PC104微机的串行通信的网络在电厂中的应用

PC104作为一种嵌入式微机标准，目前正广泛的应用于各种工业应用领域，文章基于PC104系统串行总线，针对火力发电厂电站辅机的特点，建立一种网络化的振动监测与分析系统。     

基于PC104的电力谐波检测装置研制

针对电力部门对电网运行质量进行监测的要求,论述了利用基于PC104的嵌入式进行便携式电力谐波检测仪的研制。介绍了基于PC104的嵌入式电力谐波检测装置系统的设计方法,重点阐述了谐波检测系统的软、硬件构成和应用程序设计流程。测量系统集高速数据采集与处理、实时谐波含量计算、结果显示和网络通讯于一体,该仪器具有功能强大,操作方便的特点,测量精度达到了国标的要求。     

基于WorldFIP的机车网络控制系统平台的研制

简要介绍了WorldFIP现场总线的技术特点,详细分析了基于x86和VxWorks平台的WorldFIP总线技术在机车的车辆总线和列车总线上的原理和实现方法。     

基于C++Builder的FLASH动画在机车制动工况监测中的应用

针对数码管或发光二极管显示机车制动系统工况具有繁琐且不直观等缺点,通过比较分析确立了基于C Builder的FLASH动画显示方式。分析了FLASH动画的基本特点、图像显示方式以及动画生成方式,探讨了机车制动工况监测系统的基本工作原理,通过将FLASH动画嵌入C Builder程序中,较好地实现了机车制动工况监测功能。     

GK1C型机车自动换挡控制系统改造

分析了GK1C型机车换挡控制系统工作流程及现场反映出来的问题,并结合机车运用要求,对控制系统进行了改造,以满足机车操纵性和可靠性的需求.     

GK1IC型机车自动换挡控制系统改造

分析了GK1C型机车换挡控制系统工作流程及现场反映出来的问题,并结合机车运用要求,对控制系统进行了改造,以满足机车操纵性和可靠性的需求。     

SDD6型机车的控制系统

介绍了南车四方机车车辆有限公司出口非洲的SDD6型机车控制系统的组成、功能和工作原理,该系统采用PLC作为硬件,在国内机车控制系统的基础上结合非洲的实际情况作了适应性改进,可以实现多机重联运行,具有功能全,自动化程度高,人机交互方便,保护功能强大等特点。     

机车制动状态微机检测控制系统的研究与应用

从铁路运输生产实际出发,针对目前国产内燃、电力机车制动系统存在的不足,研究了一种可对机车制动状态进行实时检测控制的微机控制装置.提出了该系统总体设计思路,介绍了其主要特点、组成、工作原理和主要技术参数.该系统采用AT89C51单片机控制,通过对机车速度信号、制动缸压力信号、单元制动器状态信号、机车运行工况信号的采集处理,实现机车制动状态的实时检测显示,用语音报警提示司机可能发生的机车动轮弛缓等非正常情况,预防事故蔓延和扩大.     

陶瓷涂层在机车柴油机上的应用

1 引言由于陶瓷材料具有高温强度好、低导热、小密度、高弹性模量、好的抗摩擦磨损性能,因此从70年代起,世界各国对掏瓷材料在内燃机上的应用,出现一股研究热潮,尤其是在燃烧室和排气系统零部件上涂复一层陶瓷材料作为隔热层已进入实用阶段。 70年代初,我国也开始进行机车柴油机活塞顶陶瓷涂层的研制工作,虽然取得了降低活塞顶温度和减小活塞顶温度梯度的好效果,但在运用考核中,出现涂层碎裂掉块的问题。80年代初期起,又重新投入人力     

浅析再造流程在机车整备中的应用

通过对机车整备流程的分析,运用再造流程管理理论,提高机车质量、工作效率,降低机破发生率,增强机车整备的核心能力,保障铁路运输安全、平稳有序运行。     

不同燃油节能添加剂台架试验节能效率的差别分析

本文使用市场销售量较大的三种不同类型的燃油节能添加剂分别做了台架试验,通过燃油节能效率的对比,发现燃油节能添加剂在台架试验中所表现出来的节能效率低负荷下也不超过5%,但是各种添加剂之间的相对值差别很大,不同添加剂之间节油率相差2~7倍,探讨了不同类型的燃油节能添加剂在台架试验中节能效率差别的原因。     

