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关键词： 新能源汽车   驱动电机控制系统   矢量控制  

摘要： 近年来,新能源汽车产业快速发展,驱动电机控制系统在提高新能源汽车动力性能、降低能耗方面发挥关键作用。然而,当前驱动电机控制系统存在诸多问题,制约了新能源汽车整体性能的提升。该文分析新能源汽车驱动电机控制系统的重要性和存在的问题,探讨基于矢量控制的新能源汽车驱动电机控制系统,为新能源汽车驱动电机控制系统的智能化、高性能化发展提供新的技术路线,从而进一步优化新能源汽车驱动电机控制系统,有效提升新能源汽车性能。

关键词： 无人机   时间最优与预测控制   参数在线辨识  

摘要： 针对传统方波驱动的无人机电机难以满足电力巡检领域的快速精准响应以及抗干扰能力的需求,开展无人机电机矢量驱动技术研究,主要针对表贴式永磁同步电机(SPMSM)矢量控制中传统电流环控制难以兼顾电流响应快速性与准确性的问题,提出一种带有参数辨识的时间最优与预测的电流环控制策略。为实现电流的快速响应,对电流环进行时间最优控制;为实现电流的精准响应,在时间最优控制的基础上对电流环进行预测控制;为避免电机参数扰动对电流环控制产生负面影响,研究基于模型参考自适应的电机参数在线辨识技术,对电机参数进行更新修正。实验结果表明,相比于传统PI控制,带有参数辨识的时间最优与预测控制能更好地兼顾电流响应的快速性与准确性,所提电流环控制策略具有良好的鲁棒性。

关键词： 空−地协同   执行器故障   预设时间编队   图博弈   最优控制  

摘要： 研究了发生执行器故障的无人机−无人车异构编队系统的层级预设时间最优编队控制问题.以保容错性能和收敛速度的优化控制为研究主线,以层级控制、图博弈理论和预设时间控制为技术基础,构建了一种预设时间最优容错控制算法.虚拟层设计了基于一致性跟踪误差和能量消耗的二次型性能指标函数,借助耦合哈密顿−雅克比−贝尔曼(Hanmilton-Jacobi-Bellman,HJB)方程和强化学习求解近似最优控制策略,实现多智能体的同步最优控制和交互纳什均衡.实际控制层基于最优信号并利用滑模控制和自适应技术,设计了预设时间容错跟踪控制器,实现对最优编队轨迹的有限时间跟踪.在保证全局收敛时间完全不依赖于系统的初始状态和控制器参数的同时,也有效实现对执行器故障参数的逼近.最后,通过仿真实验验证了所提控制策略的有效性.

关键词： 930E重型电动轮卡车   交流变频调速   逆变器   IGBT   光纤  

摘要： 930E卡车电气系统采用GE公司变频励磁控制系统,具有调速性能好、响应速度快、运行速度快的特点。介绍了930E重型卡车交流变频调速在电动轮卡车上的应用,为了解决常见的变频器故障,通过分析930E卡车变频控制的原理和一些常见的故障及处理方法,为了提高设备的可靠运行提供有用的参考。本文旨在对930E重型卡车变频器的常见故障进行系统的分析,并探讨相应的诊断与维修策略。

关键词： IGBT结温计算   热网络模型法   模块老化   双脉冲试验   有限元仿真  

摘要： 文中提出一种计及IGBT模块键合线与芯片焊料层老化的热网络法结温计算,基于Simulink对短时间尺度下损耗与结温的相互依赖关系进行更新,并分别通过双脉冲测试及有限元仿真修正长时间尺度下键合线与芯片焊料层老化对IGBT结温计算的影响,在此基础上,根据芯片焊料层不同老化状态下键合线的应力特征,实现两种老化模式的相互关联,较为准确地计算IGBT结温。最终利用试验平台与传统结温计算方法进行对比验证了所提结温计算方法的准确性。该结温计算方法有助于在实际运行工况及IGBT模块老化状态下精确计算结温。

关键词： Avalanche energy   doping concentration   positive differential resistance (PDR)   super-junction IGBT (SJBT)   unclamped inductive switching (UIS)  

