光伏发电系统中逆变器技术应用及展望

光伏阵列产生的是直流电流和电压,而许多负载都使用交流电,因此需要通过逆变器把直流电变成交流电。随着光伏发电系统(Photo Voltaic System,简称PVS)的日益推广,太阳能PVS中使用的逆变器也越来越多。如何用户对深入了解PVS中的逆变器性能及正确选用逆变器也越来越重要了。本文分类总结了用于PVS中的逆变器;分析研究了这些逆变器在PVS系统中的应用特点;展望了PVS中逆变器向高性能和智能化方向发展的趋势。     

太阳能光伏发电发展情况

“2 0 0 4年中国国际可再生能源设备与技术展览会国际研讨会”于4月7～1 0日在京召开。会上交流了太阳能光伏发电的发展情况。太阳能光伏发电是太阳能利用的重要方式,也是我国重点提倡开发利用的绿色能源。特别是我国西部地区、人口分散、经济落后,无电户很多,而太阳能利用条件却得天独厚,随着国家西部开发政策的推行及“光明工程”的实施,太阳能光伏发电技术取得了较快发展。目前我国光伏发电市场需求旺盛,光伏电池销售量平均增长率在30 %以上,近几年年销售量均保持在2 .5 MW左右。2 0 0 0年光伏产品保有量已达到1 5 MW。主要应用于通信…     

分布式光伏发电系统接入电网的设计要求分析

正2012年10月26日,国家电网公司发布《关于做好分布式光伏发电并网服务工作的意见(暂行)》,在此基础上扩充电源种类,将并网服务扩大到所有类型分布式电源。2013年2月27日,公布《关于做好分布式电源并网服务工作的意见》,从3月1日起,普通用户在利用太阳能、风能等新能源发电自给自足的同时,实现余电上网。之后,国家电网公司进一步出台了《国家电网公司关于印发分布     

太阳能光伏发电技术(6)光伏发电系统的逆变器

逆变器与整流器恰好相反,它的功能是将直流电转换为交流电。这种对应于整流的逆向过程,称之为“逆变”。太阳电池在阳光照射下产生直流电,然而以直流电形式供电的系统有很大的局限性。例如：日光灯、电视机、电冰箱、电风扇等均不能直接用直流电源供电,绝大多数动力机械也是如此。此外。当供电系统需要升高电压或降低电压时,交流系统只需加一个变压器即可．而在直流系统中升、降电压的技术就要复杂得多了。因此,除单纯直流负载用户外,在离网供电系统中大都需要配备逆变器。逆变器还具有自动调压或手动调压功能,可改善光伏发电系统的供电质量。     

光伏发电系统自动监测与控制

对并网光伏发电系统的自动监测和控制进行了设计和研究。并网光伏发电系统中太阳电池阵列产生的直流电通过光伏并网逆变器转换为与大电网相同相位与频率的220 V或380 V正弦交流电,然后并入大电网。分布式光伏发电系统组成的微网和大电网双向交换,通过大电网调节并网光伏发电系统不足和多余的电力,使系统可靠地输出稳定、波形良好的正弦交流电。     

基于Android的光伏发电系统研究

以小型光伏发电为例,从光伏发电系统开始展开研究,结合基于Android的移动手机客户端提出一套实时性的控制管理系统。该系统通过基于ARM的嵌入式系统实现了现场数据的采集,并且利用ARM的串口通信功能设计了基于Android的移动管理终端软件。经过试验验证,该系统可有效地提高系统效率,具有一定的市场推广价值。     

配电网中的分布式光伏系统发电性能仿真

针对基于配电网的分布式光伏发电系统发电性能开展仿真研究.分析了分布式光伏发电系统拓扑结构,根据光伏系统关键部件运行机理,建立了光伏组件、光伏逆变器运行模型,根据光伏组件I-V特性,建立光伏组件阴影遮挡模型.结合现场实际测试,确定光伏系统各环节运行模型参数,通过分布式光伏系统各环节结构以及光伏部件,对分布式光伏系统发电性...     

