Running characteristics of the superconducting magnetically levitated train in the case of superconducting coil quenching

A superconducting (SC) magnetically levitated (Maglev) transportation system has been developed in Japan and various experiments have been done on the new test line in Yamanashi prefecture. Although the superconducting electrodynamic suspension (EDS) system has the advantage of stable levitation without active control, various electromagnetic or mechanical disturbances can change the gap length and cause the displacement or oscillation of the bogie. In this system, the severest disturbance is SC coil quenching. Therefore, it is important to determine the running characteristics of the Maglev train and to increase the stability in this case. We developed a three‐dimensional numerical simulation program for the Maglev train. Using this program, a running simulation of the train for the Yamanashi new test track was undertaken in the case of SC coil quenching. Because of the damping characteristics of the EDS system, the influence of coil quenching is smaller at higher speeds. In the train model, the electromagnetic spring strength of the EDS system is larger than that of the mechanical spring of the secondary suspension system connecting the bogie and cabin. Therefore, influence of the quenching is only seen in the cabins connected to the quenched bogie. Demagnetization of the SC coil quenching is considered to increase the stability of the train. Although this method is useful to decrease large guidance force, lateral displacement, yaw and roll angle of the bogie, vertical displacement, and pitch angle become large. © 1999 Scripta Technica, Electr Eng Jpn, 130(1): 95–105, 2000     

Magnetic characteristics of electromagnetic levitation system for short‐radius curve track

A magnetically levitated (MAGLEV) vehicle using electromagnets and iron rails generates lateral guiding force naturally by controlling levitation force to maintain the air gaps between the magnets and the iron rails. A MAGLEV system without guide magnets offers simple design and cost advantages. But such a system has little lateral damping force. In order to improve damping characteristics, an experimental apparatus using salient‐pole‐type magnets and laminated iron rails was made. The iron cores were placed in two rows. The suspension coils surrounded both of the magnet iron cores and the damping coils surrounded every magnet core separately. The damping coils were excited by currents proportional to the lateral displacement velocity. According to a step response experiment, the lateral motion dissipated after a cycle or two of the swing. The self‐inductance of the suspension coil of the magnet was almost unchanged against variation of the lateral displacement. The influence of damping current on the levitation was very small. This paper discusses the electromagnetic characteristics of the levitation system. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 156(3): 71–80, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20372     

Generation of method AC Ampere force using eddy current inside a nonmagnetic thin plate and its effect on electrodynamic suspension

In this paper, we propose a novel method for magnetic levitation force generation. In our method, we utilized three AC electromagnets that generate the inductive and AC Ampere forces. One electromagnet is installed above the surface and the other two in both sides of thin plate. Phase conditions providing the maximum levitation force are derived from 2‐dimensional finite element analysis. In order to confirm the performance of the proposed method, we performed some experiments. The experimental results show that in difference from conventional AC methods, the magnetic levitation force is increased around 5.9 times for the same eddy current inside the aluminum plate. In addition, the relations between excitation frequency, plate thickness and total levitation force are explained in details. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 170(3): 48–56, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20905     

板式双边永磁电动悬浮电磁力计算

针对现有电动悬浮模式的缺点,研究了一种由导体板和双边Halbach永磁阵列构成的悬浮系统。相比单边电动悬浮,该系统电磁阻力更小,适用于城市轨道交通。分别采用解析法和有限元法对其产生的电磁力进行计算。首先,建立了空间矢量磁位方程,通过求解该方程可得导体板中涡流分布;其次,研究了空间磁场与涡流的相互作用,得到了电磁力的2D解析表达式,建立了2D和3D有限元模型,计算了不同速度下的电磁力、磁场与涡流,并得出解析法与2D有限元法的平均相对误差为1.7%;最后,通过与单边电动悬浮对比,证明了该悬浮模式可有效提高浮阻比,减小阻力损耗。     

基于广义需求侧资源聚合的电力系统短期负荷预测模型

需求响应计划的广泛实施对电力系统短期负荷预测将产生一定的影响。为了获得理想的预测精度,需要准确计及需求响应因素的实时变化,并将其融入短期负荷预测模型的构建中。首先提出了一种能够通过电价合同实现的需求响应调度方式,该方式借助负荷聚合商机构实现了广义需求侧资源的最优调度,并能够以需求响应信号的形式提供给系统调度员利用。以此为基础,构建了基于广义需求侧资源聚合的电力系统短期负荷预测模型,将需求响应因素融入到短期负荷预测模型的构建中。仿真结果表明,构建的短期负荷预测模型能够有效弥补传统负荷预测模型的不足,有利于提升模型的预测精度。     

