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关键词： Junctions   Temperature measurement   Insulated gate bipolar transistors   Predictive models   Reliability   Temperature sensors   Prediction algorithms   Improved sailfish optimization algorithm   insulated gate bipolar transistor   junction temperature prediction   support vector machine (SVM)  

摘要： This study improves the accuracy of junction temperature prediction, as the insulated gate bipolar transistor (IGBT) reliability is important for the safe operation of its working system due to junction temperature is limited in its actual performance and reliability. A model based on an improved sailfish optimization algorithm to optimize support vector machine (ISFO-SVM) is proposed to solve the problem that the junction temperature prediction accuracy is not high enough. The proposed algorithm is improved by adaptive nonlinear iterative factor, Le'vy flight and differential mutation strategy to optimize the support vector machine (SVM) internal parameters to predict junction temperature. The results indicate that ISFO-SVM performs better under the same evaluation indexes. The root mean squared error average value decreased by 67.189%, and the mean absolute percentage error average value decreased by 63.189%, compared with the sailfish optimization algorithm to optimize the SVM. The prediction error of ISFO-SVM is smaller and the error value is in the [-5 degree celsius, 5degree celsius] range accounting for 98.270% of the total test samples. ISFO-SVM has a higher fitting degree than the actual junction temperature and the R2 has reached 99.660%. The model predicts the junction temperature of IGBT modules and provides scientific guidance for system reliability evaluation to maintain safe and stable operation effectively.

关键词： CFD   IGBT   minichannels heat sink   thermal turbulence   V-shaped pin fin  

摘要： With the continuous advancements in new energy vehicle technology, the insulated gate bipolar transistor (IGBT) thermal properties have a direct impact on power system reliability. In this article, a minichannel heat sink with staggered V-shaped pin fins (SVPF) is investigated through both experimental and numerical approaches. Initially, the heat transfer performance of SVPF and conventional minichannel heat sink was analyzed using the CFD numerical simulation method. Subsequently, numerical and experimental validation was carried out by assessing the Nusselt number and turbulence characteristics of SVPF. Finally, an in-depth analysis was conducted to investigate the effects of SVPF geometric parameters on the turbulent characteristics and heat transfer performance of the minichannel heat sink. The results demonstrate that SVPF exhibits superior hydrothermal performance, which could maintain better heat transfer performance while simultaneously reducing the friction factor of minichannels. These findings provide valuable insights for the design of three-dimensional pin fins minichannels heat sink.

关键词： Timing circuits  

摘要： FS-IGBTs are widely used in various power applications due to their low conduction and low switching losses. However, as the cell pitch is further minimized, its high cell density induces high saturation current that deteriorates short-circuit ruggedness, which is essential for power applications such as welding machines and motor drives. In this paper, a 650V 75A FS-IGBT is designed and fabricated. By including dummy gate and emitter trench structures in the active gate and optimizing the layout of the three cell structures, the short-circuit characteristics of the device can be significantly improved. Verified by experimental tests, the device has both low saturation on-state voltage and strong short-circuit ruggedness. The fabricated FS-IGBT has a short-circuit withstand time of 10μs at room temperature and can withstand 5μs and 3μs at 100°C and 150°C respectively, which is up to the latest technology level of Infineon. © 2024, The Authors. All rights reserved.

关键词： PLC   变频器   电气自动化控制  

摘要： 在科学技术不断发展过程中,PLC 以及变频器也开始普遍应用在电气设备自动化控制领域,以促进电气设备充分发挥节能优势,提升设备运行安全性能,并加大电网保护力度,延长设备使用寿命,保障相关工作人员安全。在电气设备自动化控制中应用 PLC 和变频器,可使相关控制系统具有更高的数据存储能力,并可推进电气设备智能化发展。,为此,此文需要对PLC的技术和原理的优势来专项的对变频器的技术和其特点进行更加详细的分析,这样可以讨论出PLC和变频器是否能够实现电气自动化的控制和多项关键点。

