基于模糊对向传播网络的PEMFC建模

质子交换膜燃料电池是由一种质子导体聚合电解膜构成的燃料电池,作为21世纪的绿色环保能源,对质子交换膜燃料电池进行输出特性研究有助于改善其性能,提高其工作效率。对于这种离散非线性系统,文章将神经网络和模糊控制技术相结合,设计出了一种以模糊神经网络自适应控制系统为核心的建模方法,它是由模糊对向传播（FCP）网络辨识器构成,仿真结果表明该模型可行,而且模型精度较高,从而为设计PEMFC实时控制系统奠定了一定的基础。     

变压器极化谱特征量与绝缘状态关系研究

油纸变压器绝缘介质特性复杂,为了研究绝缘介质弛豫响应与油纸绝缘时域极化谱特征量的内在关系,以便将电气特征量法应用于无损诊断变压器绝缘状态,通过建立变压器油纸绝缘等效电路模型,仿真分析了回复电压极化谱特性,并在仿真基础上研究了不同绝缘状态下油纸绝缘时域极化谱特征量变化规律。结论表明,时域响应回复电压极化谱特征量能有效评估油纸变压器绝缘状态的差异,测试结果验证了等效电路模型对绝缘系统极化过程的有效反映,分析出电路参数仿真变化对应的回复电压特征量变化规律,为运用回复电压测试技术无损诊断变压器绝缘状态奠定了理论基础。     

基于磁场的质子交换膜燃料电池故障诊断方法

故障诊断作为解决质子交换膜燃料电池（Proton exchange membrane fuel cell,PEMFC）的安全和寿命问题的重要途径之一,备受研究人员关注。然而在当前PEMFC诊断中,对其早期故障诊断的研究较少,而在亟需早期故障诊断以便及时进行维护控制的PEMFC应用领域,如燃料电池汽车等,在故障发生早期对其进行精确诊断极其重要。该文针对现有PEMFC早期故障诊断方法匮乏问题,提出一种基于磁场的PEMFC故障诊断方法。首先建立PEMFC三维仿真模型,研究燃料电池性能变化与其外部磁场间关联机制,在此基础上搭建燃料电池磁场检测系统,并构建卷积神经网络（Convolutional neural network,CNN）对采集的磁场数据进行分析,验证其在包括水淹、膜干等不同PEMFC故障中的早期诊断效果。结果表明,采用基于磁场数据和卷积神经网络的故障诊断方法,可实现燃料电池不同程度、不同类型故障的在线识别和早期诊断。研究结果验证了磁场数据用于PEMFC故障诊断的可行性,对促进PEMFC故障诊断方法进一步发展、提升PEMFC系统可靠性和耐久性具有重要意义。     

基于MEMS的压电微泵建模与优化

以压电驱动的无阀微泵为研究对象,根据扩张管/收缩管的压力损失系数和连续方程,建立了无阀微泵的理论模型。利用有限元分析软件,建立了无阀微泵有限元模型,进行了耦合场仿真分析。模拟并分析了不同边界条件下驱动电压、电压频率、泵膜厚度、压电薄膜厚度和压电材料对无阀微泵输出特性的影响。仿真结果显示,无阀微泵具有很好的整流特性,并且驱动电压越大,输出特性越好。在局部固定边界条件下,当压电薄膜上施加电场强度为500 V/mm的驱动电压时,存在最优的压电薄膜厚度,使得微泵的输出流量最大。研究结果为无阀微泵的优化设计提供了依据。     

质子交换膜燃料电池的一维气体扩散模型研究

目前对质子交换膜燃料电池(PEMFC)的系统性能进行分析时,多采用集总参数模型。它无法体现电池内部结构对系统性能的影响。本文建立了PEMFC沿膜厚方向的一维结构模型,通过分析在电池阴、阳极的气体扩散规律,研究气源压力、温度对电池输出电压的影响。通过与不同条件下的实验结果以及集总参数模型进行比较,本文的仿真结果更加符合实验结果,适用范围更广,可为车用燃料电池的优化和控制提供可靠依据。     

单管压电扫描器建模方法的研究及标定精度分析

文章对扫描探针显微镜中的单管压电执行器在x-y平面扫描的电压-位移特性进行了物理和数据分析,提出了一种新的基于采集数据的建模方法。仿真及实验证明,建立的模型能有效的消除扫描速度、扫描角度、非正交和耦合误差,提高了精度。避免了建模时对压电陶瓷内部机理（极化等）的分析,使模型参数的个数降低到很少,并对其标定精度进行了分析。该方法是一种在工程实践中非常实用的建模方法。     

基于SVPWM的永磁同步电动机系统建模与仿真

为实现永磁同步电动机（PMSM）的电压空间矢量控制,在分析永磁同步电动机数学模型的基础上,利用Matlab／Simulink建立了永磁同步电动机矢量控制系统的仿真模型。介绍了矢量控制的坐标变换。重点介绍了电压空间矢量脉宽调制（SVPWM）的控制原理和算法,给出了电压空间矢量脉宽调制在Simu．1ink环境下的实现方法。最后对整个控制系统进行了仿真研究,仿真结果证明了该控制模型的有效性。     

基于MATLAB的光伏电池建模方法的比较

光伏电池的数学模型分为原理模型和工程模型;基于SIMULINK仿真工具建立了两类数学模型的仿真模型,合理地选择参数,得出了光伏电池在不同工作环境下的输出特性曲线.分析比较了两类光伏电池模型特性曲线,仿真结果表明原理模型更精确,但未知参数较多,实用性较差;而工程模型参数少,精确度不高,实用性好.对工程模型精确度不高的原因进行了分析,研究了工程模型中修正系数的典型值,对修正系数的典型值进行调整,改善了工程模型输出特性曲线的精确度,提高了工程模型的通用性.     