气浮悬挂系统电磁力补偿装置分析及优化

针对气浮悬挂装置运动过程中的气压波动和惯性力补偿问题,提出一种电磁力补偿装置,通过钕铁硼磁体产生磁场,设计了合理的磁路。应用Maxwell对该装置进行磁场仿真,通过对比及分析,优化了导磁材料的尺寸和结构,使有效行程内气隙中磁感应强度保持恒定,控制线圈回路中的电流产生需要的电磁力,补偿气压力与目标力的差值和惯性力。     

苏州同里±10 kV柔性直流配电系统直流故障特性研究

基于苏州同里±10 kV直流配电系统参数,针对直流单极接地和极间短路故障暂态特性进行了研究。采用示范工程系统结构及控制策略,利用PSCAD建立了电磁暂态模型,针对系统交流侧、换流器侧、直流侧和负荷侧进行了故障过电压、过电流研究,分析了接地电阻对直流侧电压和电流的影响。结果表明：系统直流侧发生单极接地故障时,交流侧出现持续直流分量,换流器不闭锁,DC-DC变换器高压侧电容放电;故障接地电阻对直流侧电压、电流影响大;极间短路故障产生严重过电流,将触发换流器过电流保护,导致换流器闭锁;故障电流是产生过电压的重要原因;电感元件两端过电压较大,极间故障对系统交流侧影响较小。     

Magnetic damping of the electrodynamic suspension‐type superconducting levitation system

The damping characteristic of the bogie motion is one of the most important issues to be investigated in the superconducting magnetically levitated system based on electrodynamic suspension (EDS). We have therefore studied the damping characteristics and the mechanism of magnetic damping. Electric circuits consisting of coil resistances and inductances can describe the electromagnetic behavior of the levitation system. By numerical calculation based on the electric‐circuit equations combined with the equations of motion, damping characteristics of the bogie are examined for the system consisting only of levitation coils and superconducting coils, and also for the configuration with magnetic shielding structures incorporated. Furthermore, paying attention to the energy balance in the levitation and propulsion system when the bogie is forced to oscillate sinusoidally, we have investigated the relation between the input energy and the running speed, and compared the waveforms of levitation force and bogie oscillation to consider the characteristics and the mechanism of the damping. © 1999 Scripta Technica, Electr Eng Jpn, 127(2): 49–60, 1999     

企业客户侧管理系统的优化

单纯的电力负荷控制系统已不能满足当前用电管理的需要,因此,建立用电现场服务与管理系统显得尤为必要。立足于实现并优化企业自身的需求侧管理,详细介绍了电力客户侧管理系统的结构,以及该系统如何帮助客户进行合理有序用电、监测用电需量、有效控制需量的最大值等内容,为企业实现负荷监测、调整峰谷用电量、提高用电效率提供技术支持。     

A study of economic evaluation of demand‐side energy storage system in consideration of market clearing price

In Japan the electricity market will open on April 1, 2004. Electric utility, Power Producer and Supplier (PPS), and Load Service Entity (LSE) will join the electricity market. LSEs purchase electricity based on the Market Clearing Price (:MCP) from the electricity market. LSEs supply electricity to the customers that contracted with the LSEs on a certain electricity price, and one to the customers that introduced Energy Storage System (:ES) on a time‐of‐use pricing. It is difficult for LSEs to estimate whether they have any incentive to promote customers to introduce ES or not. This paper evaluates the reduction of LSEs' purchasing cost from the electricity market and other LSEs' purchasing cost by introducing ES to customers. It is clarified which kind of customers has the effect of decreasing LSEs' purchasing cost and how much MCP of the whole power system the demand‐side energy storage systems change. Through numerical examples, this paper evaluates the possibility of giving the cost merit to both customers with energy storage systems and LSE by using real data for a year's worth of MCP. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 158(1): 22–35, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20447     

基于三脉波模型的高压直流输电系统直流侧谐波分析及滤波方案设计

对许多高压直流输电工程直流侧谐波的现场测试发现,现场测试的结果与采用传统的六脉波模型计算出的直流侧谐波有很大的差异。因而该文介绍了一种新的模型———三脉波模型,用于分析高压直流输电系统直流侧的谐波。采用三脉波模型分析而得的直流侧的谐波特性完全符合现场测试的结果。该文分析了该三脉波模型的特性,同时给出了基于三脉波模型的直流侧的滤波方案设计。     

多线程技术在幕墙清洗机器人监控系统中的应用

幕墙清洗机器人是在城市现代化进程中产生的新技术,并已成为国内外研究的热点.多任务多线程是Window操作系统的特点之一.本文论证了多线程技术和单线程技术在机器人监控系统中应用的优缺点,肯定了多线程技术在监控系统中的应用,应在擦窗机器人监控系统中加以应用.     

