三祖异步电动机的制动

本文通过从机械制动和电气制动两方面,阐述了对三相异步电动机制动控制.其中,电气控制常用的方法有反接制动、能耗制动和再生发电制动几种.通过对比几种制动的特点及优缺点,了解各种制动方法适用的线路.     

高速列车空气制动原理及泄漏处理方法研究与应用

空气制动仍是目前我国普速列车制动方式的主体,对于高速列车,自动式电空制动系统中电能传送的只是开始和停止空气分配阀动作的信号,制动管空气压力仍由制动管通过压力空气传送。对列车制动系统的分类和工作原理及故障处理的研究,具有重大意义。对于空气制动系统,存在最多的故障就是泄漏,文中先介绍了制动系统中常见泄漏故障和简单处理方法,然后阐述了管路压力的快速查看方法及试验标准。     

浅议电机的制动方式及应用

在生产过程中,经常需要采取一些措施使电动机尽快停转,或者从某高速降到某低速运转,或者限制位能性负载在某一转速下稳定运转,这就是电动机的制动问题.在应用中,电机制动多采用电磁制动.这里主要讨论电磁制动中的反接制动、能耗制动和回馈制动.反接制动制动力强,制动迅速,控制电路简单,设备投资少;但制动准确性差,制动过程中冲击力强烈,易损坏传动部件.能耗制动方法属不可控,制动力矩有波动,但制动时间是可人为设定的.回馈制动是当采用有源逆变技术控制电机时,将制动时再生电能逆变为与电网同频率同相位的交流电回送电网,并将电能消耗在电网上从而实现制动.能量回馈装置系统具有的优越性远胜过能耗制动和反接制动.     

电动汽车电机制动防抱死模型研究

为解决电动汽车电机制动研究中仿真模型构建困难,建模方法复杂的问题.根据电机制动的运行机理,建立基于PWM全桥调制方式的永磁无刷直流电机电气制动模型,与电动汽车电气制动过程的动力学特性相结合,在Matlab/Simulink环境下建立了电动汽车电机制动仿真模型.系统采用模糊控制策略,通过占空比调节,控制电气制动电流,使滑移率保持在理想范围.仿真结果表明采用模糊控制策略能够可靠地实现电机制动防抱死的功能,系统模型运行平稳、反应灵敏.该模型可以用于电动汽车电机ABS不同控制策略的仿真研究,作为电动汽车制动动力学研究以及制动电气特性研究的基本模型.采用模块化设计方法,修改方便,避免了繁琐的建模工作,在电动汽车电机制动相关研究中具有较强的实用价值.     

电磁感应中涡流制动类试题分类剖析

电磁感应中涡流制动类试题在高中物理各类考试中常常出现.本文根据涡流制动线圈回路放置情形将电磁感应中涡流制动类试题分为涡流制动回路间隔放置类试题和涡流制动线圈连续放置类试题,分类剖析同类试题特点及其一般求解方法.     

谈汽车“制动不灵”的原因及检修方法

汽车制动系统是保证汽车行驶安全的主要操作系统之一,其技术状况的好坏直接影响到行车安全。正常的制动性能是踩一脚制动踏板灵敏有效之外,紧急制动时两前轮、两后轮的压印和拖印距离基本相等,车辆不跑偏,制动距离不增长。汽车制动不灵是指汽车在行驶中,将制动踏板踩到底后仍不见汽车立即减速或停车,制动距离长。目前汽车制动采用两种方式,即液压制动和气压制动。本文针对上述两种制动方式所存在的制动不灵的原因及检修方法进行分析和阐述。     

地铁车辆制动控制与纵向冲击

主要介绍了地铁车辆的两个评价指标：稳定性和舒适度。列车纵向冲动是列车运行质量的关键影响因素,分析了列车减速度和纵向冲击率对于稳定性和舒适度的影响。研究地铁列车制动减速度与列车冲击率之间的关系,提出了针对地铁制动系统空气制动和复合制动的制动控制方法,通过优化制动控制策略提高了稳定性和舒适度。     

