课程文献中心 更多>>

关键词： multi-physics coupling structure   active learning   IGBT   service life prediction  

摘要： An effective approach is proposed to evaluate the service life reliability of a multi-physics coupling structure of an insulated gate bipolar transistor (IGBT) module. The node-based smoothed finite element method with stabilization terms is firstly employed to construct an electrical-thermal-mechanical (ETM) coupling structure of the IGBT module, based on which the multi-physics responses can be accurately calculated to predict the service life of the IGBT module. By using the high-quality sample data obtained through the ETM coupling model, a Monte Carlo based active learning Kriging metamodel (AK-MCS) is developed to assess the service life reliability of the IGBT module, which can greatly reduce the computational cost needed by the surrogate model construction and reliability analysis. Numerical results show that the proposed ETM coupling structure can produce high-quality sample data of the IGBT dynamics and the AK-MCS machine learning technique can accurately estimate the service life reliability of the IGBT module.

关键词： 永磁同步电机   矢量控制   频域模型   谐振抑制  

摘要： 原矢量控制系统频域模型在直接用于高速、带载系统运行性能分析时存在较大的误差,对其构建理论及过程进行了重新分析。在指出误差产生根源的基础上,通过在系统数学模型中引入反电势和负载的作用,并削弱直轴电流对系统误差的影响,从而提出可以直接用于永磁同步电机矢量控制系统性能分析的扩展频域模型。此外,还研究了扩展频域模型在系统谐振抑制中的应用技术,给出了基于解析方法的系统谐振抑制前后的带宽以及谐振点与反谐振点的计算结果。通过验证,进一步利用超前校正网络技术,对抑制后的带宽进行恢复和扩展。研究表明:该扩展模型不仅性能分析误差小,而且可以用解析法直接获取系统的频率响应特性,克服了原模型在获取高速、带载条件下系统频率响应特性时依赖扫频试验方法的局限性。

关键词： 最优控制   奇异摄动   高超声速滑翔飞行器  

摘要： 针对使高超声速滑翔飞行器达到最大射程的实时在线计算问题,用奇异摄动方法推导生成了在线最优制导方案。首先,根据纵平面内二维运动假设条件建立滑翔器的动力学方程,并对其进行无量纲化。其次,根据状态变量的变化快慢将模型划分为三个时间尺度,采用奇异摄动法在三个尺度上分别求出零阶外解、一层内解和二层内解,整合得到过载近似解析表达式。最后,将所提方法与伪谱数值解法进行仿真对比。仿真结果表明,所提方法的精度在合理范围内,且计算时间大幅缩短,满足滑翔器最大射程的闭环在线最优控制。

关键词： 可控换相换流阀(CLCC)   IGBT   滤波器投切   电压扰动   换相失败  

摘要： 分析了交流滤波器投切对换流站交流系统电压的影响,并论述了可控换相换流阀(CLCC)技术原理,通过对比分析可控换相换流阀在上海A换流站的实践应用,论证了当交流滤波器投切引起三相交流电压畸变时,可控换相换流阀可成功抵御换相失败,为其他工程采用可控换相换流阀提供参考。

关键词： 自适应动态规划   积分强化学习   最优控制   动态面控制   积分型障碍Lyapunov函数   多智能体系统  

摘要： 本文对具有时变输出约束和未建模动态的不确定严格反馈非线性多智能体系统,提出了一种最优包含控制方法.利用一种新型积分型障碍Lyapunov函数处理输出约束,利用动态信号处理未建模动态,利用动态面控制方法设计前馈控制器,结合自适应动态规划和积分强化学习方法设计最优反馈控制器,利用神经网络在线逼近相应代价函数,并设计权重更新律.理论分析证明了所有跟随者的输出收敛到领导者生成的凸包中,全部跟随者组成的闭环系统是半全局一致最终有界的,同时,跟随者的输出保持在给定的约束集中,代价函数达到最小.仿真结果验证了所提出方法的有效性.

