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关键词： Switches   Voltage control   Control systems   Limiting   Insulated gate bipolar transistors   Thyristors   Arresters   Power systems   Energy consumption   Threshold voltage   Bypass switch   controllable arrester   IGBT   voltage suppression and energy consumption  

摘要： As the power system develops toward larger capacity and greater integration of new energy sources, the proportion of sensitive equipment such as power electronic converters is increasing, resulting in a heightened need for overvoltage suppression. The controllable arrester (CA), as a novel device capable of achieving deep overvoltage suppression, has gained significant attention. However, the use of semicontrolled switches in CAs often results in difficulties with exiting after activation in dc systems, leading to excessive energy absorption and limited suppression capability. This article proposes a novel controllable arrester with flexible operation (Flexible CA) for dc transmission systems. By integrating a fully-controlled switch with the existing semicontrolled switch, the Flexible CA enables both rapid operation and flexible exit capabilities, while also decoupling overvoltage suppression from energy absorption. Detailed parameter configuration and working strategies allow for improved performance in overvoltage suppression and energy management. Finally, 2 kV and 25 kV prototypes of Flexible CA and overvoltage suppression experimental platforms have been developed to validate the feasibility of the proposed design. In addition, a +/- 500 kV/3000 MW offshore VSC-HVdc simulation system with the Flexible CA has been also established. The results demonstrated effective decoupling of overvoltage suppression from energy consumption, limiting overvoltage to 1.6 p.u. while reducing excess energy demand by at least 54.1%, with better techno-economic performance.

关键词： Fault diagnosis   fault location   neural networks   three-phase dc-ac inverters   fault location   neural networks   three-phase dc-ac inverters  

摘要： This article presents a novel fault diagnosis method for open-circuit faults of insulated gate bipolar transistors (IGBTs) and current sensor faults in three-phase sinusoidal pulsewidth modulation inverters. The proposed method facilitates the simultaneous diagnosis of multiple IGBT and current sensor faults. A combination of Park transform and fast Fourier transform (FFT) is employed to extract fault features. The Park transform converts three-phase current into two-phase current, thereby reducing the dimensionality of the data. The FFT integrates time-domain and frequency-domain analyses to enhance the representation of fault characteristics. Additionally, fault features are extracted from the samples post-FFT to minimize the data volume of individual sample input by the model. For fault diagnosis, a temporal convolutional neural network model incorporating stacked residual blocks is developed to train and evaluate potential faults and demonstrate the model's validity and accuracy. The results of online simulations and hardware-in-the-loop experiments indicate that the proposed method can identify and locate the IGBT and sensor faults within 32 ms, and the accuracy is 98.75%. This method achieves higher training and testing accuracy and faster training and testing speed, which is superior to the existing diagnosis technologies.

关键词： Finite element analysis   Insulated gate bipolar transistors   Predictive models   Market research   Temperature measurement   Computational modeling   Temperature distribution   Thermal resistance   Semiconductor device measurement   Mathematical models   Dynamic mode decomposition (DMD)   finite element method (FEM)   insulate-gate bipolar transistor (IGBT)   temperature field prediction  

摘要： The detailed temperature field distribution of high-power insulated gate bipolar transistor (IGBT) modules is important information for the reliability analysis and thermal design of power electronic systems and it is difficult to obtain quickly. This article proposes a hybrid model for temperature field prediction based on dynamic mode decomposition (DMD) and deep learning for IGBT modules. First, the IGBT temperature field (ITF) snapshot is obtained through finite element simulation. Second, the DMD is used to extract stable and unstable trends of the ITF snapshot, and the future stable trend is predicted by recursion. Third, a deep learning model autoencoder-long short-term memory is proposed to predict the future unstable trend. Finally, the ITF prediction snapshots are obtained by adding the future stable and unstable trends. The proposed hybrid model prediction method realizes precise ITF prediction and significantly reduces the computation time. Experimental and simulation results validate the viability of the proposed method.

关键词： Insulated gate bipolar transistors   Stress   Junctions   Failure analysis   Employee welfare   Copper   Temperature distribution   Analytical models   Strain   Molybdenum   Failure weak point   long-term aging failure mechanism   modular multilevel converter (MMC) working condition   press-pack insulated gate bipolar transistor (PP IGBT)  

摘要： Converter valves based on the modular multilevel converter (MMC) topology are the core of the voltage source converter-based high-voltage direct current transmission system, with press-pack insulated gate bipolar transistor (PP IGBT) modules being the key components. Studying the long-term aging failure mechanism of the PP IGBT under actual MMC operating conditions is of great significance for improving the safe and reliable operation of the transmission system. In this article, an electric-thermal-mechanical coupled multifield model of the PP IGBT device is built to analyze the influence of junction temperature and pressure on stress and strain distribution, identifying the weak points. Then, based on the alternating current (ac) power cycling tested rig, which equivalently reproduces the working conditions of the MMC submodule, the influence of different junction temperatures and pressures on long-term aging failure is studied, revealing the evolution of key characteristic parameters during the aging process. Two main failure modes are identified under ac power cycling tests. One mode is caused by overvoltage short-circuit failure due to the blocking voltage drop, and the other is induced by open-circuit failure due to uncontrolled gate current. Finally, the evolution of microscopic morphology and static characteristic parameters over the entire lifetime during the power cycling test are obtained, emphasizing the differences between ac and direct current (dc) power cycling tests. The results show that there are significant differences in overheating failures between ac and dc power cycling tests, highlighting the critical role of ac conditions in failure analysis and reliability assessment. The study of the long-term failure evolution mechanism of the PP IGBT device under actual MMC working conditions aims to guide operational management, control protection, and device optimization design for the reliability of MMC systems.