汽车防抱死制动系统的故障特点及诊断排除方法探析

汽车 ABS 防抱死制动系统的使用提高了汽车的制动效能,且一直在不断地改进并增加新的功能,这些功能可以主动参与到行车过程中,以提高行车稳定性。制动辅助系统在紧急情况下对驾驶员的制动进行加强,在保持车辆操纵性的前提下,达到最短的制动距离。本文将对轿车 ABS 制动系统的故障特点和故障的诊断与排除方法展开分析。     

基于主成分分析的混合动力汽车复合制动舒适性分析

以混合动力汽车复合制动(电机前轴制动与液压制动)过程中驾乘人员舒适度定量评价为研究目标,通过主成分分析、加权主成分和价值函数,建立了基于样本的混合动力汽车复合制动舒适性评价模型,并通过多元回归方法建立了混合动力汽车制动舒适性与主成分间的回归方程,可对混合动力汽车的复合制动参数校调与整车制动过程中的舒适性进行预测和评价.分析表明主成分分析方法可以用于混合动力汽车复合制动的舒适性参数校调.     

通用变频器中制动功能的实现

详细介绍了通用型变频器中两种制动功能：再生制动和直流制动,并结合一种变频器设计给出了这两制动功能的具体实现方法,实验结果表明：变频器中设计的两种制动功能是可靠和有效的.     

Correcting Students’ Misconceptions about Automobile Braking Distances and Video Analysis Using Interactive Program Tracker

The present paper informs about an analysis of students’ conceptions about car braking distances and also presents one of the novel methods of learning: an interactive computer program Tracker that we used to analyse the process of braking of a car. The analysis of the students’ conceptions about car braking distances consisted in obtaining their estimates of these quantities before and after watching a video recording of a car braking from various initial speeds to a complete stop and subsequent application of mathematical statistics to the obtained sets of students’ answers. The results revealed that the difference between the value of the car braking distance estimated before watching the video and the real value of this distance was not caused by a random error but by a systematic error which was due to the incorrect students’ conceptions about the car braking process. Watching the video significantly improved the students’ estimates of the car braking distance, and we show that in this case, the difference between the estimated value and the real value of the car braking distance was due only to a random error, i.e. the students’ conceptions about the car braking process were corrected. Some of the students subsequently performed video analysis of the braking processes of cars of various brands and under various conditions by means of Tracker that gave them exact knowledge of the physical quantities, which characterize a motor vehicle braking. Interviewing some of these students brought very positive reactions to this novel method of learning.     

磁场减摩减磨技术应用于刹车装置的可行性分析

从机动车辆的刹车原理和刹车材料进行理论分析,将磁场施加于刹车装置,可以缩短刹车距离和刹车时间,同时延长刹车装置的使用寿命,磁场增摩减磨技术是改善机动车辆刹车装置的有效方法。     

Influence of baffle position on liquid sloshing during braking and turning of a tank truck

The influence of baffle position on liquid sloshing during the braking and turning of a tank truck was studied using a volume of fluid (VOF) model. The forces,their positions and weight distribution during braking and the forces and rolling moment during turning were calculated. The reliability of the calculation method was validated by comparisons with experimental results. The results showed that during braking,liquid splashes in the tank and the maximum forces and G (the ratio of weight acting on the front axle to the rear axle) are large when A (the ratio of the arch area above the baffle to the area of cross section)≤0.1. When A≥0.2,as the position of the baffle is lowered,the maximum of Fx (the force in direction x) first decreases then increases,and the maximum of Fy (the force in direction y) and G increase. During turning,liquid splashes in the tank and the maximum forces and M (the rolling moment) are large when D (the ratio of the arch area above the baffle to the area of cross section)≤0.2. When D≥0.3,as the position of the baffle is lowered,the maximums of Fy,Fz (the force in direction z) and M increase.     

