Research Of Insulated Gate Bipolar Transistor Junction Temperature Simulation Model And Its Application

In recent years, with the improvement of semiconductor manufacturing process andthe application requirements of power electronics system, the power grade and densityof IGBT module in the power converter system become higher and higher, which forcesits internal power devices to bear very high heat stress, especially in the application ofwind power converter systems whose working environment is bad and output powerfluctuate dramatically. As a result, the lifetime and long-term reliability of IGBT moduleare affected notably. The junction temperature is not only directly related to IGBTmodule’s lifetime and reliability, but also affects its performance capability; it may evenchange the harmonic distribution of convert’s output waveform. Therefore, to get theconverter’s junction temperature in IGBT module has prominent meaning to assure itsreliability and the reasonable choice of cooling devices. This paper will do the researchwork on the method of simulating the prediction of IGBT module’s junctiontemperature、the influencing factor of junction temperature in three-phase invertersystem and the junction fluctuation under unstable working condition in wind powerinverter system.All the power electronics devices in operation will lose some energy and IGBT do,too. Usually, this part of loss energy exists in the inner part of IGBT in the form of heat,which will change the temperature distribution of power electronics devices. In thispaper, we firstly analyze the package structure of IGBT、the heat transfer process in themodule and summarize the definition of module thermal resistance. On this basis wemake the theoretical modeling for the one-dimensional heat transfer which dominates inthe IGBT module. Then the calculation method of working junction temperature isdeduced. According to the knowledge of semiconductor physics theory, the temperatureeffect of silicon chips is summarized. On this basis, the temperature effect of IGBT isanalyzed from the point of view of experiment and theory. Also this elaborate that thechange of IGBT’s junction temperature is the comprehensive effect of heat andelectricity.The mathematical physics model of IGBT devices are studied using a modelparameters extraction method which combines parameters isolation experiment and theempirical equation, and the burst signal junction characteristics of specific types IGBTdevices are simulated in saber software using the parameters extracted from them. Thus the dynamic changes process of the devices’ work junction temperature is analyzedfrom the view of power semiconductor devices’ physics model.Aiming at the problem that the simulation step is too short、consuming too much timeand difficult to converge in simulating the junction temperature with the IGBT devices’mathematical physics model. This paper build the system level IGBT module’s junctiontemperature simulation model with the method which combines the loss model and heattransfer network model. The two models are based on mathematical operation method.Using this method, the simulation speed of junction is improved. Because the modeltakes account of the thermoelectric coupling effect, the IGBT module’s junction changeprocess under actual working conditions can be simulated more precisely.Based on the fact that the peak junction temperature and steady-state fluctuation isthe direct factor which affect the reliability and lifetime of IGBT module in its workingprocess, the influence of different load conditions and working environments to thepeak junction temperature and steady-state fluctuation are discussed through thesimulation model of three-phase inverter system’s IGBT module in this paper. TheIGBT module’s junction temperature fluctuation in a period of time is simulated for thespecified application of frequency converter in wind power system, which providessome theory basis for the on-line monitoring and control of IGBT module’s junctiontemperature.