并网型光伏发电系统控制技术研究

随着全球石油、煤炭等矿产资源的日益减少,人们对太阳能这一取之不尽用之不竭的清洁能源的利用越来越重视。以传统的独立太阳能光伏发电技术为基础,研究和设计了并网型太阳光伏发电控制系统。     

太阳能光伏发电技术(12)光伏发电技术应用实例

1独立光伏发电系统 独立光伏发电系统指采用光伏组件方阵为主要供电电源的,通过独立小电网为居住相对集中的用户群供电的系统．通常的供电半径不超过1公里,以保证末端用户的供电电压。这样的系统一般用于解决偏远山区、沿海的村落供电问题。独立光伏发电系统主要由光伏组件方阵、充电控制器、逆变器、蓄电池组、交流配电柜和低压电网组成。根据当地的资源条件,有时也以风力发电机组、柴油发电机组辅助以提高供电保障率,降低运行成本。独立光伏发电系统以其供电稳定可靠,安装方便,操作、维护简单等特点,已得到越来越广泛的应用,是常规电力的一种补充和替代。我国政府组织实施的“送电到乡”工程,德国政府援助的西部光伏村落项目等都采用这种系统技术。在我国的西藏、青海、新疆、内蒙古、四川、云南、甘肃等省（区）总共有大约1000个独立光伏电站在运行,最大的光伏独立电站在新疆．装机容量145kW。独立光伏系统在我国无线通讯基站和边远铁路信号系统中被大量应用。     

内蒙古首家太阳能光伏发电预报系统建成

2011—12—13,“鄂尔多斯伊泰太阳能光伏发电预报系统”完成建设,并投入业务试运行。该系统由鄂尔多斯市气象局、内蒙古自治区气象局气候中心、湖北省气象局气象科技服务中心、伊泰太阳能光伏电站等多家单位共同参与研发,基于中尺度数值天气预报模式、采用原理法和动力一统计法实现了预报光伏电站未来3d逐小时光伏发电量（功率）及太阳辐射量的功能。系统由资料采集处理子系统、数据库子系统、预报产品制作子系统和预报产品Web发布子系统组成。该预报系统的建成,将成为气象科技转化为生产力的典范。。     

Ways to calculate electric fields in traction electric motor insulation by equivalent charge method

A procedure permitting one to calculate the electric fields in multilayer insulation based on the equivalent charge method is presented. Consideration of the new algorithm shows its fast response and proper accuracy.     

基于Pockels效应的大气电场测量研究

为解决常用场磨式大气电场仪体积大、机械磨损严重、易受电磁干扰、测量带宽窄等问题,在研究分析Pockels效应原理的基础上,提出应用Pockels效应来测量大气电场的方法。对晶体、光源的选择及传感器设计中出现的问题进行了分析,设计了一种基于Pockels效应原理的脉冲电场传感器,该传感系统包括稳定高效的光源、Pockels晶体探头、数据采集及处理电路。通过模拟仿真,说明了这种测量方法是可行的,为进一步研制大气电场测量传感器,提高其性能提供了理论依据。     

Development of three-dimensional electric field computation system by surface charge method

This paper describes development of three-dimensional electric field computation system by surface charge method. Using this system, both potential and electric field in the case which includes resistance or true electric charge can be calculated. And this system is able to be connected to the pre-post processors, which is useful for us to make arbitrary shape and to display results of analysis.     

Evaluation method of computational error for electric field analysis by a surface charge method

In this paper, an evaluation method of computational error for the electric field analysis by a surface charge method is proposed. In the method, an approximate equation of the smoothness of the electric field distribution is used to evaluate the computational error. In two‐dimensional and axisymmetric problems, the approximate equation of the smoothness is expressed by the second derivative form of the surface charge density with respect to the distance along the surface. Furthermore, the smoothness is expanded to three‐dimensional problems and a general form of the equation for the smoothness is obtained. The applicability of the proposed method is verified by computation results of a two‐sphere model and a hyperboloid model. © 1998 Scripta Technica, Electr Eng Jpn, 126(1): 7–14, 1999     

Development of three-dimensional electric field analysis by segment arrangement based on a charge simulation method

This paper describes the development of three-dimensional electric field analysis by using the so-called segment method which enables the electric field to be calculated with high accuracy and with enhanced efficiency, for high-voltage apparatus. In the segment method, electrode configuration of high-voltage apparatus is simulated by small components which are called segments and by the arrangement of several kinds of such segments. In this calculation, the charge simulation method is used which is suitable for segment application. As basic segments, spherical, cylindrical and ring segments are used and in addition to these, as subsegments, disc and elbow segments are adopted for good simulation of the total electrode configuration. In this paper, the fundamental construction and arrangement parameter of segments were discussed. Moreover, the segment method was applied to an actual high-voltage apparatus and the calculation accuracy was discussed. It was clarified that the segment method has sufficient calculation accuracy and is a very efficient means for three-dimensional electric field analysis.     