纯电动汽车机电复合制动控制策略分析

为提高电动汽车能量利用率、改善车辆制动效果,依照制动踏板的不同工作状态,设计了一种并联制动控制策略。在制动踏板踩下的复合制动工况,按照相关制动法规对机械制动和再生制动进行合理分配;在滑行制动工况,以能量回收效率为目标函数,运用遗传算法优化电机在不同转速下的最佳制动转矩。分别在典型道路工况和常规制动工况下对该策略进行实车测试,结果表明:在中国轻型汽车行驶工况(CLTC-P)下,该策略的节能贡献度可达25.93%,在滑行制动工况能量回收效率较原车提升64.07%,车辆制动距离也有明显缩减。     

纯电驱动汽车再生制动与能量回收研究现状

针对降低纯电驱动汽车能耗的问题,以纯电驱动汽车为对象,阐述了再生制动原理,指出再生制动技术对于电动汽车发展的必要性．介绍了再生制动技术,对电动汽车再生制动系统中的储能方式进行了分类与优缺点综述．针对不同电动汽车的运行工况,对再生制动进行了分类,分析了几种典型的再生制动控制策略和实现方法,以及每种控制策略对能量回收的利用率．     

Design and analysis of the hybrid excitation rail eddy brake system of high-speed trains

Compared to the current eddy braking patterns using a single magnetic source, hybrid excitation rail eddy brakes have many advantages, such as controllability, energy saving, and various operating models. Considering the large braking power consumption of the high-speed train, a hybrid excitation rail eddy brake system, which is based on the principle of electromagnetic field, is proposed to fulfill the needs of safety and reliability. Then the working processes of the mechanical lifting system and electromagnetic system are demonstrated. With the electromagnetic system analyzed using the finite element method, the factors such as speed, air gap, and exciting current have influences on the braking force and attractive force. At last, the structure optimization of the brake system is discussed.     

ABB液压站原理及应用分析

ABB液压站是提升机制动系统的关键设备,是集机、液电一体的恒减速制动系统,由高性能、集成化的液压控制元件组成;通过对ABB液压系统恒减速控制制动系统和液压制动系统的原理分析可知,较好了改善了制动性能,有效地提高了提升机的安全性。为确保提升机安全可靠运行,加强系统维护,提高专业水平也必不可少。     

Influence of aerodynamic braking on the pressure wave of a crossing high-speed train

When aerodynamic braking works, the braking wings can change the flow field around the train, which may impact on the comfort and safety. Based on a sliding mesh, the pressure wave and flow field around high-speed trains with aerodynamic braking are analyzed. By comparing three typical intersection situations, the pressure wave of a high-speed train during braking (with or without aerodynamic braking) is studied. The analyses indicate that the pressure wave around the high-speed train body will change while using the aerodynamic braking, causing several pressure pulses on the surface of crossing high-speed trains. The distances between the pressure pulses are equal to the longitudinal distances of the brake wings, but the magnitudes of the fluctuations are less than those induced by the head of crossing trains. During the crossing, a train without aerodynamic braking will not impact the crossing train.     

面向智能车的新型电子液压制动系统设计与分析

针对传统液压制动系统应用场景受限的问题,面向智能车设计新型电子液压制动系统,由车辆配备的智能驾驶系统将制动信号传递给制动系统,制动系统由助力制动子系统和备份制动子系统组成,两系统之间通过单向导通梭阀完成解耦。利用系统硬件在环实验,分析电子液压制动系统的动态特性。实验结果表明:影响电子液压制动系统建压响应性与精度的因素众多,为使得系统可以快速响应,应确保整车制动管路排气良好,尽量避免使用制动软管?同时,不宜长时间进行高压力保压工况,避免电机及电机驱动器过热从而降低制动效能。     

基于AMESim的装载机液压制动系统设计与仿真

装载机向着重载高速智能化方向发展,对其制动系统提出了更高的要求.动力制动系统以其优越的制动性能及可靠性被广泛应用于工程装备领域.本文分析了全液压湿式制动系统的工作原理,根据简化后的制动系统工作原理,建立了全液压湿式制动系统的数学模型,并利用AMESim仿真平台搭建了全液压湿式制动系统的仿真模型.在此基础上对全液压湿式制动系统制动性能进行仿真分析.仿真结果表明:从制动盘与摩擦片开始接触,制动力上升时间为0.1 s,且制动力上升分为3个阶段,解除制动时制动压力下降时间也为0.1 s.蓄能器充满油液后,至下一次充液可以实施约4次制动.活塞在0.1 s的时间内便达到了极限位置0.8 mm.