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关键词： Insulated gate bipolar transistors   Thermal degradation   Finite element analysis   Thermal resistance   Solid modeling   Degradation   Thermal analysis   Base solder   degradation   finite-element method (FEM)   insulated-gate bipolar transistor (IGBT)   thermal network model  

摘要： With the development of power electronic technology, the thermal characteristics of high-power insulated-gate bipolar transistor (IGBT) module are vital information for thermal management of power electronic equipment, reliability analysis, and thermal design of power electronic system. However, the present commonly used lumped thermal network model based on thermal resistance and heat capacity still has some limitations in accurately predicting the junction temperature of IGBT modules, significantly once considering the degradation of base solder in high-power IGBT modules. In this article, the thermal behavior of high-power IGBT chips under different base solder degradation is studied by the finite-element method (FEM). The results show that the degradation of the base solder has effects on the thermal impedance between the junction and the case, which should be fastidiously thought about within the thermal network model modeling. As a result, a dynamic 3-D thermal network model that considers the thermal interaction between IGBT chips, as well as the degradation of the base solder, is proposed in this article. The proposed thermal network model can estimate the junction temperature of a high-power IGBT module correctly and fast based on the real degradation of the base solder. Finally, finite-element simulation and experimental findings are used to validate the proposed dynamic 3-D thermal network model. The results show that the dynamic 3-D thermal network model has comparable accuracy to finite-element simulation and test results. At the same time, the dynamic 3-D thermal network model responds faster than the finite-element simulation.

关键词： Collector current rising rate   collector-emitter voltage falling rate   field-stop (FS) insulated gate bipolar transistor (IGBT)   IGBT modeling   turn-ON  

摘要： In this article, a complete expression for dV(CE)/dt and dI(C)/dt at turn-on transient of field-stop (FS) insulated gate bipolar transistor (IGBT) is proposed. With numerical simulation utilized, the critical stray elements and internal physics which have a significant impact on turn-on behavior of FS IGBT are identified. Based on the improved understanding on the turn-on behavior, the turn-on transient is divided into two phases and the equivalent circuits of each phase are obtained. The analytical expressions of dV(CE)/dt and dI(C)/dt during the turn-on transient are thereby derived based on the equivalent circuits. The temperature dependency on the turn-on characteristics of FS IGBT is identified by the experimental data. The temperature-dependent models of various device parameters are proposed to describe the temperature dependency. In the end, the double-pulse test is performed on a 650-V FS IGBT and a 1200-V FS IGBT. The good agreement between the test and analytically derived results validates that the proposed FS IGBT model can accurately predict the dV(CE)/dt and dI(C)/dt during the turn-on transient.

关键词： Insulated gate bipolar transistor (IGBT) module   iterative Clech algorithm   physical lifetime prediction method   successive initiation (SI) method   viscoplastic strain energy density (VSED)  

摘要： Thermal-mechanical coupled models built by finite-element analysis (FEA) software are attractive due to its excellent capability to calculate thermal/mechanical behaviors of the material interfaces inside the power module. However, these FEA-based approaches will consume enormous computational resources, resulting in unacceptably long simulation times. Here, a computationally efficient and accurate insulated gate bipolar transistor (IGBT) lifetime prediction method enabling explicit emulation of solder layer degradation is proposed with the assistance of Clech algorithm. The variation of assembly stiffness $K$ and imposed strain $D$ in the Clech algorithm with the geometrical variation during the solder layer degradation is particularly considered. A lookup table of $K$ and $D$ changing with crack propagation is established to calculate viscoplastic strain energy density $\Delta W$ (VSED) of the critical elements across the crack path. This improved process is applied for lifetime consumption calculation of each successive run. It remarkably reduces the simulation costs compared to that based on FEA. Finally, two sets of experimental results verify high prediction accuracy and low time-consuming cost of the proposed method.

关键词： Insulated gate bipolar transistors (IGBT)  

摘要： Now occupying a 1,000sq mtr site, with the capability of even further expansion, the company is riding high thanks to its refinement of IGBT inverter technology and ability to offer a wide range of induction melting furnace bodies including tilting, rollover and crucible drop coil styles, plus a vast range of spare parts and service for various brands of furnace and melting equipment.

