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关键词： Thermal residual stress   Packaging warpage   Silver sintering   IGBT   Shear strength   Tomography  

摘要： Injection-moulded power electronics are inevitably subjected to warpage and residual stress from anisotropic contraction and thermal mismatch during the assembly, which deteriorates their reliability in service. In this work, the packaging warpage and residual stress of an epoxy resin encapsulated Insulating Gate Bipolar Transistor (IGBT) module were characterized with X-ray Computerized Tomography (CT) and blind-hole drilling, supported with Finite Element Analysis (FEA). Their effects on the bonding quality after silver-sintered to an external heat sink were investigated with Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), and mechanical tests. The module exhibited a maximum warpage of 420 & mu;m, which comprised a flexed midsection and localized bending at the edges of the internal circuit board. The residual stress distribution had high magnitudes up to -39 MPa near the edges and a nearly stress-free interior. The warpage had little effect on the chemical composition across the module-silver interface, but the area fraction of the sintering defects increased by 37.5%, and the mean shear strength dropped by 7.4 MPa compared to the warpage-free counterparts. This work characterized the negative influences of packaging warpage and located the critical geometrical features that dictated the warpage behaviours, providing valuable information for future design optimization.

关键词： Carrier stored trench-gate bipolar transistor (CSTBT)   hole path   temperature sensing  

摘要： A novel design for a low conduction loss car-rier stored trench-gate bipolar transistor (CSTBT) with hole path and temperature sensing is proposed. Dummy gate is surrounded by a deep p-well and an n(+) sense in floating p region is connected to the source to achieve real-time temperature sensing by applying reverse p-n junction. This design also helps to mitigate the electric field at the trench bottom. Moreover, the carrier stored (CS) layer can be heavily doped to obtain a lower ON-state voltage (VON), thus improving the hole blocking capability. During the turn-off process, the p-well around the dummy trench can serve as a hole path to reduce turn-off loss (EOFF). Simulation results demonstrate that in comparison with the conventional CSTBT (Con-CSTBT), the turn-off fall time (t(f)) and EOFF are lowered by 68.7% and 52.3% at the same V-ON of 1.54 V, respectively. Therefore, the proposed hole path CSTBT (HP-CSTBT) enables an effective and feasible approach toward real-time temperature sensing in power electronics. The proposed device features simple structure, low cost, and is fully compatible with the existing process. As such, it shows promising potential for practical applications.

关键词： Temperature measurement  

摘要： Evaluation of thermal field inside IGBT cells is important for the chip technical optimization, failure analysis and reliability prediction. However, there is a great difficulty in measuring the transient temperature field inside IGBT cells. In this work, a method of measuring the temperature distribution inside IGBT cells during switching was proposed combining with metallographic technology and Thermoreflectance Imaging (TRI). Firstly, the IGBT module was prepared to achieve a well longitudinal section and its electrical characteristics was verified. Subsequently, the double-pulse test was carried out on the IGBT sample and the temperature distributions along the ground section were measured by TRI. For comparison, a TCAD model was proposed and used for characterizing the electro-thermal behavior of IGBT cells. It dedicates well consistence between TRI measurements and TCAD simulations. The proposed method first achieves the direct temperature measurement inside the cells of power devices in micro-nano spatial and temporal scales. It may provide an effective tool for further works like TCAD modeling. © 2023, The Authors. All rights reserved.

关键词： 新能源汽车   智能定位广告   低碳定位广告   微分对策   最优控制   决策  

摘要： 双碳政策下新能源汽车正加速替代传统燃油车，而新能源汽车生产制造商不断寻求新能源汽车产品差异化，并通过不同广告策略来影响消费者对产品的选择。为此，本文研究双寡头下新能源汽车生产企业广告定位策略的竞争问题，通过建立最优控制方法下低碳定位广告策略和智能定位广告策略的决策模型，运用微分对策分别分析两家新能源汽车生产企业在势均力敌和非势均力敌下的最优广告投入效果和水平。研究结果表明，在势均力敌的情况下，两家新能源汽车企业随着时间推移，最优低碳定位广告效果水平逐步减少；而较小的新能源汽车企业的销售率，随时间推移而增加；对于较大的新能源汽车企业的销售率，其结果取决于市场份额和市场扩张的大小；较大的新能源汽车企业的最优智能定位广告水平，在最初阶段随时间增加而增加。在势力存在差异的情况下，若实力较强的新能源汽车企业在初期销售额较高时，两家新能源汽车企业智能定位广告水平效果差异不大；若两家新能源汽车企业在初期销售额差异很大时，在初期时，实力较弱的新能源汽车企业智能定位广告效果远高于其竞争对手，但随后实力较强的反超实力较弱的新能源汽车企业。