基于转子偏心坐标系的无轴承永磁薄片电机径向悬浮力模型

针对无轴承永磁薄片电机(BPMSM)运行时转子悬浮不够稳定的问题,研究了影响BPMSM转子悬浮性能的主要因素,即转子径向悬浮力模型。依据位移补偿控制理论和角坐标系的概念,建立了新的转子偏心坐标系。在转子偏心坐标系下,基于麦克斯韦应力张量法,利用积分和三角变换推导了转子径向悬浮力模型,并设计悬浮力绕组电流直接控制系统。建立电机的有限元模型,通过对比径向悬浮力的有限元分析结果与数学模型计算结果,验证了所推导数学模型的正确性与准确性。     

浅谈大屏幕系统在电力调度中的应用

以广东电网公司江门供电局调度中心的大屏幕系统为例,介绍大屏幕系统的结构和各种功能,探讨该系统在电力调度中的使用以及与电力调度自动化主站系统的联接等问题,认为大屏幕系统的应用将极大地提高电力调度水平。     

实施需求侧管理对提高发电系统可靠性的影响探究

实施需求侧管理可以提高能源利用率,减少最大负荷需求量,相当于间接增加了系统的发电容量,因此能够提高发电系统的可靠性。简要介绍了发电系统可靠性指标,建立发电系统可靠性分析模型,包括发电容量模型和负荷模型,并分析了非时序蒙特卡洛法在发电系统可靠性评估中的应用。采用模拟法定量,以IEEE可靠性测试系统RTS(Reliability Test System)为例定量分析需求侧管理对发电系统可靠性的影响,分析结果表明实施需求侧管理能够提高能源利用率和发电系统的可靠性,使系统更加安全、经济、可靠地对用户供电。     

航天电磁继电器簧片系统振动特性分析方法的探讨

航天继电器的抗振性是衡量其产品性能和可靠性的重要指标，簧片系统是航天电磁继电器的关键部件。文章通过分析航天电磁继电器簧片系统结构，建立了簧片系统振动特性分析数学模型；根据振动力学分析理论，给出了求解簧片系统振动响应的解析表达式；以某型号航天电磁继电器簧片系统为例，计算并分析了其振动特性，得出了若干对航天继电器设计具有一定指导作用的结论。     

Robust adaptive constrained boundary control for a suspension cable system of a helicopter

In this article, the problems of modeling and controlling are investigated for a suspension cable system of a helicopter with input saturation, system parameter uncertainties, and external disturbances by using the boundary control method. In accordance with the Hamilton's principle, the model of the suspension cable system of a helicopter is established by using a set of partial differential and ordinary differential equations. Considering nonsymmetric saturation constraint, the auxiliary systems are designed to handle with the effect of input saturation. Considering Lyapunov's direct method and the designed auxiliary systems, two robust adaptive boundary controllers are provided by the actuators at the helicopter and the box. Under the proposed controllers, the error between the bottom payload and the target location and the vibration range are uniformly ultimately bounded. Moreover, they will converge to a small neighborhood of zero by selecting the suitable parameters. Meanwhile, to guarantee the validity of the proposed adaptive boundary control laws, some sufficient conditions are raised. Simulation results are provided to verify that the effectiveness of the designed controllers in this paper.     

电网高压在线监测系统供能电源的设计

介绍了一种应用于电网在线监测系统的电源解决方案。通过为取能线圈引入气隙磁阻,提高电源性能,并通过理论计算与软件仿真,实现对取能线圈的结构、铁芯材料、绕组匝数、气隙长度等参数的合理匹配。     

柔性直流配电系统换流器交流侧接地故障的分析

柔性直流配电网中的换流器若经联结变压器接入交流电网,联结变与换流阀之间发生绝缘损坏会产生换流器交流侧接地故障。接地故障对系统运行的影响及其保护方案值得研究。首先分析了柔性直流配电网中各部分的共模等效模型。考虑联结变不同的接地方式,建立了一个典型的五端柔性直流配电系统共模等效电路。推导了各端基频共模电流、电压的计算公式。其次考虑系统可能存在的各种谐振,提出了一种基于换流器直流侧基频共模电流、电压以及功率方向的多端柔性直流配电系统交流侧接地故障的保护方案。最后在PSCAD仿真平台上进行了验证。     

考虑供需双侧响应和碳交易的氢能综合能源系统鲁棒调度

双碳”背景下,为促进可再生能源消纳,约束园区碳排放和应对可再生能源的随机性,构建了含可逆固体氧化物电池(reversible solid oxide cell, RSOC)的园区氢能综合能源系统,并提出考虑供需双侧响应、阶梯碳交易机制和可再生能源出力不确定的鲁棒调度模型。首先,采用RSOC和储氢罐消纳可再生能源富余出力。其次,引入有机朗肯循环(organic Rankine cycle, ORC)余热发电和综合需求响应构成供需双侧响应优化热电运行。然后,通过鲁棒优化理论处理可再生能源的不确定性。接着以系统购能成本、碳交易成本、弃风光惩罚成本和需求响应成本之和最小为目标构建鲁棒调度模型,并采用CPLEX求解。最后通过算例仿真结果验证了模型的有效性。