重载铁路牵引供电系统主要技术研究

通过对重载铁路牵引供电系统存在的电分相、谐波、负序及再生制动四个主要技术问题进行分析,给出了切实可行的解决方案,希望能为重载铁路事业的进一步发展提供一定的参考.     

关于电气化铁路负载对电网电能质量影响的研究

电气化铁路以牵引负载为主,这种负载基于大量电力电子器件工作,其运行会给供电网带来谐波超标、负序越限、低功率因数等问题,严重影响周边用户的用电权益。文章基于国家权威部门对京沪线电能质量测试结果,就电气化铁路负载对电网电能质量的副作用进行解析,同时从优化牵引技术、引入并联补偿技术等层面提出针对性解决方法,以期为推进铁路电气化而抛砖引玉。     

CRH2型动车组谐波电流分析及仿真

本文针对CRH2型动车组,分析了三电平四象限变流器的工作机理,并研究了其电流控制及中点电位平衡控制策略。基于双边傅立叶变换方法,给出了功率和网压已知时,四象限变流器二重化运行时的电流基波及谐波表达式,分析了谐波电流的分布规律,并且讨论了中点电位不平衡时对交流电流谐波的影响。采用Matlab／Simulink软件编制了CRH2型动车组的谐波电流仿真程序,研究比较了不同牵引、制动功率及牵引网网压条件下动车组注入牵引网的谐波电流。     

牵引供电区段车网耦合系统谐波电流分析及抑制策略

本文以哈大高铁西四牵引供电区段及CRH380BG型动车组车网耦合为研究对象,分析牵引网高低次谐波产生机理,建立了车网耦合系统的数学模型,对动车组不同位置不同工况谐波电流进行仿真分析。针对牵引供电区段谐波电流特性,提出基于阻波高通滤波器的抑制策略,对满功率动车组不同工况谐波电流抑制方案验证,为哈大高铁西四牵引供电区段谐波抑制问题提供了理论参考依据。     

SS4G型电力机车在直供式牵引供电系统中的谐波分析与测试

本文以SS4G型电力机车为例,建立SS4G型电力机车在直供式牵引供电系统中的数学模型;并对电力机车牵引工况主电路采用的不等分四段桥式整流电路进行分析;然后对可能产生谐波最多的SS4G型电力机车在第一段整流桥工作在牵引状态时进行了仿真分析,得出机车在此状态下的谐波电流分布特性;最后利用电能质量测试仪器U902对第一段整流桥工作在牵引状态时的谐波电流进行了现场测试,测试数据表明与仿真结果基本吻合,证明了论文的分析和仿真结果正确合理。     

电铁系统影响下的煤矿电网负序电流治理方案研究

随着电气化铁路系统的迅速发展,大量煤矿电网都与电铁牵引供电系统共网运行,由于电铁牵引负荷产生负序电流注入电网,其对煤矿电网的电能质量造成很大影响,影响煤矿电网的安全运行。本文结合山西某煤矿实际电网运行情况,测试、分析了与电气化铁路系统共网运行的煤矿电网负序电流特点,同时分析了现有有源负序治理方法的优缺点,并选取合适的算法集成于有源治理设备MARS中进行煤矿电网负序电流治理。最后利用仿真软件PSCAD/EMTDC进行仿真分析,验证其是有效可行的。     

电能质量问题浅谈

从电能质量的定义出发,介绍了评价电能质量的电压偏差、频率、三相电压不平衡、谐波、电压波动与闪变5个指标及相关国家标准。系统地阐述了电网中电能质量降低所产生的一系列危害,提出了提高电能质量的方法。     

医院谐波监测与治理

电能质量问题是当今的热点问题之一,谐波的危害对发电、供电、用电三方的影响越来越大,因而谐波对电能质量的影响不容忽视。随着社会的高速发展,医院引进的先进医疗设备与高精度仪器越来越多,而这些设备所产生的电能质量问题也越来越严重。所以,对医院设备的谐波监测与治理成为迫切的需要。从谐波治理的角度,分析谐波有效值和畸变率的关系,在理论上计算得出谐波减少能够节省的电量,并通过Matlab仿真对谐波治理前后的电压电流波形进行了比较分析。     

高速动车组车辆牵引供电系统继电器保护的分析

确保车辆牵引供电系统持续供电,才能保证高速动车组的正常运行.基于这种认识,本文对高速动车组车辆牵引供电系统的继电器保护配置问题展开了分析,结合不同供电方式对牵引网和变压器的继电保护方法进行了探讨,以便为关注这一话题的人们提供参考.     

基于VC的高速动车组温升计算软件开发

国内高速动车组对可靠性技术要求越来越高,系统关键设备的温升直接影响动车组的长期可靠性,研究温升问题具有重要意义。笔者介绍了基于VC++6.0开发的高速动车组温升计算软件,该软件采用嵌入式系统完成信号采集,采用以太网和socket完成服务器端与客户端之间的网络通信和数据传输,通过建立4QC整流器、逆变器、牵引电机和变压器的热模型最终实现了软件的温升实时计算和波形显示。实验结果表明,该软件界面简洁,操作简便,为高速动车组仿真系统提供了良好的温升模拟环境。     

PWM变流器在城市轨道交通再生制动中的应用

城市轨道交通机车制动时产生的制动能量,除一部分被正在取流的机车利用外,剩余的则会导致直流牵引网压升高。现阶段,由于普遍采用的是电阻制动,剩余的能量全部由电阻消耗,这样不仅造成了再生制动能量的利用率低,还会增加散热通风系统的负担。本文分析了将PWM变流器应用于城市轨道交通再生制动能量吸收,建立了系统数学模型,并在Matlab/Simulink环境下搭建了系统仿真模型。仿真结果验证了方案的可行性,并且具有功率因素较高、系统动态响应快和直流侧电压稳定性好等特点。     

