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关键词： IGBT module   Solder layer   High temperature gradient   Fatigue mechanism   Inelastic strain energy density   Lifetime prediction  

摘要： With the increase in the power density of power semiconductor chips, the lateral temperature gradient over the chip surface becomes more pronounced. Temperature gradients play an important role in reliability evaluation of IGBTs and have attracted great attentions. In this paper, the influence of IGBT chip temperature gradients on the crack initiation site and propagation path of the solder layer is investigated by finite-element analysis (FEA). Results indicated that the temperature gradient could influence the mechanism of solder layer fatigue. With the temperature gradient increasing, the crack initiation site shifts from the edge of solder layer to the center. The crack propagation path also changed. The fatigue mechanism of the solder layer under high temperature gra-dients is investigated by FEA. The inelastic strain energy density per cycle (Delta W) is found to be unequal at crack initiation and crack propagation stages. Accordingly, a novel energy-based lifetime prediction model based on Darveaux's model for solder layer fatigue of IGBTs is proposed, which takes into account the variation of Delta W within these two stages and can better characterize the processes of crack initiation and propagation in the solder layer. Subsequently, two lifetimes of IGBT modules under accelerated aging tests from the existing publications are used to verify the effectiveness of the proposed model. Finally, the accelerated aging tests were carried out to support the theoretical analysis on the direction of crack propagation under high temperature gradients.

关键词： power semiconductor   insulated gate bipolar transistor (IGBT)   super-junction IGBT (SJBT)   trade-off   turn-off loss (E-off)   on-state voltage (V-on)   breakdown voltage (BV)   machine learning (ML)   neural network (NN)   optimization   reverse engineering  

摘要： An improved structure for an Insulated Gate Bipolar Transistor (IGBT) with a separated buffer layer is presented in order to improve the trade-off between the turn-off loss (E-off) and on-state voltage (V-on). However, it is difficult to set efficient parameters due to the increase in the new buffer doping concentration variable. Therefore, a machine learning (ML) algorithm is proposed as a solution. Compared to the conventional Technology Computer-Aided Design (TCAD) simulation tool, it is demonstrated that incorporating the ML algorithm into the device analysis could make it possible to achieve high accuracy and significantly shorten the simulation time. Specifically, utilizing the ML algorithm could achieve coefficients of determination (R-2) of V-on and E-off of 0.995 and 0.968, respectively. In addition, it enables the optimized design to fit the target characteristics. In this study, the structure proposed for the trade-off improvement was targeted to obtain the minimum E-off at the same V-on, especially by adjusting the concentration of the separated buffer. We could improve E-off by 36.2% by optimizing the structure, which was expected to be improved by 24.7% using the ML approach. In another way, it is possible to inversely design four types of structures with characteristics close to the target characteristics (E-off = 1.64 mu J, V-on = 1.38 V). The proposed method of incorporating machine learning into device analysis is expected to be very strategic, especially for power electronics analysis (where the transistor size is comparatively large and requires significant computation). In summary, we improved the trade-off using a separated buffer, and ML enabled optimization and a more precise design, as well as reverse engineering.

关键词： Reliability   Semiconductor device modelling, equivalent circuits, design and testing   semiconductor device models   bonding wire failure monitoring   device electro-thermal coupling   Power semiconductor devices   semiconductor device reliability   insulated gate bipolar transistors   failure analysis   failure conditions   power semiconductor devices   insulated gate bipolar transistor modules   Bipolar transistors   fatigue   Insulated gate field effect transistors   important failure modes   Finite element analysis   Numerical analysis   IGBT module   finite element analysis   IGBT lifetime evaluation  

摘要： Insulated gate bipolar transistor (IGBT) modules are widely used as power switching devices. In actual working conditions, the failure of bonding wires is one of the most important failure modes. At present, the influence of bonding wire failure is not considered in the reliability evaluation of the device, resulting in a large error in the life prediction result. Therefore, this paper proposes a life evaluation method for IGBT modules that takes into account the failure of the bonding wire. The transient thermal impedance of 1200 V/50 A IGBT module under the failure conditions of different numbers of bonding wires is calculated by constructing a finite element simulation model of device electro-thermal coupling. Both simulation and experimental results show that with the increase of the number of bonding wire failures, the transient thermal impedance curve of the device rises and the steady-state thermal impedance increases. The Foster thermal network models of the devices are updated, and the number of power cycles of the device with bonding wire failure under DC and sinusoidal pulse width modulation (SPWM) conditions is calculated. When the number of bonding wire failures and fatigue accumulation have a linear relationship, the life will be reduced by 48.29% compared to the healthy state.