关键词： 互联电网   自动发电控制   区块链   随机控制   最优控制  

摘要： 为有效提高两区域互联电网质量,实现在单位响应时间内达到吞吐量阈值的要求,设计两区域互联电网自动发电量控制随机最优控制系统。硬件方面,设计了HF通道隔离设备的结构,通过EnOcean网关完成信息传递,利用信息物理系统控制器结合区块链作为控制系统的核心设备,分析区域电网质量;软件方面,利用区块链的前置节点和后置节点建立访问控制程序,通过动作选择序列完成随机最优控制。实验结果表明:所设计的系统在单位响应时间内吞吐量阈值为200 tps,满足阈值要求;引入10%白噪声后可以较好地控制负荷波动,确保输出信号不存在毛刺,保证随机控制性能。

关键词： 地浸采铀   Modbus通讯   变频器  

摘要： 自动化工控系统常应用于原地浸出采铀行业,随着地浸矿山生产中监测与控制设备的增多,传统模拟量通讯存在线路敷设成本高、I/O模块使用数量多等缺点。在内蒙古某地浸矿山井场控制系统中,采区变频器使用Modbus通讯方式,完成其参数的远程采集与控制,降低项目建设成本,实现了在地浸采铀监控中心远程一键式启/停变频器及频率调节,提高了工作效率。

关键词： 永磁同步电机   自抗扰控制   参数整定   乌鸦算法  

摘要： 为提高永磁同步电机的控制性能,设计了一种自抗扰控制器与改进ESO并联的永磁同步电机矢量控制系统。首先,利用光滑的非线性函数改进传统的ESO,提高其对信号的平滑处理能力,并将改进的ESO与ADRC并联,提高信号处理的准确率;然后,将系统的电磁转矩与负载误差、转速误差与时间积分主动补偿到电流环,提高系统的响应速度和抗干扰性;最后,利用乌鸦算法优化ADRC的参数,减少人工参数整定的复杂度。Simulink中的仿真结果表明,改进系统比ADRC和PI控制具有更好的鲁棒性和稳定性。

关键词： 四旋翼无人机   鲁棒跟踪控制   积分强化学习   最优控制   不确定性  

摘要： 针对系统模型动态不确定和受外部干扰的四旋翼无人机位置轨迹跟踪控制问题,提出一种新的基于积分强化学习的鲁棒轨迹跟踪控制方法。建立四旋翼无人机原系统与参考轨迹的增广系统,将四旋翼无人机的鲁棒轨迹跟踪问题转化为镇定问题。通过使用带有折扣因子的价值函数,将无人机增广系统的鲁棒镇定问题转化为四旋翼无人机的最优控制问题,从而兼顾到四旋翼无人机的跟踪误差和整体性能。基于积分强化学习方法,构建了单网络演员-评论家结构对最优价值函数进行估计,进而实现对四旋翼无人机控制器的在线求解。对四旋翼无人机系统跟踪误差的稳定性及单网络结构权值的收敛性进行了严格的数学证明,仿真结果验证了所设计控制方案的优越性和鲁棒性。

关键词： 故障   倾转旋翼机   最优控制   倾转过渡  

摘要： 倾转旋翼机操纵面故障后的安全高效应急操纵是避免飞行事故的重要环节。本文计算分析了倾转旋翼机遭遇不同作动器故障后倾转过渡的飞行轨迹和操纵优化。首先将倾转旋翼机不同舵面故障后的安全过渡倾转问题转换为最优控制问题,然后采用混合多重打靶法将最优控制问题离散为非线性规划问题,并进行数值求解。以XV-15为研究对象,面向基于最优控制模型的倾转过渡过程进行验证,随后注入舵面损伤、卡滞故障,计算并分析故障后的最优安全倾转过程和操纵策略。结果表明,当升降舵出现舵效损失时,飞行员需要增大纵向杆量输出,可完成动态倾转过渡,但随着损失增大,倾转过渡的操纵复杂度会提升;升降舵出现卡滞后,调节飞行速度,改变了倾转过渡路径,可完成正向倾转过渡。

关键词： 布尔控制网络   延迟   可控性   Mayer型最优控制   半张量  

摘要： 本文研究一类具有延迟模式的不完全布尔控制网络的控制问题.通过半张量积将系统转化为经典的布尔控制网络.在此框架下,研究了此系统的可控性和Mayer型最优控制.最后,给出了可控制性的充要条件和Mayer型最优控制的必要条件.其主要贡献是利用矩阵半张量积方法将系统转化为布尔控制网络代数,一定程度上克服了矩阵积维数的限制.