DF8BJ交流传动内燃机车的电传动系统工况分析

介绍了DF8BJ交流传动内燃机车的总体技术参数，电传动系统的技术特点，阐述了机车交流传动系统的牵引工况和制动工况的工作过程。性能试验表明，该车牵引电机、电器的维护工作量大为减少，且牵引性能优良。     

A new formulation of the understeer coefficient to relate yaw torque and vehicle handling

The handling behaviour of vehicles is an important property for its relation to performance and safety. In 1970s, Pacejka did the groundwork for an objective analysis introducing the handling diagram and the understeer coefficient. In more recent years, the understeer concept is still mentioned but the handling is actively managed by direct yaw control (DYC). In this paper an accurate analysis of the vehicle handling is carried out, considering also the effect of drive forces. This analysis brings to a new formulation of the understeer coefficient, which is almost equivalent to the classical one, but it can be obtained by quasi-steady-state manoeuvres. In addition, it relates the vehicle yaw torque to the understeer coefficient, filling up the gap between the classical handling approach and DYC. A multibody model of a Formula SAE car is then used to perform quasi-steady-state simulations in order to verify the effectiveness of the new formulation. Some vehicle set-ups and wheel drive arrangements are simulated and the results are discussed. In particular, the handling behaviours of the rear wheel drive (RWD) and the front wheel drive (FWD) architectures are compared, finding an apparently surprising result: for the analysed vehicle the FWD is less understeering than for RWD. The relation between the yaw torque and the understeer coefficient allows to understand this behaviour and opens-up the possibility for different yaw control strategies.     

城市轨道交通列车运行延误及其传播特点的仿真研究

城市轨道交通系统具有列车运行间隔小、站间距离短、车站线路布置比较简单等特点，一旦列车发生运行延误，其传播的速度快、影响范围大。本文在分析城市轨道交通列车运行延误发生的随机性特征的基础上，指出城市轨道交通列车运行延误具有直接性、快速性和双向性的特点以及基于这些特点的列车运行延误传播的两种表现形式，然后运用系统仿真的理论与方法，建立了基于列车运行图的城市轨道交通列车运行延误的仿真模型，通过设计合理的列车运行延误统计指标和仿真分析方案，以某城市轨道交通线路为背景进行仿真分析。通过仿真分析发现，列车运行延误及其传播主要与能力利用率、缓冲时间、备车数量以及辅助线数量等因素有关，并且这些参数之间应该保持一定的合理匹配关系。     

空间矢量调制的异步电机直接转矩控制新方案

介绍了一种基于负载角控制的直接转矩控制(DTC)新方法.使用简单方程获得控制算法,既易懂又易实现.利用空间矢量调制可以获得固定开关频率且转矩脉动较小.这种控制方法克服了传统DTC的最大缺陷.结果表明此方法的可行性,它在克服传统方法缺陷的同时获得良好的速度控制带宽.     

新型道岔电热除雪装置在城轨交通的应用

讲述了新型道岔电热除雪装置在津滨城市快速轨道交通的应用，以及在设计、安装过程中发现的一些问题，并寻找相应的解决办法。     

交流传动与交直传动电力机车的技术经济性对比

通过对SS9型机车和DJ型机车在外形、性能、维护及运行成本和收益等方面的对比分析，指出交直传动固有的缺点，说明交流传动是铁路牵引动力发展的方向。     

用于三点式逆变器的脉宽调制控制方法

介绍了用于三点式逆变器的若干控制方法，并阐述了两种改进的ＰＷＭ控制方法，新的ＰＷＭ方法能明显减逆变器输出电压诉谐波分量，试验结果也证实了这是一种降低电机脉动转矩和噪声的有效方法。     

电动车组技术特点及对客运经济的影响

简要介绍了国外电动车组的技术特点和发展形势，对动力分散型电动车组和动力集中塑电动车组进行了综合比较，结合特点阐述了电动车组技术对铁路客运经济的影响。     

DC1500V辅助变流器IGBT门极驱动电路

从DC1500V辅助变流器的特点出发，针对IGBT门极驱动单元开发过程中的一些问题，提出了行之有效的控制方案，并分析了这种驱动方式的工作原理及特点。试验结果表明，该方案很好地满足了DC1500V辅助变流器的控制要求。     

Comparing and presenting city-level transportation CO2 emissions using GIS

In 2011, the European Pollutant Release and Transfer Register (E-PRTR) inventory of diffuse emissions became available, providing data on a range of atmospheric emissions at a 5 km resolution across Europe. The data are produced from spatially disaggregated emissions totals for countries, and must be validated before being used at a sub-national level. The UK government maintains a 1 km resolution emissions inventory based on a bottom-up methodology by which a validation is possible. The UK National Atmospheric Emissions Inventory data are used to assess at what geographic scale the new E-PRTR data might be most useful. This paper compares the two data sets and estimates city-level transportation CO₂ emissions for 149 EU cities. We find that at a functional boundary level the two datasets match well.