汽车电动助力转向系统控制策略的研究

文章系统阐述了电动助力转向系统的控制策略和控制方法。通过比较电压控制方式和电流控制方式,得出电流控制方式明显优于电压控制方式的结论;并重点分析了在电流控制方式下的控制策略(包括助力控制、回正控制和阻尼控制),并在SIMULINK中进行了仿真。     

An assessment of UK drivers’ attitudes regarding the forthcoming ban on the sale of petrol and diesel vehicles

The purpose of the study was to predict how drivers of petrol or diesel cars might vote in a ‘Yes/No’ referendum concerning the UK government’s decision to ban from 2040 onwards the sale of all new non-electric vehicles. Five main factors were hypothesised to influence voting intention: a person’s (i) level of environmental concern, (ii) attitude towards electric cars (measured via an Implicit Association Test), (iii) belief about the importance of air pollution, (iv) driving requirements, and (v) reaction to the cost of the ban to the individual (assessed using a contingency valuation approach). The study also examined possible determinants of attitudes to electric vehicles, e.g., whether an individual was a ‘technology enthusiast’, had prior knowledge of and searched for knowledge about electric vehicles, and whether a person had played an online game where the player assumed the identity of an electric car driver. A structural equation model was developed and tested on a sample of 675 UK drivers, none of whom had ever owned or driven an electric car. The results suggested a good fit of the model to the data, except that neither environmental concern nor belief in the importance of clean air affected attitude to electric cars. Also, high levels of environmental concern did not motivate people to search for knowledge about electric vehicles. Social marketing campaigns that will be needed to precede the ban should focus on its health benefits, and not target particular age groups, gender, or whether a participant had children.     

二十一世纪的Azipod吊舱式电力推进系统

本文叙述了ABB公司的Azipod吊舱式电力推进技术及其发展历史，对一些采用Azipod系统的船舶的运行情况以及最新技术如CompactAzipod和CRP Azipod等的发展作了简要介绍。对电力推进系统中所需控制的关键参数和电站容量，推进为频器选型以及电网谐波畸变等的控制选择方法作了理论上的阐述。     

地铁杂散电流场的有限元模拟

为了研究地铁杂散电流场的分布规律及其影响范围,建立二维地铁杂散电流场数学模型,采用伽辽金有限单元法进行求解,根据有限元控制方程编制求解程序.对存在解析解的圆环域恒定电位场的模拟计算结果表明,该数学模型和计算程序是合理的可行的.对均匀介质、成层介质的地铁杂散电流场模拟计算结果表明:从地铁隧道到周围地下环境的电位都是非线性衰减的;距离地铁隧道越远,杂散电流强度越小;加大地铁隧道附近区域的电阻可以减小地铁杂散电流的影响范围.本文有限元模拟计算结果可作为确定杂散电流防护范围、定量评价地铁杂散电流对周围地下环境影响程度的依据.     

同步发电机整流系统的数学模型及稳定判据

将带整流负载同步发电机中各变量的d,q轴低频分量和高频分量分别处理，得出了小扰动条件下三相同步发电机整流系统的线性化模型及系统稳定判据，该模型可用于分析单机整流系统运行稳定性等问题。