Hydrogen circulation system model predictive control for polymer electrolyte membrane fuel cell-based electric vehicle application

Polymer electrolyte membrane fuel cell (PEMFC) is one of the promising solutions overcoming future energy crisis and environment pollution in the automotive industry. However, PEMFC is vulnerable to the circulation of hydrogen mass flow rate and pressure, which may cause the degradation of the PEMFC's anode components and reduction of output performance over time. Thus, the control of the hydrogen supply system draws attention currently and is critical for the durability and stability of the PEMFC system. In this study, a model predictive control (MPC) approach for hydrogen circulation system is developed to regulate the hydrogen flow circulating. A model of the hydrogen supply system that contains a flow control valve, a supply manifold, a return manifold and a hydrogen circulating pump is firstly developed to describe the behavior of the hydrogen mass flow dynamics in the PEMFC. Subsequently, a hydrogen circulating pump MPC scheme is designed based on the piecewise linearized model of hydrogen circulation as well as the switched MPC controllers. By predicting the pressure of the return manifold and the angle velocity of the pump, the proposed MPC approach can manipulate the hydrogen circulating pump to achieve efficient and stable operation of the PEMFC.     

Sliding-mode-based temperature regulation of a proton exchange membrane fuel cell test bench

The temperature regulation of a cooling system of a PEMFC (Proton Exchange Membrane Fuel Cell) test bench is studied in this paper. Because of the unique configuration which is dedicated for cold start experiments, the operation at nominal temperature is unstable with a simple PI controller. A sliding-based control strategy is applied to suppress the temperature fluctuation. Firstly the structure of the cooling system is demonstrated and the cause of temperature fluctuation is analyzed. Then, a physics-based model of the cooling system is proposed on the Matlab/Simulink platform and validated with experimental data. Based on the model, a Sliding-mode controller with Extended Kalman Filter (EKF) is designed to regulate the temperature. The simulation results showed that the controlled system performed satisfactorily. Furthermore, when applied to the real system, the controller's real-time performance fulfills the test bench criterion. Experimental data show that the coolant temperature at the outlet of the fuel cell stack is kept in a range within ±1 °C, disregarding the heat generated at various working condition.     

Study of nonlinear control schemes for an automotive traction PEM fuel cell system

To be practical in automotive traction applications, fuel cell systems must provide power output levels of performance that rival that of typical internal combustion engines. In so doing, transient behavior is one of the keys for success of fuel cell systems in vehicles. The focus of this paper is on the air/fuel supply subsystem in tracking an optimum variable pressurization and air flow for maximum system efficiency during load transients. The control-oriented model developed for this study considers electrochemistry, thermodynamics, and fluid flow principles for a 13-state, nonlinear model of a pressurized fuel cell system. For control purposes, a model reduction is performed, and several multi-variable control designs are examined. The first technique uses an observer-based linear optimum control which combines a feed-forward approach based on the steady-state plant inverse response, coupled to a multi-variable LQR feedback control. An extension of that approach, for control in the full nonlinear range of operation, leads to the second technique, nonlinear gain-scheduled control. Some enhancements were applied to overcome the fast variations in the scheduling variable. Finally, a rule-based, output feedback control, implemented with fuzzy logic, is coupled with a nonlinear feed-forward approach, and is examined under the same conditions applied to the first two techniques. The control designs developed are compared in simulation studies to investigate robustness to disturbance, time delay, and actuator limitations.     

