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关键词： Wire   Stress   Insulated gate bipolar transistors   Vibrations   Resonant frequency   Resonance   Three-dimensional displays   Shape   Finite element analysis   Solid modeling   Expected life   insulated gate bipolar transistor (IGBT) module   reliability   vibration  

摘要： This article presents a case study on a gel-filled insulated gate bipolar transistor (IGBT) module under mechanical vibration, focusing on its failure mechanism and proposing a life model. First, we used finite element analysis (FEA) with ANSYS to predict the critical stress points, which turned out to be the bond wire feet. Second, we validated these findings to a high degree through experimental tests using a vibrating chamber. In both approaches, a strong correlation is found between the failure rate and the vibration profile, where wear rate increases as one approaches the bond wires' resonance frequency. In experimental tests, all samples happened to fail at the same location, i.e., the upper side foot of terminal bond wires. This result matches the simulation predictions, as these bond wires are the ones with the lowest resonance frequency, hence the closest to the real-world vibrations. A comparison between simulation and experimental results suggest that silicone gel adds to the system a beneficial low-pass behavior that is expected to extend bond wires lifespan.

关键词： Collector-emitter voltage drop   IGBT package degradation   motor drive   online condition monitoring   state-of-health (SoH) monitoring   Collector-emitter voltage drop   IGBT package degradation   motor drive   online condition monitoring   state-of-health (SoH) monitoring  

摘要： The on-state collector-emitter voltage drop (v(CE,on) ) of an IGBT as an indicator for package-related failures has been very well studied in literature. To obtain measurements at the same condition consistently remains a challenge as v(CE,on) varies with the junction temperature and current levels other than at inflection-point current level (I-inflection). The measurement of the v(CE,on) at the evaluated I-inflection is effectively decoupled from the effect of junction temperature such that the true state-of-the-health of the IGBTs can be assessed independent of temperature influence on v(CE,on). In this article, a new method has been proposed for in situ evaluation of I-inflection in two-level IGBT-based three-phase ( 3 Phi ) ac motor drive without expensive pre-characterization of IGBTs. The key advantage of the proposed method is the in situ evaluation of I-inflection with existing hardware without lowering the dc-link bus voltage and shorting the two IGBTs on the same phase leg. The method eliminates the need for calibration using a parametric semiconductor analyzer and thus, provides an inexpensive and faster estimation of I-inflection.

关键词： 随机最优控制   线性二次   Riccati方程   turnpike性质  

摘要： 本文综合了作者及其合作者们的最新相关工作,概述了随机线性二次最优控制问题的一些研究进展.文章主题由密切相关的三部分组成,分别是有限时区上的随机线性二次最优控制,无限时区上的随机线性二次最优控制,以及随机线性二次最优控制的turnpike性质.

关键词： 三电平H桥   中性线环流   十五相   载波移相   高频振动抑制  

摘要： 载波移相技术是多相电机高频振动抑制的最有效方法之一，然而带中性线的三电平多相电机系统施加载波移相后，存在中性线电流异常增加问题。本文以十五相电机系统为例，通过电机磁动势解析建模揭示多相电机载波移相高频振动抑制机理；其次，结合变频器调制策略，厘清三电平变频器中性线对地电位变化规律；第三，查明多相变频器载波移相中性线电流异常突增原因，并提出一种变频器通道内各相依次载波移相的中性线环流抑制方法；最后，搭建三电平十五相电机系统仿真模型和试验平台，对本文研究的载波移相前后中性线对地电位变化规律及中性线电流抑制方法予以仿真和试验验证，结果表明理论分析、仿真和试验结果吻合良好，验证了中性线电流抑制方法的有效性。本文研究结论可为三电平多相电机系统中性线电流抑制提供一种解决思路。

关键词： 柔性直流输电   模块化多电平换流器   电磁辐射   驱动板卡   电磁散射   感应电压  

摘要： 模块化多电平变流器(modular multilevel converter，MMC)是柔性直流输电的核心装备，其安全可靠运行对于保障电力安全至关重要。换流阀中IGBT器件在开关过程中因高电压和大电流的快速投切产生强电磁干扰，影响低压控制电路的正常工作，严重时可导致系统故障。驱动板卡与高压大电流IGBT器件直接相接，为系统提供开关控制信号，是低压二次板卡中最易受干扰的单元。本研究将探讨换流阀子模块IGBT器件的电磁辐射以及驱动信号电压中的电磁干扰问题。首先，本文明确了驱动板与功率模块之间的距离远小于IGBT开关电磁波的波长，因此聚焦近场辐射问题展开。因驱动板卡上布局布线复杂且存在局部铺铜的情况，本文首次揭示了驱动板卡上的电磁辐射源由IGBT器件开关电磁源以及驱动板上铺铜所引起的电磁散射源所构成，呈多源互相作用特性。进一步地，本文以实际换流阀子模块为研究对象，通过不同开关工况下实验分析，全面且准确地获得了换流阀子模块的空间磁场在位置、频率和强度上的分布特性；验证了驱动板卡上电磁散射特性以及电磁散射和辐射共同作用下的驱动信号端口的感应电压。该研究不仅为MMC中驱动板卡的电磁辐射特性提供了实验数据，也将在一定程度上为其电磁兼容性设计和防护措施提供理论支持。