基于双电压驱动下高速开关阀的特性研究

为了提高高速开关阀的响应特性,采用双电压驱动的控制方法。运用AMESim建立高速开关阀的动态仿真模型,仿真分析得出不同控制方法下（单电压驱动、双电压驱动）高速开关阀的动态特性曲线及其特征值,通过试验测试证实了仿真结果的可靠性。结果表明：当高压源为25 V时,双电压驱动下开关阀的吸合时间减少了28.3%,释放时间减少了44.2%。仿真分析基于该高速开关阀在工作因素不变的情况下,不同控制方法对其动态特性的影响,结果进一步证实了双电压驱动控制方法的优越性。     

基于SVPWM控制的无刷直流电机的建模与仿真

针对传统无刷直流电机（BLDCM）控制系统方波驱动转矩脉冲大等缺点,采用了基于电压空间矢量脉宽调制（SVPWM）控制方法的正弦波驱动永磁无刷直流电机控制系统,建立了两级三相无刷直流电机的数学模型,利用Matlab／Simulink中的电力系统仿真T具箱SimPow—erSystems建立了SVPWM控制下的无刷直流电机转速、电流双闭环控制系统的仿真模型。仿真结果表明,电压空间矢量控制下的无刷直流电机控制系统具有较好的静、动态特l生,同时该仿真结果也验证了SVPWM控制无届Ⅱ直流电机的有效性和仿真模型的正确性。     

不同参数对质子交换膜燃料电池输出特性的影响

针对质子交换膜燃料电池(Proton Exchange Membrane Fuel Cell,PEMFC)的性能主要受到物理参数影响的问题,通过FLUENT软件建立燃料电池动力学模型,以对物理参数进行研究,得到了直行多流道单体质子交换膜燃料电池的极化曲线并对输出性能进行对比。结果表明:升高工作温度、升高运行压力以及降低质子交换膜厚度均有助于提高燃料电池输出电压,改善燃料电池的性能。研究结论将为PEMFC的设计和实际应用操作提供参考。     

车用低压质子交换膜燃料电池电堆的半经验模型

首先介绍质子交换膜燃料电池建模的现状,然后结合车用情况采用半经验方法进行建模,主要从理论基础出发,简化电堆模型,从中推导出浓差项,提出浓差阻力的概念.根据车用低压电堆的工作条件,采用断电法来获取不同温度下电堆的欧姆损失,用线性拟合方法获得欧姆损失表达式.在保证其他操作条件不变的情况下,改变空气过量系数,通过比较电堆电压的变化情况,采用实数编码的遗传算法对试验数据进行拟合,获得浓差阻力系数的表达式.在获得欧姆、浓差损失的基础上,推导出电堆的活化损失表达式.最终获得车用低压质子交换膜燃料电池电堆的半经验模型,并采用建立的模型对20组不同温度和过量空气系数下的电堆输出电压进行计算,计算结果与实际测量值比较吻合,说明建模方法相当有效,模型精度达到系统优化和控制的要求.     

Coordinating IMC-PID and adaptive SMC controllers for a PEMFC

For a Proton Exchange Membrane Fuel Cell (PEMFC) power plant with a methanol reformer, the process parameters and power output are considered simultaneously to avoid violation of the constraints and to keep the fuel cell power plant safe and effective. In this paper, a novel coordinating scheme is proposed by combining an Internal Model Control (IMC) based PID Control and adaptive Sliding Mode Control (SMC). The IMC-PID controller is designed for the reformer of the fuel flow rate according to the expected first-order dynamic properties. The adaptive SMC controller of the fuel cell current has been designed using the constant plus proportional rate reaching law. The parameters of the SMC controller are adaptively tuned according to the response of the fuel flow rate control system. When the power output controller feeds back the current references to these two controllers, the coordinating controllers system works in a system-wide way. The simulation results of the PEMFC power plant demonstrate the effectiveness of the proposed method.     