Electric field calculation in composite dielectrics by surface charge method based on electric flux continuity condition

We propose a new surface charge method based on the continuity of electric flux passing through each partial area on the dielectric boundary. N partial areas divided on the boundary give the boundary equations for solving N unknown variables representing the surface charge density distribution. The electric flux is numerically calculated by integrating the normal component of electric flux density on each partial area. This method permits us to exclude the singularity of edge parts from the boundary equations because these parts do not contribute to the integration area. In this paper, we apply first‐order functions to simulate both triangular surface shape and charge density distribution on its surface as well. First, we have computed the electric field for a spherical dielectric under a uniform field. The calculated results show that the accuracy of the electric field at the spherical center is almost equal to the accuracy of the total surface area of the polygon which represents the sphere. Furthermore, this method has improved the accuracy of the field by about one order compared with the conventional surface charge methods. Second, we have computed the electric field for a dielectric human model under a uniform field. The calculated results demonstrates that the proposed method works well for a complicated shaped object with a dielectric constant greatly different from that of an ambient medium. © 2002 Scripta Technica, Electr Eng Jpn, 138(4): 10–17, 2002; DOI 10.1002/eej.1133     

基于等效磁荷法的永磁电机Halbach阵列磁极磁场分析

基于等效磁荷法推导出永磁电机转子磁极——瓦形磁体在空间的磁场分布。同时用有限元法进行了分析,表明两者之间偏差较小,等效磁荷法满足计算精度要求。进而利用该方法建立了永磁电机的Halbach分布转子磁极静态磁场的模型,通过改变影响转子磁极磁场分布的极弧比和副磁极磁化角度两个因素,得到在不同磁极结构下的转子磁极静态磁场径向分量变化规律:每一极中主磁极空间跨度变大会导致Halbach永磁电机转子磁极静态磁场的径向分量基波幅值变大,而谐波含量先减小后增大;随着副磁极磁化角度变大,转子静态磁场的基波幅值先变大后减小,而谐波含量刚好相反,先减小后变大。     

基于模拟电荷法的变电站工频电场仿真分析

随着供电需求的增大,超高压变电站越来越接近公众活动区域,变电站站内的电场分布情况也显得越来越重要。本文提出改进的模拟电荷法,推导了带电体周围的工频电场计算公式。通过对500k V变电站进行模型建立及简化,编程计算出站内离地1.5m处的工频电场强度;采用CDEGS软件对重庆某500k V变电站进行仿真计算,将仿真结果和实测值与本文算法的计算结果进行对比,验证了本文算法的正确性与有效性。最后选取该变电站内三条路径,计算分析该处工频电场强度的分布情况,为深入研究变电站的工频电场分布提供参考。     

Analysis of atmospheric electric field variation signals using digital natural observation method

As the atmospheric electric field always fluctuates, its observed waveforms are very complicated. It is important to detect the characteristic variation from the observed signals and determine its cause. The natural observation method is adequate for analyzing such nonperiodic signals as the atmospheric electric field signals. In this method the aspectum is proposed as the quantity to estimate the instantaneous power. In this study signal processing by the aspectum was applied to signals of atmospheric electric field variation. It was clarified that a strong correlation exists between the instantaneous fluctuations of atmospheric electric field and the wind speed in the convenient meteorological environment. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 155(1): 27–34, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20302     

基于表面电荷法的输电线路表面电场强度计算

三相输电线路导线表面电荷的分布是不均匀的,各点电场强度的大小也不同.文中采用表面电荷法计算导线表面的电荷密度,然后求出导线表面各点的最大电场强度值.计算方法能够反映出电荷密度及电场强度沿导线圆周分布的情况,根据计算结果优化高压输电线路的布置.