Experimental study on the Unified Power Flow Controller

This paper presents the results of experimental study on the performance of a Unified Power Flow Controller (UPFC), one of the FACTS (Flexible AC Transmission Systems) controllers. A laboratory‐scale UPFC was manufactured and installed on a laboratory electric power system to investigate its multifunctional capabilities as a power flow controller. The UPFC consists of two 4.5‐kVA, 200‐V back‐to‐back voltage‐sourced converters, labeled “Converter 1” and “Converter 2,” operated from a common DC link provided by a DC storage capacitor of 380 V. It can provide independent control of both the real and reactive power flow in the line. Tests were performed to examine the capabilities of the UPFC, under one‐machine connected to an infinite‐bus system. Steady‐state responses under various kinds of operating conditions were measured and analyzed. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(2): 8– 15, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20538     

西北电网风电与光伏紧急功率控制系统设计

我国已形成新能源基地集群通过特高压直流群外送格局,新能源消纳受直流送电能力和新能源并网功率约束。为提高新能源消纳能力,区别于传统的馈线刚性切除控制,首先分析了利用新能源(风电、光伏)逆变器的快速控制特性,将新能源功率控制纳入电网紧急控制的必要性。新能源功率控制可有效降低冲击,提高控制精细水平,实现有功和无功解耦控制能力。其次针对新能源设备控制、通信现状和有功、无功控制能力,研究将新能源纳入紧急控制的通信时延和可控功率实时感知的技术需求,设计了系统架构,研究了适用场景,并提出了具体的实现方法及相应的控制策略。最后基于实际电网,仿真验证了所提控制架构和控制方法的有效性,其能够有效提高直流送电能力和新能源并网功率。     

考虑广义储能集群参与的配电网协同控制策略

随着需求响应技术的发展,温控负荷、电动汽车等具有灵活调控特性的需求侧资源可作为广义储能参与孤岛配电网的功率波动平抑控制。文章面向空调与电动汽车两类典型的广义储能,提出一种考虑广义储能集群参与的配电网协同控制策略。首先,以负荷聚合商作为控制中心,构建了多元广义储能集群控制架构;其次,分别建立了空调集群与电动汽车集群的广义储能控制模型,在空调群内,计及各空调受控次数的差异,提出改进温度优先序列控制策略,在电动汽车群内,提出了基于荷电状态的功率分配策略;随后,根据空调集群与电动汽车集群的功率响应特性,提出了一种基于低通滤波的多元广义储能协同控制策略;最后,基于Matlab/Simulink的仿真结果验证了所提控制策略的有效性。     

电动汽车复合能源系统设计

为解决燃油汽车带来的环境、能源等负面问题,推进新能源在汽车领域的应用逐渐成为人们关注的焦点。文中基于太阳能电池、超级电容和蓄电池3种能量源,对电动汽车复合能源系统进行了研究。针对各能量源的特性设计了基于Boost电路的最大功率点跟踪控制器以及连接超级电容与直流总线的电流双象限DC/DC变换器,并通过MATLAB仿真工具箱对其进行了仿真,进而确定了电路参数。同时,基于电流约束设计了系统的总体控制策略,并进行了相关测试。实验结果表明,复合能源系统可对太阳能电池进行最大功率点跟踪,而且巧妙融合了超级电容的高比功率以及蓄电池高比能量的特点,有效缩短了蓄电池大电流放电的时间,改善了电动汽车启动及加速时的性能。     

Efficient power regeneration and drive of an induction motor by means of optimal torque derived by the variational method

When the motor speed is reduced by using a regenerative brake, the mechanical energy of rotation is converted to electrical energy. When the regenerative torque is large, the corresponding current increases so that the copper loss also becomes large. On the other hand, the damping effect of rotation increases with time when the regenerative torque is small. In order to use this limited energy effectively, the optimal regenerative torque should be ascertained in order to maximize the regeneration of electrical energy. This paper proposes a methodology, based on the variational method, for the design of regenerative torque for an induction motor in order to maximize the regenerative electric energy. Similarly, the optimal torque for acceleration is derived in order to minimize the driving energy. Finally, an efficient motor drive system with the proposed optimal torque and a power storage system stabilizing the DC link voltage will be proposed. The effectiveness of the proposed methods is illustrated by simulations and experiments. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 173(1): 41–50, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.21010     

