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关键词： Efficiency  

摘要： IGBT modules typically employ the thermal grease between the baseplate and the heat sink to promote the heat dissipation efficiency, also known as thermal interface material (TIM). However, TIM aging significantly increases its thermal resistance, reducing module’s thermal efficiency and elevating the junction temperature, yet the traditional thermal network model (traditional model) cannot characterize this phenomenon. Herein, an improved model is proposed to account for TIM aging, enhancing the accuracy of the junction temperature by analyzing the heat transfer angle and the path. The influence of aging of thermal grease on the Transfer Coupling area, self-thermal and coupled thermal impedance is researched deeply, and a thermal impedance matrix is constructed. The proposed model enables effective computation of both self-thermal and coupled thermal impedances, and shows remarkable improvements in thermal modeling accuracy. © 2011-2012 IEEE.

关键词： 感应电机   多相电机   矢量控制   无速度传感器控制   参数辨识   模型参考自适应系统  

摘要： 五相感应电机是结构最简单的一种多相感应电机，具有低噪声、低转矩波动和高承载能力的优点，因此适用于高功率和可靠性要求的应用场合。针对速度编码器易受外界干扰的特点，构建一种应用于五相感应电机的模型参考自适应无速度传感器矢量控制系统，用以对转速进行辨识，实现五相感应电机的无速度传感器控制。随后，针对传统模型参考自适应系统的磁链电压参考模型易受定子电阻数值影响的问题，进一步构建基于模型参考自适应的双参数辨识系统，用以同时辨识转速与定子电阻，并对各自的自适应律选取进行推导。最后，在Simulink中对双参数辨识系统进行仿真验证。仿真结果表明，该系统在不同转速以及不同负载转矩工况下对转速的辨识性能良好，整体辨识基本无静差，仅有约9.7 r/min的稳态波动；在定子电阻突变时，空载工况下定子电阻的辨识误差能够保持在5%以内，半载工况的误差为8.7%，满载则为13.7%。

关键词： Insulated gate bipolar transistors   Resistance   Salt   Temperature measurement   Leakage currents   Humidity   Semiconductor device measurement   Circuit faults   Current measurement   Stress   Blocking resistance   conductive path   high humidity   insulated-gate bipolar transistor (IGBT)   marine environment   salt spray  

摘要： Currently, insulated-gate bipolar transistor (IGBT) modules are developing rapidly and have been used to operate in many different environments. However, when IGBT modules are used in marine environments, there is high humidity and salt spray in the environment. These environmental causes will result in the formation of conductive paths between the different interfaces (internal and external) of the IGBT module. Under the influence of high humidity and salt spray in the marine environment, the conductive path greatly reduces the blocking capability of the IGBT module and severely disrupts the IGBT module's stable operation. To address this issue, this article simulates marine environment experiments on IGBT modules by salt spray and high voltage, high humidity, high temperature, and reverse bias (HV-H3TRB) experiments. It turns out that after treatment in the marine environment, conductive channels are formed both inside and outside the IGBT module. This is equivalent to connecting a resistance in parallel outside the IGBT module. It makes blocking capacity decrease significantly. Therefore, this article establishes a nonlinear relationship between the blocking resistance and voltage of the IGBT module. It can measure the faulty resistance of the conductive paths of the IGBT modules. In practice, the blocking capability can be determined by measuring the leakage current of the IGBT modules through the relationship between the faulty resistance and the leakage current of the device. This can provide an important reference for the stable operation of IGBT modules in marine environments.

关键词： 无刷直流电机(BLDC)   矢量控制   模糊控制器   现场可编程门阵列(FPGA)  

摘要： 针对传统软件控制器存在响应速度慢、精度低和抗干扰能力差的问题，文章基于现场可编程门阵列(field programmable gate array, FPGA)实现无刷直流电机(brushless direct current motor, BLDC)模糊PI控制系统的设计。该控制系统内部采用全硬件实现方式，提高了系统的运算效率，增强了抗干扰能力；系统采用转速、电流双闭环控制，转速环采用模糊PI控制算法，相较于传统PI控制算法，提高了响应速度和控制精度。实验结果表明，文章设计的控制系统响应速度快、超调小、抗干扰能力强。