关键词： Circuit faults   Voltage measurement   Fault diagnosis   Sensors   Insulated gate bipolar transistors   Capacitors   Kalman filters   Amending Kalman filter (KF)   capacitor voltage   modular multilevel converter (MMC)   open-circuit fault diagnosis  

摘要： The insulated-gate bipolar transistor (IGBT) is one of the most vulnerable components in the modular multilevel converter (MMC). One or more IGBT open-circuit faults may deteriorate the output performance of the MMC and even destroy the MMC systems. In this article, a concurrent and direct fault diagnosis method has been proposed. The capacitor voltages are estimated with an amending Kalman filter (KF). By comparing the measured and estimated values, the corresponding faulty submodule (SM) can be detected directly and quickly. The diagnosis process of SMs is independent of each other so that all the SMs can be monitored in real time and the diagnosis time will not increase with multiple open-circuit faults occurring. The proposed method can also identify which IGBT has occurred open-circuit fault in the faulty SM and has no special requirement for the modulation method. In addition, the amending KF has excellent robustness to the transient process and can overcome the divergence problem, which is applicable in the complex nonlinear MMC system. The effectiveness of the proposed fault diagnosis method is confirmed by simulation in MATLAB/Simulink and experimentation in a single-phase MMC prototype with eight SMs per arm.

关键词： IGBT open-circuit fault   data augmentation   generation model   auto-encoder   few-shot learning  

摘要： With the rapid development of converters in a variety of industrial fields, the fault diagnosis of power switching devices has become an important factor in ensuring the safe and reliable operation of related systems. In recent years, machine learning has performed well in many fault diagnosis tasks. The success of these advanced methods depends on sufficient marked samples for each fault type. However, in most industrial applications, it is expensive and difficult to collect fault samples, and the fault diagnosis model trained under the limited samples cannot meet the requirements of fault diagnosis accuracy. In order to solve this problem, this study proposes a few-shot learning method based on fault sample generation to realize the open-circuit fault diagnosis of IGBT in a three-phase PWM converter. This method is the deformation of the auto-encoder called the disturbance auto-encoder generation model. By designing the model structure and training algorithm constraints, the encoder learns the nonlinear transferable disturbance from the normal operating sample pairs. Then, the disturbance is applied to the decoder to synthesize new fault samples to realize the training of the fault diagnosis model with limited samples. The biggest advantage of this method is that it can achieve 95.90% fault diagnosis accuracy by only collecting the samples in the normal operating conditions of the target system. Finally, the feasibility and advantages of the proposed method are verified by comparative experiments.

关键词： 双三相永磁同步电机   直接转矩控制   单相开路故障   虚拟矢量修正  

摘要： 正常双三相电机直接转矩控制运行需要对基本电压矢量进行修正,采用修正后的虚拟矢量进行直接转矩控制可以抑制谐波电流。双三相电机缺一相故障直接转矩控制时,需要对电压矢量重新进行修正。该文给出了双三相电机缺一相故障情况下的电压矢量分布,提出一种双三相电机缺一相运行时虚拟矢量的间接修正方法,并且使虚拟矢量的幅值达到最大。构建双三相电机缺一相容错直接转矩控制策略,其定子磁链分区和开关表的选取规则与双三相电机正常运行时一致,其差别只是缺一相运行时十二个虚拟矢量的幅值有所减少,因此比较易于实现。实验结果验证了所提方法的正确性和可行性。

关键词： 清灰装置   变频器   维护管理  

摘要： 为确保网络信息系统安全、平稳运行,精密仪器设备、机房等场所都需使用合理、高效的除尘装置进行定期的维护清洁。本文就灰尘对人体、设备设施的影响及精密仪器、机房场所室内灰尘的来源进行分析,并说明如何通过运用变频器控制双风机除尘设备进行清灰,并取得良好效果。

关键词： 无极绳绞车   辅助运输   变频控制   变频器  

摘要： 介绍了无极绳绞车变频控制系统结构组成、功能,并以矿井井下实际情况为依据对变频控制系统改造方案进行设计。现场应用表明,无极绳绞车采用变频控制系统后,可实现绞车的启停、正反转、安全保护等功能,绞车运行可靠性及效率得以提升,同时绞车运行速度可根据运输巷道底板起伏变化情况进行调整,可在一定程度上提高绞车运行安全性。

关键词： 模块化多电平换流器   功率循环   压接型IGBT   门极驱动信号   门极氧化层裂纹  

摘要： 压接型高压IGBT是柔性直流输电用模块化多电平换流器(modular multilevel converter,MMC)中的核心器件,其在长期运行中逐渐发生热老化并最终失效,影响着MMC的运行性能。利用压接型高压IGBT的门极驱动信号演化规律监测器件状态对于是实现MMC子模块状态监测的重要手段。文中首先搭建了压接型IGBT功率循环试验平台,并在功率循环试验过程中定期测试器件门极驱动信号波形。结果表明随着老化循环次数的增加,压接型IGBT门极驱动电压上升沿米勒平台时间长度增大,门极驱动电流下降沿凹槽位置滞后。其次,对热老化失效以后的压接型IGBT芯片表面进行观测,发现芯片发射极门极氧化层附件出现裂纹,这一热老化失效形式是门极驱动信号变化的主要原因。最后,根据压接型IGBT内部多物理场耦合关系建立了有限元仿真模型,计算结果表明热应力在附加金属层与下钼层接触界面的边缘区域数值较大,在长期交变的应力疲劳后造成门极氧化层裂纹萌发,逐渐导致门极失效。文中研究结果说明了利用压接型高压IGBT门极驱动信号演化规律在线监测其门极老化状态具有一定意义。