Research On IGBT Double-sided Thermal Resistance And Junction Temperature Measurement Method In Blocking State

Insulated Gate Bipolar Transistor(IGBT),as a core device in the field of power electronics,is widely used in various flexible DC transmission projects.Because IGBTs need to work for a long time under high-frequency,high-voltage,and high-current working conditions,and are not easy to replace in application fields such as power transmission grids and aerospace,high requirements are placed on the reliability of their devices.The junction temperature of the chip and the thermal resistance of the junctionto-case,as two key factors affecting device reliability,are important indicators for measuring product reliability.Therefore,this article is divided into three parts for research on the junction temperature of the internal chip of the IGBT module and the measurement of the junction-to-case thermal resistance:1.First,the relationship between the leakage current of the IGBT chip and the junction temperature is deduced,and the law of the leakage current of the chip with the temperature in the blocking state of the device is proposed to establish a temperature calibration curve to determine the junction temperature of the chip under the normal working state of the IGBT module.Conduct on-line measurement,and use the low current temperature measurement method and traditional thermal resistance calculation method to compare the temperature measurement results of the leakage current temperature measurement method by building a switch experimental circuit,verify the temperature measurement accuracy of the method,and apply the method In the high temperature reverse bias test(High Temprature Reverse Bias,HTRB),one of the IGBT module factory reliability assessment tests,the online junction temperature measurement of the IGBT chip in the HTRB test state is performed,thereby solving the problem of blocking state power in the HTRB test.It is difficult to measure the junction temperature of the chip inside the module due to the self-heating caused by the power consumption.2.The internal heat conduction mechanism of the crimping type IGBT is studied.Aiming at the problem of measuring the thermal resistance of the double-sided junction of the crimping type IGBT module,it starts from the three aspects of theory,simulation and experiment.First,in theory,the total power consumption of the module is divided into two parts: collector and emitter,and the relationship between the heat dissipation ratio of the two poles of the chip,power consumption and heat flux is calculated,and the dual power consumption of the module is finally obtained by the ratio of the power consumption of the two poles.Surface thermal resistance.In terms of simulation,a single-chip simulation model was established for the flexible crimping IGBT module(model: 5SNA 3000K452300)produced by ABB Company from the structural point of view,and the finite element simulation analysis software ANSYS was used to conduct a temperature-structure multi-physics coupling simulation inside the module.Calculate the heat flux on both sides of the chip's collector and emitter,and get the ratio of the heat flux of the two poles of the chip—qc: qe=82%:18%,and the thermal resistance of the junction and shell of the two poles—Rjc-c=0.0298(K/W);Rjc-e=0.308(K/W).3.In terms of experiments,the on-line test method for the thermal resistance of the double-sided junction of the crimping type IGBT module is studied,and it is proposed to indirectly measure the power consumption of the two poles of the chip by measuring the water temperature of the upper and lower poles of the water-cooled radiator in the working state of the module.This test theory builds a supporting doublesided thermal resistance test platform,and tests the sub-module of the flexible crimping IGBT module(model: 5SNA 3000K452300).The actual measurement of the submodule's double-sided junction thermal resistance: Rjc-c=0.0313(K/W);Rjce=0.253(K/W),which is very close to the value obtained by simulation.Finally,the total thermal resistance of the sub-module is calculated by the parallel calculation formula Rjc=0.028(K/ W)is closer to the product data sheet value Rjc(datasheet)=0.0192(K/W),which verifies the correctness of the theoretical derivation and the accuracy of the simulation results.