关键词： Micro-channel heat sink   IGBT power module   Pin-fin heat sink   Ethylene-glycol   Heat transfer  

摘要： This study investigates the thermal coupling of a commercial Insulated Gate Bipolar Transistor (IGBT) power module with a micro-channel heat sink, focusing on pumping power and cooling performance across different designs. Three pin-fin geometries and four lid configurations were compared with a parallel rectangular channel design, all under identical dimensions and operating conditions. To reflect electric vehicle conditions, water-ethylene glycol mixtures at various concentrations were used as the working fluid. Results show that pin-fin heat sinks significantly outperform rectangular channels, lowering the module's peak temperature by approximately 30 degrees C and temperature non-uniformity by 25%. The proposed lid modification also reduces pumping power significantly without degrading thermal performance. Among all tested designs, the circular pin-fin heat sink with a second row of micro-channels and a thermally conductive lid (MCHS D4) is the most efficient, reducing thermal resistance by 77% compared to the base design and handling a maximum heat load of 687 W/cm2. However, increasing ethylene glycol concentration degrades performance, raising pumping power and thermal resistance by 38% and 43%, respectively. This work offers key insights into optimizing thermal management for power electronics by evaluating performance under near-realistic conditions.

关键词： 混合型步进电机   精确数学模型   力矩波动抑制   矢量控制  

摘要： 混合型步进电机磁路复杂且高度非线性，加之存在齿槽转矩，导致步进电机数学模型误差较大。这使得在伺服系统中，出现控制精度低、力矩波动大等问题。为解决上述问题，利用磁网络模型分析永磁磁链高次谐波，构建更精确的混合型步进电机数学模型，并采用数值计算方法验证模型的正确性。基于精确数学模型分析力矩波动特性，设计力矩波动抑制算法，并在Maxwell仿真软件中进行验证。所设计的抑制算法可将额定负载工况下的力矩波动降至1%以下。根据精确数学模型和力矩波动抑制算法，对传统矢量控制系统进行改进，并在Simulink/MATLAB软件中验证算法的有效性。仿真结果表明，永磁磁链高次谐波和齿槽转矩会引起控制系统较大的力矩波动，本文所设计的抑制算法可降低70%以上的力矩波动，显著提升系统的控制精度。

关键词： 双输出变换器   变频控制   移相控制   零电压开通  

摘要： 本文提出了一种新型高效双输出LLC谐振变换器，通过将传统LLC谐振变换器副边整流电路中的两个二极管替换成开关管，获得一个新的控制自由度—移相角。采用变频加移相控制策略，实现了两路输出的精确控制，且所有开关管都可以实现零电压开通、开关损耗小。本文详细分析了所提出变换器的工作原理和控制策略，并搭建了一台400W原理样机。通过原理样机实验验证了所提出拓扑及其控制方法的正确性和有效性。

关键词： magnetic field interference   multiple chips   press-pack IGBT   PCB RC sensor  

摘要： The high-power press-pack insulate gate bipolar transistor (IGBT) is the core device of a high-voltage converter. The current sharing and aging characteristics of many parallel chips in IGBT are critical issues regarding its operational reliability. The printed-circuit board Rogowski coil sensor (PCB RC) is a straightforward tool for measuring the d i /d t during the on/off transient process and studying the current sharing and aging characteristics of multiple chips in IGBT. Owing to the very narrow space between parallel chips and large conducted currents in IGBT, the magnetic field interference with the RC sensor from adjacent conductors must be seriously considered. Based on the partial inductance theory, the magnetic field interference from adjacent conductors is analysed in depth. A universal method of turns arrangement of rectangular PCB RC sensors for anti-interference from adjacent conductors is proposed. A PCB comprised of multiple parallel rectangular RC sensors is designed using this method. Under the double-pulse test, the magnetic interference from closely adjacent conductors can be reduced to only 0.56%, and the method's effectiveness is verified.

关键词： 配电网   电能质量   电压不平衡   光伏变流器   负序电压   最优控制   负序导纳控制  

摘要： 大量三相不平衡设备的并网将导致三相电压不平衡，严重威胁了配电网的电能质量。除专用电能质量治理设备外，利用配电网中光伏变流器的剩余容量进行不平衡电压的治理是抑制电能质量污染的有效方法。文中提出了利用三相分布式光伏变流器治理并网点不平衡电压的最优控制策略。首先，该问题被建模为一个考虑电路定理、电流限幅、功率平衡、功率振荡的优化问题；其次，分析了该问题物理约束的几何性质，得到了不同条件下可行域的边界和最优点的取值；然后，据此设计了最小化并网点负序电压的控制策略，该控制策略的实现不依赖电网阻抗信息，并可以保证光伏阵列输出最大可用功率；最后，通过硬件在环实验验证了所提控制方法的有效性。

关键词： IGBT   电磁干扰   有限元仿真   微扰理论   三维简化模型  

摘要： 火箭发射返回段电动伺服系统中绝缘栅双极晶体管（Insulated Gate Bipolar Transistor， IGBT）会产生大量电磁辐射，对火箭上传感器弱信号形成干扰。针对此问题，提出基于微扰理论的有限元快速建模方法，构建IGBT模块的简化模型，并仿真对比分析该简化模型与现有三维模型在计算精度与仿真效率上的差异。研究结果表明，所提IGBT有限元三维简化模型在保留关键特征的同时显著提高了仿真效率。