Development And Application Of High Power IGBT Module Dynamic Switching Performance Test Platform

The high power insulated gate bipolar transistor(IGBT)module is widely used in high power converter systems,such as wind power generation systems and Voltage Source Converter based High Voltage Direct Current Transmission(VSC-HVDC)systems.Its reliability is the key to ensure that high power converter systems can work for a long time.However,the study on high power IGBT is based on off-line testing.The online characristics of IGBT are barely available.Therefore,the high power IGBT switching characristic on-line test platform should be built.The platform can be used to choose suitable IGBT modules and find some weakness of the new converter systems.In this way,the reliability of the real power conversion systems can be improved a lot.Firstly,a MW-level practical operation reappearance test bench with H-bridge topology is constructed,which can simulate different work conditions in the real power conversion systems.IGBT switching characristics can be got while the platform is working.The problem of using IGBT properly in real power conversion systems can be solved.Then,a method of compensation the dead-time is used so that the ripple current in H-bridge can be the same as in the real power conversion systems.Junction temperature monitoring for High power IGBT modules is of great importance for reliability issues in the voltage-source-converters.How to achieve online dynamical junction temperature extraction is significantly challengeable in the power electronics community.In this papaer,the turn-off delay time is employed as a thermal sensitive electrical parameter for the dynamical junction temperature extraction.And the relationship among the turn-off delay time,junction temperature of IGBT module and collector current is established.The 3-D database is built by the experimental results from the operation reappearance test bench.Furthermore,as one of the most important factors that affect the junction temperature,the IGBT power loss is analyzed.And the IGBT junction temperature variation with load frequency change is also studied to show that the turn-off delay time is an excellent candidate for online dynamical junction temperature extraction due to its high sensitivity,fast response and easy integration.