能源高质量发展下中国电力供需格局演变趋势

为应对气候变化,世界各国都在加快能源转型,习近平总书记提出了“四个革命、一个合作”能源安全新战略和“碳达峰、碳中和”愿景,要求全力推动能源高质量发展,这将对中国电力供需格局产生深远影响。首先,提炼能源高质量发展的内涵、特征;其次,从消费侧、供给侧、技术、体制等角度研判能源高质量发展下电力行业的转型发展方向;最后,通过构建多区域“能源-经济-电力”分析预测模型体系,从电力需求、电力供应、跨区电力流、电力系统形态、电力市场交易等方面研究中国中长期电力供需格局的演变特征。     

Dynamic modeling of a dual active bridge DC to DC converter with average current control and load‐current feed‐forward

Bidirectional power flow is needed in many power conversion systems like energy storage systems, regeneration systems, power converters for improvement of the power quality and some DC‐DC applications where bidirectional high power conversion and galvanic isolation are required. The dual active bridge (DAB) is an isolated, high voltage ratio DC‐DC converter suitable for high power density and high power applications, being a key interface between renewable energy sources and energy storage devices. This paper is focused on the modeling and control design of a DC‐DC system with battery storage based on a DAB converter with average current mode control of the output current and output voltage control. The dynamic response of the output voltage to load steps is improved by means of an additional load‐current feed‐forward control loop. An analytical study of the load‐current feed‐forward is presented and validated by means of both simulations and experimental results. Copyright © 2014 John Wiley & Sons, Ltd.     

五端口能源路由器控制策略研究

随着可再生能源技术的发展,传统的电力系统无法满足未来供电多样化、能量多向流动的技术要求。为了实现可再生能源的大规模消纳,我国正在积极发展能源互联网。能源互联网的核心装置是基于电力电子技术的能源路由器,能够实现给不同的可再生能源装置和不同负载提供灵活多样化的电气接口,还可实现能量的多向流动和对功率流的管理。文中对应用于中低压交直流电网且结合了储能装置的能源路由器进行了研究。为了满足中低压交直流互联功能与储能功能,所研究能源路由器由模块化多电平变流器(MMC)、双有源全桥变流器(DAB)、低压逆变器与双向储能变流器构成。文中对该能源路由器的控制策略进行了研究,设计了各级控制器的结构与控制器参数,并在各级自身控制策略的基础上,提出了功率前馈控制策略以减小直流端口的电压波动,并进行了仿真验证。     

“十三五”电力发展思路解析

电力是国民经济的重要基础工业,是能源行业的中心。电力健康持续发展事关能源革命、转型升级,事关经济社会发展全局,事关国家安全与国计民生。在简要回顾电力发展历程的基础上,重点剖析了当前电力系统存在的主要问题、矛盾及原因,分析研判了“十三五”及中长期电力发展面临的经济、能源及环境的主要形势和挑战,基于现实、立足矛盾、针对问题、面向未来,提出并阐述了“十三五”时期我国电力工业“绿色清洁发展、协调优化发展、灵活智能发展及市场化发展”的基本思路。     

苏州同里新能源小镇的交/直流混合配电网潮流计算方法研究

苏州同里新能源小镇是一个集光伏发电、风力发电、储能、电动汽车、能源路由器等特征元件为一体的小镇。在传统配电网固有元件(变电站、配电线路、无功补偿、负荷等)的基础上,小镇配电网引入了新型的设备元件(分布式可再生电源、储能设备、电动汽车、直流负荷、能源路由器等),构成了交/直流混合配电网。目前交流配电网的潮流计算方法已经相当成熟,而直流配电网一般都采取闭环运行方式,故该方法无法在交/直流混合配电网中使用。本文根据含能源路由器等新型设备的交/直流配电网特点,将传统的牛顿拉夫逊法进行相应改进,分别对交流配电网和直流配电网进行潮流求解,通过作为接口的电压源换流器,进行交替迭代,直至交/直流网络均潮流收敛。该潮流计算方法将在同里新能源小镇的配电网实例中加以应用。     

