Research On Heat Dissipation Characteristics Of IGBT Module Package

IGBT has many excellent characteristics including fast switching speed, high inputresistance, low saturation voltage, low on-state voltage drop, shot reverse recovery time andso on. Presently, power electronic device IGBT package module plays an important role innational economy, especially in wind energy, solar energy, rail transit, electro mobile, smartGrid, inverter. IGBT package module has become the hot spot in global academic field. As thedemand for IGBT increase, many aspects of IGBT module including performance,manufacture, power density, reliability have stepped into a new stage. The failure of IGBT,however, is becoming worse with the increase of power density. Thus, it is of crucialimportance that studying on heat transfer characteristics of IGBT package module anddesigning simple and efficient heat dissipation device.This paper introduce the fundamental principle of heat transfer, heat transfer methodinvolved in high power device module, the reason of device failure, the heat dissipationmethod and developing situation. Based on the traditional IGBT module and finite elementanalysis, the IGBT model is established by ANSYS and the effect of internal structure to heatdissipation is discussed. It is found that the IGBT chips have a excellent heat dissipatingperformance when the chips take full advantage of the Cu base-plate horizontally,high-thermal-conductivity material in ceramic layer is also good for heat dissipation, thehorizontal area of DCB substrate has little effects on heat dissipation and junction temperaturedeclines dramatically in small scale and then ascends slowly with the increase of Cubase-plate thickness. There exists an “optimum thickness” for the Cu base-plate which makesthe junction temperature becomes the lowest. Although the thermal resistance of the substratestays the same, junction temperature decrease and the “optimum thickness” become smaller asthe DBC substrate goes thicker.The actual test and theoretical calculation are conducted to validate the rationality ofestablished model based on ANSYS. The IGBT model which is based on unfolding a realcommercial IGBT module is established and simulated result of junction temperature and Cubase-plate is72.2℃and51℃respectively. Another same IGBT module is used for actualtest, the measured Cu base-plate temperature turns out to be49.6and the junction temperatureis70℃after the relationship between on-state collector-emitter voltage and junctiontemperature should is confirmed. Based on heat-circuit analogy, the junction temperature iscalculated to be73.4℃. In all, error rate of simulated result and the theoretical calculationresult is3.14%and4.8%respectively if actual test result is set as reference. Thus, simulatedresult and theoretical result are convincible to some extent, which is important to IGBTmodule manufacture.