Weighted fusion control for proton exchange membrane fuel cell system

Oxygen excess ratio (OER) is closely correlated with the power generation efficiency and dynamic performance of proton exchange membrane fuel cell (PEMFC) system. As OER changes with varying load, it is prone to oxygen starvation and slow response to OER reference value, and great challenges to OER control technology are brought. To this end, a dual closed-loop weighted fusion control for PEMFC system is proposed. The outer loop is utilized to obtain the optimal OER reference value, and the inner loop is utilized to track the OER reference value. This inner loop combines the merits of active disturbance rejection control (ADRC) algorithm and fuzzy self-tuned PID (FSTPID) method. Simulation results reveal that the proposed approach is superior to the other three methods in reducing the overshoot, settling time and avoiding oxygen starvation issues, and also in improving several key performance indices, such as integrated absolute error, settling time, etc.     

Regenerative energy control system for plug-in hydrogen fuel cell scooter

An intelligent control system was developed using simple control methodologies for an H₂-powered fuel cell scooter with the aid of a built-in microprocessor. This system increases the power input to drive a hydrogen fuel cell scooter, particularly during uphill conditions by running both the batteries and the fuel cell source in parallel. This system also improves the energy management of the scooter by recharging the battery using the fuel cell as well as automatic switching to the battery source when the hydrogen fuel cell is running low on hydrogen. This system was tested on a bench set simulating a 254 W hydrogen fuel cell stack equipped on a 200 W scooter. The test rig set-up depicts a practical scooter running on various load conditions. These results reflect the efficiencies of actual running conditions. The entire operation was embedded in a PICAXE-18 microcontroller for automatic switching between the batteries and the fuel cell source. An increase in the DC motor efficiency by 6 % has been shown. The uphill angle of the scooter has been increased by 19.3 %, which means the scooter would be able to travel on steeper hills. Copyright © 2007 John Wiley & Sons, Ltd.     

Predictive control of solid oxide fuel cell based on an improved Takagi-Sugeno fuzzy model

Thermal management of a solid oxide fuel cell (SOFC) stack essentially involves control of the temperature within a specific range in order to maintain good performance of the stack. In this paper, a nonlinear temperature predictive control algorithm based on an improved Takagi-Sugeon (T-S) fuzzy model is presented. The improved T-S fuzzy model can be identified by the training data and becomes a predictive model. The branch-and-bound method and the greedy algorithm are employed to set a discrete optimization and an initial upper boundary, respectively. Simulation results show the advantages of the model predictive control (MPC) based on the identified and improved T-S fuzzy model for an SOFC stack.     

Fuel sensor-less control of a liquid feed fuel cell system under steady load for portable applications

This study presents a novel fuel sensor-less control scheme for a liquid feed fuel cell system that does not rely on a fuel concentration sensor. The proposed approach simplifies the design and reduces the cost and complexity of a liquid feed fuel cell system, and is especially suited to portable power sources, of which the volume and weight are important. During the reaction of a fuel cell, the cell's operating characteristics, such as potential, current and power are measured to control the supply of fuel and regulate its concentration to optimize performance. Experiments were conducted to verify that the fuel sensor-less control algorithm is effective in the liquid feed fuel cell system.     

An algorithm for sensor-less fuel control of direct methanol fuel cells

We report an algorithm for real-time control of the fuel of a DMFC. The MEA voltage decay coefficients [e₁, e₂], and I-V-T, M′-I-T, and W′-I-T curves (where I is the current, V the voltage, T the temperature, and M′ and W′ the methanol and water consumption rates, respectively) of n fuels with specified methanol concentrations C_M,k (k = 1, 2,…, n) are pre-established and form (I,V,T), (M′,I,T), and (W′,I,T) surfaces for each C_M,k. The in situ measured (I,V,T)_u after voltage decay correction is applied to the n preset (I,V,T) surfaces to estimate C_M,u (the C_M corresponding to (I,V,T)_u) using an interpolation procedure. The C_M,u is then applied to the n preset (M′,I,T) and (W′,I,T) surfaces to estimate cumulated “methanol” and “water” consumed quantities . Thus in a real-time system, the C_M and total quantity of fuel can be controlled using the estimated C_M,u and cumulated “methanol” and “water” consumed quantities.