Reliability Evaluation Method Of High-voltage And High-power IGBT Module Based On Temperature-sensitive Electrical Parameters

Insulated Gate Bipolar Transistor（IGBT）is the core component of power converters and the component with the highest failure rate.Its reliability is an important issue in the field of power electronics.The main reason for the failure of the IGBT module is the fatigue of the solder layer or the peeling off of the bonding wire.In order to improve the service life of power converters,IGBT module reliability research has become a research hotspot at home and abroad.This article has carried out relevant research on the reliability evaluation method of high-voltage and high-power IGBT module based on temperature-sensitive electrical parameters.The main contents include:First,this article introduced the packaging structure,heat transfer method and failure mechanism of the IGBT module.According to the structural characteristics of the multi-chip parallel IGBT module,its aging failure characteristics were analyzed,and the dynamic characteristics of the gate,the voltage V_{GE（pre-on）}before the gate-emitter turn-on,and the module transconductance g_m were selected for the reliability evaluation of the IGBT module.Secondly,we established the gate-emitter equivalent RLC circuit.According to the relationship between the IGBT gate voltage V_GE and the gate current i _G and the internal intrinsic parasitic element RLC,a reliability model of the gate dynamic characteristics was established.The pre-on voltage V_{GE（pre-on）}in the gate voltage V_GE trace was selected as the TSEP of the IGBT chip failure,and the gate-emitter voltage reliability model before the turn-on was established.The module transconductance was defined according to the transmission characteristic curve of the IGBT module,the relationship between the module transconductance and the equivalent resistance of the IGBT module bonding wire and junction temperature fluctuation was analyzed in detail,and the module transconductance reliability model was established.Next,according to the above-mentioned IGBT module reliability model,the DIM800NSM33-F IGBT module was tested for different numbers of IGBT chip failure tests and bonding wire failure tests in the test circuit,and the gate current i _G and the gate were measured on the low-voltage gate side.Emitter voltage u _GE and collector current i _C.In the reliability model based on the dynamic characteristics of the grid,the grid current and voltage waveforms were different in different health states.In the reliability model based on the gate-emitter voltage before the turn-on,V_{GE（pre-on）}was measured with a fixed delay time.The small changes in the external gate resistance R_G（ext）and the gate driver power supply voltage V_GG were tested to verify the V_{GE（pre-on）}anti-interference performance.In the reliability model based on the module transconductance,the module transconductance value was calculated according to the transmission characteristic curve obtained from the test.In order to avoid the temperature dependence of the module transconductance concealing its fault characteristics or reducing its accuracy,the module transconductance g_m was temperature-corrected to eliminate the influence of temperature.The temperature-corrected module transconductance can effectively monitor chip faults and bond wire faults in IGBT modules.Finally,we proposed a comprehensive evaluation method for the reliability of IGBT modules.The correlation coefficient was used to characterize the health of the IGBT module,and the gate current,gate voltage and transmission characteristic curve were selected as the characteristic vector,and theρunder different fault states was calculated to obtain the health of the IGBT module.Define the comprehensive module reliability indexα,set the threshold valueα_set,and evaluate the reliability of the IGBT module according to the module reliability comprehensive indexα,so that new IGBT modules can be replaced in time to ensure the safe operation of the entire power electronic device and system.