Instantaneous active and reactive powers in electrical network theory: A review of some properties

Research into electric power has been on-going since the end of the 19th century. The concepts of instantaneous active and reactive power are the result of the work carried out in the last few decades. In particular, they are used in the optimization of power systems, but they also form part of the general theory of electrical networks.Nevertheless, instantaneous active and reactive powers show noteworthy differences with other electrical powers. Here we review some of their properties and attempt to draw some conclusions that should be taken into account for their correct use. In particular we show the ambiguity of expressions such as “the branches of a network” or “the branches of a multi-terminal network” when these powers are involved.     

考虑风电波动与电动汽车集群储能平抑控制策略

为促进风电在电网中的消纳,减轻配电网负荷压力,提出考虑风电出力波动和电动汽车集群储能系统平抑控制策略.首先,对单体电动汽车入网后行为特性进行储能建模,依据不同荷电状态(SOC)电动汽车有功响应能力,构建电动汽车集群储能模型,基于集群储能能力的差异性,利用多个电动汽车集群协调平抑联络线功率波动.其次,由集群储能系统依据联络线功率平抑波动值进行逐层自适应功率分配,确定各电动汽车蓄电池—超级电容的任务功率,充分利用车网连续调节能力.所提平抑策略可减轻大规模电动汽车连网后配电网中负荷的波动,实现储能系统内部功率相互流动,有效减少常规储能容量配置.     

电动叉车用开关磁阻电机新型集成功率变换器

针对电动叉车用开关磁阻电机（SRM）制动过程中的能量回收问题,研究一种可实现多端口能量灵活转换的新型集成式功率变换器。新型集成式功率变换器采用交错并联双向DC/DC变换器作为传统SRM功率变换器的前端电路,可以在电动及发电模式之间灵活切换。采用超级电容与铅酸蓄电池混合储能,回收减速和下放货物的能量,实现再生制动,并用于加速和举升货物。仿真试验表明所设计新型集成式功率变换器能满足电动叉车频繁起停的要求,并可减小输入输出端的电流波纹,提高能量回收效率。     

A power flow tracing method focused on reactive power and SC

“Tracing the power flow of electricity” is a concept that has become the focus of attention recently, as the deregulation or the liberalization of the electric power market proceeds. Although a number of methods, such as “tracing method by power flow contribution,” have already been published, reactive power contribution has been little studied to date. However, applying “tracing the power flow of electricity” to ancillary service, for example compensation of reactive power, is very important. In this paper, we focus on line flows and static capacitors in particular, and study how to deal with the problem. We perform a computer simulation using a simple system and show the tracing results. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 156(1): 33–43, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/ eej.20118     

An autonomous decentralized control mechanism for power flow in an open electric energy network

This paper discusses a power flow control mechanism for the “open electric energy network” (OEEN), which has been studied by the authors as a demand-side network suitable for a free market of electricity. The important concept of OEEN is that electric energy is treated like a packet of mail, with information about the sender (power producer) and the receiver (consumer). The control mechanism discussed in this paper is called the electric energy router and includes an energy storage device. The electric energy router controls the storage device in such a way that the “electricity packet” reaches a specified consumer from a specified power producer autonomously and in the distributed manner. This paper shows that optimal control theory can be applied to determine the control action of the electric energy router. The obtained optimal control action minimizes the difference between the load pattern of the consumer and the supply pattern of the router under the inequality constraints of energy storage capacity. A numerical example is given in order to check the validity of optimal control theory application. In order to manufacture a small-scale electric energy router for experiments, its basic structure and power control performance are studied through simulation studies. © 1998 Scripta Technica. Electr Eng Jpn, 121(4): 28–37, 1997     

A Two‐Stage Stochastic Mixed‐Integer Programming Approach to the Smart House Scheduling Problem