关键词： IGBT   Tomographic imaging   Semantic segmentation   Scanning acoustic microscopy (SAM)  

摘要： The Insulated Gate Bipolar Transistor (IGBT) is a crucial power semiconductor device, and the integrity of its internal structure directly influences both its electrical performance and long-term reliability. However, the precise semantic segmentation of IGBT ultrasonic tomographic images poses several challenges, primarily due to high-density noise interference and visual distortion caused by target warping. To address these challenges, this paper constructs a dedicated IGBT ultrasonic tomography (IUT) dataset using Scanning Acoustic Microscopy (SAM) and proposes a lightweight Multi-Scale Fusion Network (LMFNet) aimed at improving segmentation accuracy and processing efficiency in ultrasonic images analysis. LMFNet adopts a deep U-shaped encoder-decoder architecture, with the backbone designed using inverted residual blocks to optimize feature transmission while maintaining model compactness. Additionally, we introduce two flexible, plug-and-play modules: the Context Feature Fusion (CFF) module, which effectively integrates multi-scale contextual information at skip connection layers, and the Multi-Scale Perception Aggregation (MPA) module, which focuses on extracting and fusing multi-scale features at bottleneck layers. Experimental results demonstrate that LMFNet performs exceptionally well on the IUT dataset, significantly outperforming existing methods in terms of segmentation accuracy and model lightweighting performance.

关键词： J2摄动   小推力   空间碎片   碰撞规避   最优控制  

摘要： 碰撞规避问题已逐渐成为相关领域的研究热点之一。在J2摄动环境下，讨论了小推力卫星最优碰撞规避机动设计问题，并提出了卫星碰撞规避和返航机动过程的高效算法。碰撞概率的计算是在地心惯性坐标系中进行的，而能量和燃料的最优控制计算则是通过对碰撞概率进行约束来实现的。不同于脉冲机动，本文考虑了J2摄动以观察其对小推力机动设计最优控制的影响。采用协态变量初值归一化方法有效提高了间接法求解燃料最优碰撞规避问题的效率。文中给出了有无J2摄动条件下的能量和燃料最优控制的仿真结果，并进行了比较。结果表明了本算法的有效性，在该算例下，当考虑J2摄动时，预计燃料消耗比不考虑J2摄动时节省约22.3%。

关键词： 协同控制   交叉口   混行队列   遗传算法   最优控制  

摘要： 针对信号交叉口下的混行交通,以改善交叉口的通行环境为目标,设计了一种分层解耦的信号灯-混行队列协同控制方法。在上层信号灯控制研究中,选取交叉口车辆延误时间计算模型,以车辆平均延误时间最小为目标,提出基于遗传算法的交叉口信号灯上层控制策略;在下层混行队列控制研究中采用“1+N”模式,建立混行队列动力学模型,选取车辆能耗模型,以队列经济性最低为目标,提出基于最优控制的混行队列下层控制策略。在上、下层控制策略验证的基础上,对协同控制方法进行有效性和敏感性研究。研究结果表明,提出的协同控制方法在不同交通场景下,均能有效改善交叉口通行效率和车辆经济性;当最小绿灯时长和控制区长度的取值越小时,车辆平均延误时间和平均百公里油耗改善效果越好。

关键词： 隔膜泵   高压变频器   节能  

摘要： 本文通过分析化工行业活塞式隔膜泵的生产工艺,阐述了高压变频器在软启动,改善生产工艺,提高生产率,自动化控制,节能等方面的控制优势,展示了高压变频器在化工生产方面的应用前景。

关键词： 排除法   变频器   七段速   故障检修  

摘要： 变频器在现代工业自动化控制系统中扮演着重要角色,可以实现精确的速度调节和过程控制,满足复杂多变的生产需求。通过维护检修,确保变频器正常运行,有助于提升生产过程的自动化水平和设备稳定性。因此对其研究有重要意义。