关键词： 新能源汽车   永磁同步电机   改进粒子群优化算法   矢量控制   鲁棒控制  

摘要： 永磁同步电机（PMSM）因其功率密度大、效率高、动态特性好、以及国内原材料丰富等优势,成为众多新能源车企的首选电机。车用永磁同步电机运行工况复杂,运行过程中容易受到外部和内部扰动。采用传统PI控制时,参数变化会导致系统难以实现精确控制。本文通过设计鲁棒控制器将一些干扰提前考虑进去,进而对永磁同步电机进行有效控制,并通过改进粒子群算法（IPSO）对加权函数进行寻优设计满足复杂工况下的鲁棒控制器。本文的主要研究内容如下: （1）分析PMSM种类和数学模型,采用id=0的矢量控制策略,基于Simulink搭建双闭环PI矢量控制仿真模型,验证PI控制系统下模型的准确性。 （2）针对传统粒子群优化算法收敛速度慢、易陷入局部最优的问题,从均值初始化粒子种群、引入动态学习因子和融合遗传算法三个维度对粒子群算法进行改进,通过多维测试函数验证改进后的粒子群优化算法的优势。 （3）构建全参数加权函数结构,通过改进粒子群算法对全参数加权函数寻优,计算出能提高控制系统静、动态性能和鲁棒性的控制器,并验证加权函数的有效性。在施加外部干扰和内部扰动的情况下,验证了在仿真模型下改进粒子群算法优化的鲁棒控制器较PI控制和传统鲁棒控制,具备更小的超调量、更快的响应速度和更强的鲁棒性,最后搭建硬件在环（HIL）仿真台架对鲁棒控制器的性能做基础功能性测试和稳定性验证。 仿真和试验表明:经改进后的粒子群优化算法在迭代速度和寻优精度都有所提高;通过改进粒子群算法优化的鲁棒控制器相比传统鲁棒和PI控制有着更好的响应特性,超调量较传统鲁棒控制的1.493%降低至0.397%;调节时间由0.03s缩短至0.02s。同时,在模型不确定性和外部干扰的情况下具备更好的鲁棒性。

关键词： 空间协同探测   轨迹优化   最优控制   智能优化   机器学习  

摘要： 面对未来大规模、复杂化、智能化航天任务发展趋势，针对空间目标协同探测任务中面临的轨迹优化难题，回顾了航天器轨迹优化的主要技术方法，包括最优控制方法、智能优化方法，以及机器学习方法的研究现状与进展。在此基础上，进一步探讨了以空间碎片清理、卫星对地观测、小天体探测、空间在轨服务等为代表的轨迹优化场景、任务设计问题与优化特性。最后，分析了现有研究存在的挑战，并展望了轨迹优化的设计需求，以期为未来复杂航天任务提供新的技术视角和解决方案。

关键词： 煤矿井下作业   PLC   变频器   调速恒压供水系统  

摘要： 煤矿井下作业过程中，基于井下作业需求和环境特点，保证供水系统恒压供水是关键。本文以某矿井井下消防供水系统为基础，基于PLC和变频器优势，提出调速恒压供水系统设计方案。该方案可以保证系统安全稳定运行，实现节能目标。

关键词： 最优控制   多层网络   谣言传播模型   随机知识传播模型   平稳分布  

摘要： 本文研究多层网络中一类谣言传播模型和一类随机知识传播模型的动力学行为及最优控制问题.全文共分为4章. 第一章,介绍传播模型和最优控制问题研究的背景、意义及现状,然后给出本文研究内容以及相关理论知识. 第二章,研究多层网络中一类谣言传播模型的动力学行为及最优控制问题.首先利用反证法证明了模型正解的存在唯一性;然后利用下一代矩阵法求出了基本再生数,并构建Lyapunov泛函证明了系统平衡点的稳定性;其次建立了模型的最优控制问题,证明了最优控制策略的存在性,并应用庞特里亚金极值原理得到了最优控制的具体表达形式;最后进行数值模拟. 第三章,研究多层网络中一类随机知识传播模型的动力学行为及最优控制问题.首先利用反证法证明了模型全局正解的存在唯一性;然后应用Has’minskii理论证明了模型存在唯一的平稳分布且该分布具有遍历性,得到了知识消亡和存续的充分条件;进一步建立了随机模型的最优控制问题并得到了最优控制策略的具体形式;最后进行数值模拟. 第四章,对本文进行总结,并给出了研究展望.

关键词： Dc-dc power converters   lifetime estimation   solar energy   solar energy   solar panels   solar panels   wind turbines   wind turbines   yield estimation   yield estimation   yield estimation  

摘要： With the growing adoption of renewable energy, hybrid wind-solar plants are gaining interest because they allow the increase of energy yield per unit of surface area. However, the presence of wind turbines creates unique shading scenarios for the solar panels. This work presents a simulation-based approach to investigate the solar plant's energy yield and converter IGBT lifetime in the presence of dynamic and fast-moving shadows created by the wind turbine blades. First, the need for a dynamic simulation as opposed to a static one is examined. Next, the sensitivity of Photovoltaic (PV) string orientation, PV string location, wind direction, Maximum Power Point Tracker (MPPT) control speed, and turbine rotor speeds on energy yield and IGBT lifetime are investigated in a case study. Results show that dynamic and static simulations can show vastly different results. MPPT can have difficulty with shadow flicker, resulting in different string voltages depending on the MPPT update speed and wind turbine rotor speed. The shadow flicker introduces additional temperature swings in the IGBT, but these are too small to add any significant lifetime consumption (<1.2%). Thus, the observed changes in lifetime consumption are caused mainly by controller behavior and static shadows. Finally, it is concluded that PV strings are better placed south, east, or west of the wind turbine for optimal energy yield and lifetime consumption. A northern placement can be suitable if there is a significant distance (+50 m) between the PV string and the wind turbine.