A “smart house” is a highly energy‐optimized house equipped with photovoltaic (PV) systems, electric battery systems, fuel cell (FC) cogeneration systems, electric vehicles (EVs), and so on. Smart houses are attracting much attention recently because of their enhanced ability to save energy by making full use of renewable energy and by achieving power grid stability despite an increased power draw for installed PV systems. Yet running a smart house's power system, with its multiple power sources and power storages, is no simple task. In this paper, we consider the problem of power scheduling for a smart house with a PV system, an FC cogeneration system, and an EV. We formulate the problem as a mixed‐integer programming problem, and then extend it to a stochastic programming problem involving recourse costs to cope with uncertain electricity demand, heat demand, and PV power generation. Using our method, we seek to achieve the optimal power schedule running at the minimum expected operation cost. We present some results of numerical experiments with data on real‐life demands and PV power generation to show the effectiveness of our method. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 186(4): 48–58, 2014; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22336     

计及需求侧响应的含PET交直流混合系统日前优化调度

近年来,基于清洁能源的分布式发电技术不断发展,风、光为代表的各类分布式电源在配电网的集成水平日渐提升,电力电子变压器由于其强大的端口功率调控特性可实现交流和直流分布式能源的"即插即用".本文建立了计及损耗的电力电子变压器优化调度模型,并综合考虑需求侧可控负荷的响应能力,以运行经济性最优为目标,建立了含电力电子变压器的交...     

电动汽车充电桩直流电能表检定装置的研制

随着电动汽车需求的不断增长,用于电动汽车充电桩直流电能计量的直流电能表大量出现.本文研制的大功率直流电能表设备检定装置针对直流电能表的工作特点设计,选用实时脉冲周期比较法,采用NI公司的数字采集卡PCI-6281作为数据采集,利用LabVIEW(虚拟仪器平台)软件进行数据处理和人机操作界面设计,详解介绍了研制的检定装置...     

风光氢联合式独立发电系统的建模及仿真

提出了一种独立使用的风光氢联合式独立发电系统，该系统由风力发电、太阳能发电、氢能系统(包括电解水制氢、燃料电池系统、超级电容等)及其他系统单元组成。各单元通过2条直流总线联接，并采用功率流控制。由于风力发电与太阳能发电所输出的功率随风速和日照的变化而变化，因此采用燃料电池系统与超级电容堆与风光发电系统配合使用，以保证系统在任何条件下都具有可靠的供电性能。当风能与太阳能充足时，风机与光伏阵列可满足负荷的需要，同时还可向电解池供电；如果不能满足负荷的需要则由燃料电池提供额外的电能，同时由超级电容在短时期内向负荷提供燃料电池最大功率以外的那部分电能。最后在Matlab环境下建立了系统仿真模型，并以西藏边远村落为例对该系统的动态响应进行了仿真分析，仿真结果表明本文提出的供电系统可以用于以西藏为典型代表的风速和光能变化较大的边远地区。     

The Energy Bank-Roadmap for the 21st Century Green power grid

The electric power industry in the U.S. and the world is moving toward predominantly renewable energy. The electrical characteristics of most renewable resources are quite different than traditional generating systems. There is a transition from rotational generating resources to ones that are either static or electrically appear as static. The predominant renewable resources are expected to be wind and solar, where solar resources are expected to dominate due to their favorable economics. Wind and solar resources are non-dispatchable and their power production may not be coincident with demand. Storage resources therefore become an integral component of the 21^st century power grid.This article proposes a new vision, road-map and business model which the author calls the “Energy Bank” toward meeting the Green energy requirements of the electric power industry in the 21^st Century. The Energy Banks are envisioned to be private entities which collect and store energy at their own facilities or contract with private storage facilities within the entire power grid from transmission all the way to distribution and end consumers. This energy is then is made available for withdrawal by the depositor at a different time and location as well as in the form of physical and financial contracts to manage the price risks associated with wholesale markets.In the 21^st Century, similar to money, most of the population make energy, need to store it and like to use it at the different times and locations. The Author argues that Energy Banks as private market forces can facilitate energy transactions among vast number of renewable resources which will be needed by the 21^st Century Electric Power while creating a sustainable business model capable of exerting long-term pressure on the cost of electricity.