关键词： PLC   变频器   节能控制   系统设计  

摘要： 在工业自动化技术快速发展的背景下,变频器在电机控制领域的应用日益广泛。然而,传统变频器在控制精度和节能效果方面存在不足,因此研究基于PLC技术的变频器节能控制系统具有重要的现实意义和应用价值。文中探讨了基于PLC技术的变频器节能控制系统的模块设计,以提高控制精度,降低能耗,实现节能减排的目标。通过研究,希望能推动变频器技术的创新发展,支持工业领域的可持续发展。

关键词： 模流仿真   IGBT   外壳   嵌件注塑   端子偏移  

摘要： 随着科学技术的快速发展,计算机虚拟仿真技术在汽车、运动器材、建筑、电子产品等领域得到了广泛应用,不仅可以缩短的产品设计周期,也可以在中后期进行缺陷的优化。如IGBT的外壳此类产品,采用塑胶材料加金属端子做为嵌件进行注塑生产的方式,由于含嵌件的注塑其特殊性,在注塑过程中极易出现金属端子偏移的问题,而此问题在初期设计时没有考虑上,导致外壳成品发生不可接受的端子偏移量。利用模流仿真分析,针对IGBT的外壳端子偏移问题进行研究,给嵌件注塑外壳解决端子偏移问题提供支持。

关键词： 主动悬架   直线电机   结构优化   矢量控制   模糊比例-积分-微分(PID)  

摘要： 为了弥补汽车被动悬架没有主动控制力的缺陷,设计了一种基于传统被动悬架结构的直线电机式主动悬架。在被动悬架中加入直线电机,可以增加主动悬架的阻尼力,降低汽车的振动。首先,对直线电机的结构进行设计;其次,运用ANSYS/Maxwell磁场分析软件和控制变量法,优化直线电机各部分结构尺寸参数,结果表明,直线电机电磁推力的波动降低了83%,同时稳态推力提升了10%;最后,在MATLAB/Simulink软件中搭建直线电机式主动悬架的仿真模型,使用模糊比例-积分-微分(proportion integral differential,PID)对直线电机式主动悬架系统进行控制,分别在时域和频域进行分析,结果表明,相较于被动悬架,直线电机式主动悬架的车身加速度、悬架动挠度、轮胎动荷载都得到了有效抑制,车身加速度功率谱密度也有了大幅度的降低,有效地提高了车辆平顺性和操纵稳定性。

关键词： solder   fatigue life   reliability   finite element  

摘要： The interconnecting solder is a key control factor for the reliability of electronic power packaging because it highly affects the junction temperature of insulated-gate bipolar transistor (IGBT) modules and is prone to plasticity, creep, and other failure behaviors under temperature-change environments. In this paper, the interconnecting performance and fatigue life of five different kinds of solders such as SAC305, sintered silver, Au80Sn20, sintered copper, and pure In under direct current (DC), power cycle, and electro-thermal coupling complex environments were studied based on electro-thermal multi-physical field coupling finite element simulation method, respectively. Results show that the sintered silver owns the most outstanding thermal reliability and the DC operating junction temperature of the IGBT module after utilizing sintered silver solder is only 90.2 degrees C, which is nearly 15 degrees C lower than that of the IGBT module utilizing SAC305 solder. Furthermore, in the power cycle reliability test, the fatigue life of Au80Sn20 solder reaches a maximum of 3.26 x 107 cycles while the life of indium presents only 5.85 x 103 cycles, a difference of nearly four orders of magnitude. Finally, under the complex environment of electro-thermal coupling, the fatigue life of Au80Sn20 solder is also the largest at 1.9 x 106 cycles, while the smallest life of solder becomes SAC305 solder at 4.44 x 102 cycles. The results of this paper can provide a theoretical basis for solder selection and life prediction of the IGBT module, which is of great significance in improving the reliability of power electronic packaging.

关键词： Baseplate distortion   residual stress   component thickness   reflow temperature curve setting   material varieties  

摘要： The welding of a direct-bonded copper (DBC) substrate to the baseplate in insulated-gate bipolar transistor (IGBT) modules often induces distortion and residual stress within the baseplate, consequently impacting the operational reliability of the IGBT module. Therefore, a comprehensive analysis of the factors influencing baseplate distortion and residual stress during the reflow soldering process is imperative. This study employs a finite element simulation model to investigate the effects of varying thicknesses of IGBT module components, reflow temperature curve settings, and types of material on baseplate distortion and residual stress. The simulation results highlight that the material of the IGBT module components exerts the most substantial influence on baseplate distortion and residual stress, followed by component thickness, whereas the impact of the reflow temperature curve setting is comparatively minor. The analysis of these influencing factors offers valuable insights for optimizing component thickness selection, material choices for IGBT modules, and reflow temperature curve settings. Moreover, it serves as a practical guide for enhancing production processes and minimizing associated costs. [GRAPHICS] .