关键词： Insulated gate bipolar transistors   Logic gates   Wires   Germanium   Monitoring   Fatigue   Temperature measurement   Diagnosis   IGBT chip failure   multichip insulated gate bipolar transistor (IGBT) module   online monitoring  

摘要： To achieve the desired current capability, insulated gate bipolar transistor (IGBT) modules are normally composed of parallel chips. The bond wires fatigue on a certain chip will gradually cause the performance of the power module to degrade, and eventually lead to an unexpected catastrophic failure of the entire system. Therefore, this article proposes an in situ diagnosis method for bond wires fatigue in multichip IGBT modules based on a newly defined characteristic parameter. By sensitivity analysis, horizontal comparison, and experimental test, the parameter was proven to have the advantages of being safe, low-sensitive to operation conditions, and easy to extract. Correspondingly, the online monitoring circuit was designed on the basis of the voltage clamping technology, and further applied on an inverter prototype with 100 A peak current and 10 kHz switching frequency. The results showed that although with large change of junction temperature and load current, the proposed method can accurately diagnose IGBT chip failure by the sudden increase in the amplitude of the parameter. Moreover, the monitoring circuit can be both plug-and-play in the existing inverters and integrated in the gate drive circuit owing to the compact design, which is expected to avoid catastrophic failures of the inverter in field application.

关键词： Current overshoot   gate voltage active control   insulated gate bipolar transistor (IGBT)   multi-level synthesis   sensitive parameters  

摘要： Compared with the conducting and blocking steady-state processes, the voltage and current stress of insulated gate bipolar transistor (IGBT) become very higher in the turning-on and turning-off transient processes, and the instantaneous power loss increases significantly. The switching transient conditions greatly affect the reliability and stability of IGBT devices and power converters. During the IGBT turning-on process, the reverse recovery of the symmetrical bridge arm anti-paralleled diode can cause additional turn-on loss and current peak overshoot. The gate voltage active control technology can effectively suppress current spike and reduce turn-on loss in the period from the initial opening time to Miller platform. The multi-level synthesis technology can adjust the gate voltage waveform and produce depression or bulge in the normal driving voltage waveform for a certain time. In this article, the sensitive parameters of gate voltage active control, which affect the current overshoot, and turn-on loss of IGBT are studied based on the theoretical calculation and mathematical model. A multi-level synthesis gate voltage active control technology is proposed according to the principle of gate voltage active control. The relationship among the acting voltage amplitude, execution time, current peak, and switching loss is studied. Considering the actual application conditions, the optimized active control scheme of gate voltage is designed. Finally, the switching characteristics test is carried out, the results verify that the proposed control technology can effectively reduce the current overshoot and turn-on loss in comparison with the conventional schemes.

关键词： Insulated-gate bipolar transistor (IGBT) power modules   optimal design   reliability analysis   vapor chamber  

摘要： As an important device for energy conversion, insulated-gate bipolar transistor (IGBT) modules are widely used in various applications. Generally, IGBT power modules work in a harsh environment, and their reliable operation is of high importance. However, most of the existing package design methods fail to provide sufficient reliability for IGBT modules. To address this, an optimal package design method for IGBT modules is proposed in this article. In the proposed design method, the vapor chamber is embedded in the copper substrate. Based on this, a satisfactory performance of spreading heat is accordingly achieved. Moreover, a thermal stress analysis of the IGBT power module with the proposed design method is then provided. The analysis under the high load working state reveals the proposed design method can reduce the chip junction temperature by 12 ?. The optimized structure brings lower thermal stress and a more uniform temperature and consequently maintains the reliability of the IGBT power modules. Experimental tests have verified the performance of the proposed optimization design method.

关键词： Phase field method   IGBT   Fatigue crack propagation   Anand constitutive model  

摘要： Insulated Gate Bipolar Transistor (IGBT) is a key device in power system. During its service, due to the mismatch of thermal expansion coefficients, cracking of the solder layer may result in reliability concerns. However, the thickness of the solder layer is generally only tens of microns, so it is challenging to study the dynamic crack propagation in the solder layer. In this study, the viscoplastic phase field method is combined with the Anand viscoplastic model commonly used in solder alloys to simulate the dynamic fracture of the IGBT solder layer during temperature shock test (TST). The simulation results are compared with the experimental results and the results are very close. In this paper, the effect of solder voids and solder inclination on crack propagation is studied by using phase field method. It is found that the presence of voids promotes crack propagation, and the crack propagation rate is faster on the thin side when the solder is tilted.

关键词： 收敛速度   平均场线性二次最优控制问题   闭环控制策略   Riccati 方程  

摘要： 本文就平均场系统的线性二次最优控制(linear quadratic optimal control, LQ)问题提出基于反馈控制的数值算法.首先,将原问题分解为两个子问题:随机系统的LQ问题和确定系统的LQ问题.其次,依次对两个子问题利用反馈控制策略进行离散化,并证明该离散的收敛速度.最后,给出数值例子来支撑理论结果.