关键词： 永磁同步电机   动态性能   全局快速终端   改进型指数趋近律   扰动补偿  

摘要： 为提升永磁同步电机(PMSM)的动态性能并抑制抖振问题,提出一种结合全局快速终端和扰动补偿观测器的矢量控制方法,该方法在速度环设计全局快速终端滑模控制器(GFTSMC)并结合改进型指数趋近律(IERL),进一步缩短了系统的响应时间,削弱了运动点在滑模面的抖振现象。为了对永磁同步电机运行过程中存在的扰动问题进行补偿,设计了改进型扩张状态观测器(ESO)对未知扰动进行观测并进行前馈补偿。同时设计了滑模位置观测器,实现了对位置信号的检测。仿真结果表明,该控制策略进一步提高了调速系统的响应速度,降低了稳态误差,增强了抗扰性能,同时能更准确检测转子位置,转速响应时间提升了0.043 s,转速最大误差从69.9下降至11.75 r/min。

关键词： 海洋石油平台   透平发电机   变频器  

摘要： 在新时期背景下,海洋资源勘探开采逐渐成为发展中重点内容。而海洋中丰富的油气资源成为主要开采对象。透平发电机作为海洋石油平台的心脏,其实际运行中通常需要利用变频器启动,由此保障变频器运行稳定性即成为海洋石油平台运维人员重点工作内容。基于此,本文首先对透平发电机运行原理进行分析,随后针对透平发电机变频故障主要类型及处理措施进行梳理总结,最后提出透平发电机变频器维修中需关注重点环节。

关键词： 风电系统   六相同步电机   矢量坐标变换   气隙磁链定向   矢量控制  

摘要： 风能是中国最具潜力的可再生能源之一,而影响风能转化应用的主要因素是风力发电机的控制方法及特性。针对风能转化应用过程中遇到的风力发电机控制方法难以实现对风能的有效捕获问题,提出一种基于气隙磁链定向的矢量控制技术,通过6s/2r矢量变换得到旋转坐标系下电机的数学模型;对气隙磁链定向矢量控制技术进行研究,设计电机电流电压混合磁链观测模型,实现对电机转矩与磁通的独立控制;以双Y移30°六相同步电机为例进行仿真分析。结果表明:所提技术在电机空载启动与突加负载时具有较好的稳态性能和动态性能,解决多相电机控制的非线性和耦合性,提高模型的通用性和快速性。

关键词： 永磁同步电机   直接转矩控制   比例谐振控制器  

摘要： 针对常规直接转矩控制(DTC)中转矩和磁链控制存在较大偏差的现象,从永磁同步电机(PMSM)数学模型的分析出发,在有效估算定子磁链和转矩的基础上,提出了基于空间矢量脉宽调制(SVM)的DTC策略;同时,利用比例谐振(PR)控制器能在静止坐标系下实现对交流信号无静差跟踪这一特性,将其引入控制系统可克服比例积分(PI)控制的不足。最终设计了一套基于双PR控制器的PMSM-SVM-DTC系统。通过与常规DTC仿真对比分析,证明该方案能有效减小磁链和转矩脉动,鲁棒性强,具有良好的动态响应特性。并进一步利用实验验证了方案的可行性和有效性,具备工程应用价值。

关键词： STM32   无位置传感器   矢量控制   滑模状态观测器  

摘要： 针对无刷直流电机在方波控制时效率低、转矩脉动大,以及位置传感器降低系统稳定性等问题,基于32位MCU STM32F103C8T6设计了一套无位置传感器矢量控制系统。该系统利用滑模状态观测器对电机转子位置及转速进行精确估计,并采用电流与速度双闭环矢量进行控制。测试显示,与传统方波驱动相比,电机运行噪声明显变小,且电流波形具有较高的正弦度。适用于空调、助力自行车等对噪声比较敏感的电器,同时成本低廉,有较高的市场应用价值。

关键词： 最大值原理   最优控制   Markov跳   倒向随机差分方程   Hamilton-Jacobi-Bellman方程  

摘要： 本文研究一类同时含有Markov跳过程和乘性噪声的离散时间非线性随机系统的最优控制问题,给出并证明了相应的最大值原理.首先,利用条件期望的平滑性,通过引入具有适应解的倒向随机差分方程,给出了带有线性差分方程约束的线性泛函的表示形式,并利用Riesz定理证明其唯一性.其次,对带Markov跳的非线性随机控制系统,利用针状变分法,对状态方程进行一阶变分,获得其变分所满足的线性差分方程.然后,在引入Hamilton函数的基础上,通过一对由倒向随机差分方程刻画的伴随方程,给出并证明了带有Markov跳的离散时间非线性随机最优控制问题的最大值原理,并给出该最优控制问题的一个充分条件和相应的Hamilton-Jacobi-Bellman方程.最后,通过一个实际例子说明了所提理论的实用性和可行性.