system.Through the NI measurement system for measurement,a variety of controllable parameters have been added to meet the measurement of various experimental parameters.The overall system guarantees a water temperature deviation of 0.5℃ and a voltage deviation of 2 mV,achieving a higher precision measurement.The power cycling experiment was carried out on three electric vehicle modules using the experimental platform.At present,the experimental platform is reliable and trouble-free to operate hundreds of thousands of times.After the failure of the IGBT device,the failure analysis of the IGBT device is performed by using an ultrasonic scanner to verify the IGBT device.The failure mode proposes improvement measures for the weakness of IGBT devices under the severe conditions of electric vehicles.