摘要： Avalanche capability of the super-junction insulated gate bipolar transistor (SJ-IGBT) under unclamped inductive switching (UIS) stress is experimentally investigated through a standard avalanche energy tester, accompanied with conventional N-drift IGBTs as contrasts. Measured average failure currents of the N-drift insulated gate bipolar transistors (IGBTs) and SJ-IGBT are 2.7 and 7.8 A, respectively, and the corresponding avalanche energy is 36.5 and 307 mJ, respectively, where the active area of measured SJ-IGBT is just 39% of the N-drift one. The stronger avalanche capability of SJ-IGBT can be attributed to its positive differential resistance (PDR) within the avalanche current tested range in the breakdown I-V curve, instead of the negative differential resistance (NDR) in conventional N-drift IGBTs, thus the positive electrothermal feedback in N-drift IGBTs can be suppressed in SJ-IGBTs. The multicell UIS simulation points out that, avalanche current and heat of SJBTs are evenly distributed in SJ pillar before the avalanche failure occurs, instead of concentrating on one side of the drift region as in conventional N-drift IGBTs, which is the main reason for the higher avalanche current and energy of SJ-IGBT. In addition, both PDR characteristics and UIS failure current of SJ-IGBT are sensitive to pillar doping concentration, which indicates that the higher doping concentration of SJ-IGBT is the intrinsic cause for its more robust avalanche capability.

关键词： Brachytherapy   Image-guided   Utilization   Thailand  

摘要： 286

关键词： Capacitor voltage sorting sequence number   Diagnostic strategy   Modular multilevel converters   Open -circuit fault   Switching function  

摘要： Capacitor voltage deviations between two submodules (SMs) are always used as the diagnostic index for the insulated gate bipolar transistor (IGBT) open-circuit fault diagnosis in modular multilevel converters (MMCs). However, it is difficult to determine when MMCs operate in different conditions. To solve this issue, this article proposes a diagnostic strategy for IGBT open-circuit faults in MMCs based on improved diagnostic indices. First, two diagnostic indices, i.e., the concept of the count of periods during which the switching function is fixed (CSF) and capacitor voltage sorting sequence number (CSN) are proposed. On this basis, fault detection is implemented by judging the changing trend of the CSN in the SM whose CSF is the highest. The remaining malfunctioning SMs are located in turns by a similar process to fault detection. The proposed diagnostic indices show consistent faulty characteristics under different operating conditions, thus avoiding readjusting the threshold according to different operating conditions. In this sense, the proposed strategy can be easily used and promoted in different operating scenarios. Experimental results in a hardware-in-the-loop (HIL) platform verify the effectiveness of the proposed strategy.

关键词： Junctions   Insulated gate bipolar transistors   Temperature sensors   Logic gates   Voltage   Germanium   Power electronics   Extraction circuit   insulated gate bipolar transistor (IGBT)   junction temperature extraction   voltage integral over voltage rise period (VIVRP)  

摘要： In this article, a temperature-sensitive electrical parameter (TSEP) method for insulated gate bipolar transistor (IGBT) module junction temperature estimation based on voltage integral over voltage rise period (VIVRP) is proposed. First, combined with the principles of thermodynamic physics, the movement characteristics of internal carriers and holes are discussed, and the waveform of voltage and current during the turn-off process is studied. The feasibility of using voltage integral overvoltage period instead of voltage rise loss in junction temperature measurement is discussed and proved. At the beginning of the turn-off process, the holes in the IGBT almost remain in spatial and temporal distribution (the collector current IC remains constant), which leads the VIVRP to a cheaper TSEP method for junction temperature detection, without the high-frequency current detection equipment. Finally, the junction temperature model based on VIVRP and the extraction circuit of VIVRP are proposed. In addition, it is compared with the junction temperature detection method based on the voltage rise time and voltage rise loss. The results show that the junction temperature detection method based on VIVRP proposed in this article is detection with high precision and low cost.

关键词： Field programmable gate array   Three-phase inverter circuit   Switch characteristics   Real-time simulation  

摘要： The field of motor drive makes extensive use of electronic power modeling and simulation of three-phase IGBT full-bridge inverter circuits. The accuracy and computational efficiency of these models have a direct impact on the dependability of the motor control system. The majority of earlier research focused solely on static processes of turning on and off in IGBTs, disregarding the transient proesses that occur when three-phase IGBT full-bridge inverter circuits are switched at high frequencies. This has an impact on the circuits' accuracy in real-time simulation. Therefore, this paper proposes and builds a field-programmable logic gate array (FPGA)-based steady-state and transient dual-phase three-phase IGBT full-bridge inverter circuit model for the static and transient characteristics of the insulated gate bipolar transistor (IGBT) element in the circuit. Depending on whether or not the switching states of the six IGBTs in the three-phase IGBT fullbridge inverter circuit are altered, the simulation process is split into steady state and transient phases. In the steady state phase with large step size, the circuit is d iscretized using the binary L/ C approach. In the transient phase, the transient process is divided into several small-step-long time domains. Real-time simulation waveforms are generated by interleaving and combining the multistage fitting method's solution of the circuit's transient waveforms at tiny step lengths with the steady state phase. Finally, in order to demonstrate the accuracy of the circuit model in this work, the simulation results of the two-stage three-phase IGBT full-bridge inverter circuit model based on FPGA are compared with those of the conventional ideal model for waveform comparison and data analysis.