运行参数的动态控制对100 kW燃料电池系统效率及稳定性的影响

质子交换膜燃料电池运行过程中的功率输出,电流、电压输出,运行温度,向燃料电池输送的燃料氢气及氧化剂空气的流量、温度、湿度,冷却流体温度等运行参数之间可实现动态关联控制,对提高燃料电池运行效率及稳定性有重大影响。当燃料电池发电系统由怠速状态转向输出状态时,要求向燃料电池供应的燃料氢气、空气、冷却流体的流量也发生变化,并对其他运行参数(例如湿度、温度)实施动态控制,不但满足燃料电池功率输出变化的要求,而且可以达到提高燃料电池发电系统自身的燃料效率与运行稳定性的目的。     

质子交换膜燃料电池水管理模型

水管理是质子交换膜燃料电池的关键技术之一。建立了包括电极扩散层模型、阴极催化剂层伪均质模型和质子交换膜水传递模型的一维稳态质子交换膜燃料电池水管理模型,得到的电池极化特性与试验结果吻合。在此基础上分析了电池温度和反应气体流量、压力、增湿温度和相对湿度等操作条件对电池性能的影响,为燃料电池发动机系统的仿真、优化和控制提供了一个良好的基础。     

Optimal operating points of PEM fuel cell model with RSM

The output power efficiency of the fuel cell system mainly depends on the required current, stack temperature, air excess ratio, hydrogen excess ratio, and inlet air humidity. Therefore, the operating conditions should be optimized to get maximum output power efficiency. In this paper, a dynamic model for the fuel cell stack was developed, which is comprised of a mass flow model, a gas diffusion layer model, a membrane hydration, and a stack voltage model. Experiments have been performed to calibrate the dynamic Polymer Electrolyte Membrane Fuel Cell (PEMFC) stack model. To achieve the maximum output power and the minimum use of hydrogen in a certain power condition, optimization was carried out using Response Surface Methodology (RSM) based on the proposed PEMFC stack model. Using the developed method, optimal operating conditions can be effectively selected in order to obtain minimum hydrogen consumption. This paper was recommended for publication in revised form by Associate Editor Tong Seop Kim Dong-Ji Xuan received his B.S. degree in Mechanical Engineering from Harbin Engineering University, China in 2000. He then received his M.S. degree in Mechanical Engineering from Chonnam National University, South Korea in 2006. Currently, he is a Ph.D. candidate of the Department of Mechanical Engineering, Chonnam National University, South Korea. His research interests include control and optimization of PEM fuel cell system, dynamics and control, and mechatronics. Zhen-Zhe Li received his B.S. degree in Mechanical Engineering from Yanbian University, China in 2002. He then received his M.S. degree in Aerospace Engineering from Konkuk University, South Korea in 2005 and his Ph.D. degree in Mechanical Engineering from Chonnam National University, South Korea in 2009. Dr. Li is currently a Researcher of the Department of Mechanical Engineering in Chonnam National University, South Korea. Dr. Li’s research interests include applied heat transfer, fluid mechanics, and optimal design of thermal and fluid systems. Jin-Wan Kim received his B.S. degree in Aerospace Engineering from Chosun University, South Korea in 1990. He then received his M.S. degree in Aerospace and Mechanical Engineering from Korea Aerospace University, South Korea in 2003 and his Ph.D degree in Mechanical Engineering from Chonnam National University, South Korea in 2008. He is currently a Post Doctor of the Department of Mechanical Engineering in Chonnam National University, South Korea. His research interests include control of hydraulic systems, dynamics and control, and mechatronics. Young-Bae Kim received his B.S. degree in Mechanical Design from Seoul National University, South Korea in 1980. He then received his M.S. degree in Mechanical Engineering from the Korean Advanced Institute of Science and Technology (KAIST), South Korea in 1982 and his Ph.D. degree in Mechanical Engineering from Texas A&M University, USA in 1990. Dr. Kim is currently a Professor of the School of Mechanical and Systems Engineering in Chonnam National University, South Korea. Dr. Kim’s research interests include mechatronics, dynamics and control, and fuel cell hybrid electric vehicle (FCHEV) systems.     

基于系统辨识的PEMFC温度非线性建模与预测

针对质子交换膜燃料电池(PEMFC)等一类具有严重非线性的复杂被控对象，提出一种基于模糊模型的模糊预测算法，并对PEMFC系统进行建模。在建模过程中，采用离线学习和在线修正辨识出对象的模糊模型。其中，模型的参数通过模糊聚类初始化和离线反向传播算法进行学习，必要时可通过在线调整后件参数，以使得模型的预测精度能满足实时控制的需要。仿真和实验结果表明了该模糊辨识建模方法具有建模简单、模型精度高等优点，亦证明了该算法的有效性和优越性。     

Multi-dimensional modeling of CO poisoning effects on proton exchange membrane fuel cells (PEMFCs)

Carbon monoxide (CO), which is preferentially absorbed on the platinum catalyst layer of a proton exchange membrane fuel cell (PEMFC), is extremely detrimental to cell performance. Essentially, the carbon monoxide absorption diminishes the cell’s performance by blocking and reducing the number of catalyst sites available for the hydrogen oxidation reaction. In order to obtain a full understanding of CO poisoning characteristics and remediate CO-poisoned PEMFCs, a CO poisoning numerical model is developed and incorporated into a fully three-dimensional electrochemical and transport coupled PEMFC model. By performing CFD numerical simulations, this paper clearly demonstrates the CO poisoning mechanisms and characteristics of PEMFCs. The predictive capability for CO poisoning effects enables us to find major contributors to CO tolerance in a PEMFC and thus successfully integrate CO-resistant fuel cell systems.