| With the continuous development of science and technology and the increase of power consumption in cities,people's demand for the capacity of power semiconductor voltage and current is increasing day by day.Insulated gate bipolar transistor(IGBT)has the advantages of low parasitic inductance,large power capacity,fast switching speed,short circuit failure,so it is widely used in high-voltage and high-power transmission and distribution engineering.In order to ensure the reliability of devices under working conditions,IGBT devices need to carry out high temperature reverse bias(HTRB)test before leaving the factory.The device under test(DUT)needs to be tested at the specified temperature to obtain accurate test results,so the junction temperature of the device needs to be monitored in real time during the trial.For IGBT devices,the thermal resistance changes with the temperature and the pressure exerted by the fixture,so it is very difficult to test the thermal resistance.Therefore,it is particularly difficult to calculate the junction temperature via thermal resistance.In order to monitor the junction temperature of the DUT in real time during the HTRB test,the junction temperature of the DUT was monitored by the electrical method.The leakage current was selected as the temperature sensitive parameter in the experiment,and the one to one correspondence relationship between the leakage current and the junction temperature under standard voltage was used to calculate the junction temperature of the DUT.In addition,in order to solve the problem that press pack IGBT is double-side heat dissipation so it is difficult thermal resistance measurement of pressed IGBT devices.this paper use water cooling radiator inlet and outlet water temperature to test the heat dissipation power ratio,so as to calculate the double-side thermal resistance of the device.Besides,the thermal resistance test fixture was designed and manufactured to meet the thermal resistance test needs of devices.Specific contents include the following:1.The principle of leakage current temperature measurement method is studied,and the testing platform of leakage current temperature calibration curve is built.The influence of voltage fluctuation on test results is discussed,and the e index formula is used to fit the calibration curve2.In order to avoid the influence of self-heating generated in the measurement process of the relationship between the blocking leakage current and temperature on the calibration curve,the relationship between the heat generated by the power pulse and the temperature rise of the chip at different temperatures is studied.3.The leakage current temperature measurement method is used to measure the temperature of the device under test in the 8-hour high temperature reverse bias test,and the test results were compared with the traditional method for calculating junction temperature by thermal resistance,which verified the accuracy of the leakage current temperature measurement method.4.In order to study the influence of pressure on the temperature and thermal resistance measurement of press pack IGBT,a test fixture for press pack IGBT with single chip is built.The fixture can exert measurable and adjustable pressure on devices,provide electrical connection for devices,and exert uneven pressure on devices.The variation of the electrical characteristics of press pack IGBT with temperature and pressure was studied.5.The influence of thermal convection and radiation on the double-sided thermal resistance test results was studied,and a 3300V/1500 A press pack IGBT double-sided thermal resistance test platform is built.The heat dissipation ratio of surface C and surface E of the device was calculated,and the double-sided thermal resistance of the device was calculated. |
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