再论我国列车空气制动力计算参数的成套性原则

介绍我国客货列车空气制动力的计算参数.论述制动力计算中的基础制动装置计算传动效率、实算闸瓦压力和闸瓦实算摩擦系数的成套性.指出《列车牵引计算规程》规定的实算摩擦系数是根据实算闸瓦压力试验出来的,而试验时用的实算闸瓦压力又是按基础制动装置的计算传动效率计算的,所以在计算列车空气制动力时,其中的实算闸瓦压力必须用计算传动效率计算.否则不能得出正确的计算结果.     

高速动车组再生制动控制系统的研究与仿真

研究目的:制动控制是高速动车组安全运行的关键技术之一,也是动车组牵引传动系统的重要组成部分。高速动车组的制动系统采用再生制动和电气指令式空气制动相结合的方式。在所有制动方式中,再生制动是唯一一种向电网回馈能量的方式,日益成为交流传动动车组的首选制动方式。如何实现牵引、制动、恒速、惰行等不同控制方式之间的平滑切换、回馈电网的单位功率因数控制是再生制动控制系统的核心技术。本文以CRH2型动车组为研究对象,对动车组再生制动关键技术进行研究,研究成果对高速动车组牵引变流关键技术的消化、吸收、再创新具有一定参考价值。研究结论:(1)设计出一种基于双滞环调节的恒速控制器,实现动车组在0～250 km/h范围内任意速度下稳定运行。(2)仿真系统在动车组制动时能够实现能量的回馈和电网的单位功率因数控制,且可以按照特性曲线发出再生制动力指令,满足动车组运行要求。     

基于超级电容的再生制动能量吸收装置分析

为解决地铁接触网压因再生制动而升高的问题,以北京地铁13号线为例,利用制动特性曲线进行分析,仿真并计算出列车再生制动能量大小,以此为基础,设计储能系统的电容量等参数和储能阵列的串并联方式。利用Simulink仿真平台,模拟网压变化,对超级电容储能系统进行仿真分析,验证了系统功能的有效性,为实际工程提供了理论指导和依据。     

超级电容在地铁制动能量回收中的应用研究

针对机车启动、制动对直流母线电压的影响,提出一种基于超级电容的储能装置,该装置通过双向DC-DC变换器为列车提供牵引或者吸收再生制动过程的暂态能量,分析了超级电容储能系统充放电控制策略,搭建了一个750V直流电气化铁路仿真平台,仿真结果验证了超级电容储能系统能够维持直流母线电压稳定,有效地防止城市轨道交通供电系统中电力负荷波动和避免再生制动能量的浪费。     

SS_(4B)型机车DK-2空气制动柜检测试验台设计

为提升DK-2空气制动柜的试验检测手段,提高产品质量,研发了SS4B型机车空气制动柜综合检测试验台。文章介绍了试验台的结构与原理,同时阐述了软硬件设计。通过实际运用情况,证明该试验台性能良好,运行可靠,可应用于SS4改/SS4B型机车DK-2空气制动柜的检测试验。     

Advanced vehicle dynamics of heavy trucks with the perspective of road safety

ABSTRACT

This paper presents state-of-the art within advanced vehicle dynamics of heavy trucks with the perspective of road safety. The most common accidents with heavy trucks involved are truck against passenger cars. Safety critical situations are for example loss of control (such as rollover and lateral stability) and a majority of these occur during speed when cornering. Other critical situations are avoidance manoeuvre and road edge recovery. The dynamic behaviour of heavy trucks have significant differences compared to passenger cars and as a consequence, successful application of vehicle dynamic functions for enhanced safety of trucks might differ from the functions in passenger cars. Here, the differences between vehicle dynamics of heavy trucks and passenger cars are clarified. Advanced vehicle dynamics solutions with the perspective of road safety of trucks are presented, beginning with the topic vehicle stability, followed by the steering system, the braking system and driver assistance systems that differ in some way from that of passenger cars as well.     

Distributed and self-adaptive vehicle speed estimation in the composite braking case for four-wheel drive hybrid electric car

Considering the controllability and observability of the braking torques of the hub motor, Integrated Starter Generator (ISG), and hydraulic brake for four-wheel drive (4WD) hybrid electric cars, a distributed and self-adaptive vehicle speed estimation algorithm for different braking situations has been proposed by fully utilising the Electronic Stability Program (ESP) sensor signals and multiple powersource signals. Firstly, the simulation platform of a 4WD hybrid electric car was established, which integrates an electronic-hydraulic composited braking system model and its control strategy, a nonlinear seven degrees-of-freedom vehicle dynamics model, and the Burckhardt tyre model. Secondly, combining the braking torque signals with the ESP signals, self-adaptive unscented Kalman sub-filter and main-filter adaptable to the observation noise were, respectively, designed. Thirdly, the fusion rules for the sub-filters and master filter were proposed herein, and the estimation results were compared with the simulated value of a real vehicle speed. Finally, based on the hardware in-the-loop platform and by picking up the regenerative motor torque signals and wheel cylinder pressure signals, the proposed speed estimation algorithm was tested under the case of moderate braking on the highly adhesive road, and the case of Antilock Braking System (ABS) action on the slippery road, as well as the case of ABS action on the icy road. Test results show that the presented vehicle speed estimation algorithm has not only a high precision but also a strong adaptability in the composite braking case.     

An integrated control strategy for the composite braking system of an electric vehicle with independently driven axles

For an electric vehicle with independently driven axles, an integrated braking control strategy was proposed to coordinate the regenerative braking and the hydraulic braking. The integrated strategy includes three modes, namely the hybrid composite mode, the parallel composite mode and the pure hydraulic mode. For the hybrid composite mode and the parallel composite mode, the coefficients of distributing the braking force between the hydraulic braking and the two motors' regenerative braking were optimised offline, and the response surfaces related to the driving state parameters were established. Meanwhile, the six-sigma method was applied to deal with the uncertainty problems for reliability. Additionally, the pure hydraulic mode is activated to ensure the braking safety and stability when the predictive failure of the response surfaces occurs. Experimental results under given braking conditions showed that the braking requirements could be well met with high braking stability and energy regeneration rate, and the reliability of the braking strategy was guaranteed on general braking conditions.     

蒸汽动力装置回汽制动工况下倒车级动叶安全性分析

针对蒸汽动力船舶回汽制动工况下倒车汽轮机叶片的运行安全性问题,通过回汽制动工况下倒车汽轮机的变工况工作过程分析,建立回汽制动工况下倒车级动叶的弯曲应力模型,并基于Matlab-Simulink环境,建立倒车级动叶的弯曲应力的仿真模型.仿真结果表明,回汽制动工况下,采用理想制动策略时倒车级第二级动叶的弯曲应力会超过安全许用值,导致倒车汽轮机的损坏,影响蒸汽动力装置的安全运行,因此需对倒车汽轮机进汽阀开启的时机及幅度进行限制.