A new two-quadrant zero-current transition converter for DC motor drives

A new two-quadrant (2Q) zero-current-transition (ZCT) converter with the capabilities of 2Q power flow and ZCT switching profile for DC motor drives is presented. It possesses the advantages that both the main and auxiliary switches can operate with zero-current switching (ZCS), reduced switching losses and stresses, minimum voltage and current stresses as well as minimum circulating energy during both the motoring and regenerating modes. It also offers simple circuit topology, minimum component count and low cost. This converter is particularly useful for DC traction systems in which both motoring and regenerative braking are desired to have high efficiency. The corresponding theoretical analysis and its high-efficiency performance are supported by both simulation and experimental results.     

逆变+电阻混合型再生制动逆变装置在城市轨道交通中的应用

针对地铁电阻耗能型再生制动装置不能达到能量再利用的目的,本文提出了逆变+电阻混合型逆变回馈装置用于动力照明的方案,介绍其控制原理、装置构成,建立基于Matklab/Simuink仿真模型。仿真结果表明,加入逆变回馈装置后,制动能置得到充分利用,同时还起到稳定牵引网网压的作用。     

基于超级电容的列车制动能量回收控制策略

针对列车电制动回馈能量回收与利用问题,文中通过分析列车运行特性,重点探究了列车运行过程与牵引网电压波动之间的关系。结合牵引变电所供电功率与列车用电功率动态不匹配特性,采用车载式制动能量回收利用系统的方案,提出了基于列车用电功率动态变化的超级电容充放电控制策略。该方案主要由超级电容串并联储能单元和双向DC-DC变换器组成。利用MATLAB进行建模仿真分析,结果表明,该控制策略在有效回收利用列车制动能量的同时抑制了牵引网电压波动,为列车制动能量回收与利用提供了有效的解决方案。     

Iterative learning control of antilock braking of electric and hybrid vehicles

Hybrid electric vehicles (HEVs) use multiple sources of power for propulsion which provides great ease and flexibility to achieve advanced controllability and additional driving performance. In this paper, the electric motor in HEV and electric vehicle (EV) propulsion systems is used to achieve antilock braking performance without a conventional antilock braking system (ABS). The paper illustrates that the antilock braking of HEV can be easily achieved using iterative learning control for various road conditions. A vehicle model, a slip ratio model, and a vehicle speed observer were developed to control the antilock performance of HEV during braking. Through iterative learning process, the motor torque is optimized to keep the tire slip ratio corresponding to the peak traction coefficient during braking. Simulations were performed on a compact size vehicle to validate the proposed control method. The control algorithm proposed in this paper may also be used for the ABS control of conventional vehicles.     

A 1.5-MW Seven-Cell Series-Stacked Converter as an Active Power Filter and Regeneration Converter for a DC Traction Substation

A prototype 1.5 MW series-stacked converter system was built and installed at a dc traction substation. The converter inverts energy generated by slowing an electric train using regenerative braking. The regenerated energy is fed into the local ac network at the dc substation. A secondary function of the converter is to perform active power filtering (APF) while a train is drawing power from the substation. The system's control is based on the instantaneous reactive power theory. An interleaved switching scheme was used to switch the seven-cell series-stacked converter, thus exploiting the natural balancing properties of the series-stacked converter. Results obtained from tests done show that both the APF and regeneration functions of the system were successfully implemented.      

Novel Regenerative Braking Control of Electric Power-Assisted Wheelchair for Safety Downhill Road Driving

This paper describes a novel regenerative braking control scheme of electric power-assisted wheelchairs for safety driving on downhill roads. The ldquoelectric power-assisted wheelchairrdquo which assists the driving force by electric motors is expected to be widely used as a mobility support system for elderly people and disabled people; however, it has no braking system to suppress the wheelchair's velocity and brings the dangerous and fearful driving particularly on downhill roads. Therefore, this paper proposes a novel safety and efficient driving control scheme based on the regenerative braking system. This paper applies the regenerative braking system with the step-up chopper circuit serially connecting two motors and realizes the velocity feedback control with the variable duty ratio so that it tracks the optimal velocity based on the minimum Jerk model. In addition, the dynamic braking system is also applied at the low-speed range instead of the regenerative braking in order to suppress the acceleration. Some driving experiments on the practical downhill roads show the effectiveness of the proposed control system.     

Vehicle Stability Enhancement of Four-Wheel-Drive Hybrid Electric Vehicle Using Rear Motor Control

A vehicle stability enhancement control algorithm for a four-wheel-drive hybrid electric vehicle (HEV) is proposed using rear motor driving, regenerative braking control, and electrohydraulic brake (EHB) control. A fuzzy-rule-based control algorithm is proposed, which generates the direct yaw moment to compensate for the errors of the sideslip angle and yaw rate. Performance of the vehicle stability control algorithm is evaluated using ADAMS and MATLAB Simulink cosimulations. HEV chassis elements such as the tires, suspension system, and steering system are modeled to describe the vehicle's dynamic behavior in more detail using ADAMS, whereas HEV power train elements such as the engine, motor, battery, and transmission are modeled using MATLAB Simulink with the control algorithm. It is found from the simulation results that the driving and regenerative braking at the rear motor is able to provide improved stability. In addition, better performance can be achieved by applying the driving and regenerative braking control, as well as EHB control.