共查询到20条相似文献，搜索用时 15 毫秒
1.
为提高动态电压恢复器(Dynamic Voltage Restorer,DVR)补偿电压的输出精度,在计算分析DVR数学模型的基础上,对DVR开环控制和PD闭环控制进行仿真,并利用MATLAB软件仿真验证了两种控制方式下不同补偿策略的补偿效果。结果表明,PD闭环控制可有效补偿电压凹陷,改善系统的动态补偿特性。 相似文献
2.
电压陷落(电压骤降)是电能质量的重要问题,也是电力工程领域的一个重要研究方向。电压陷落不仅会引起电力系统的安全和电能质量问题,也会危及用电设备的可靠运行。为了解决这个问题,该文提出了一种新型动态电压补偿器的设计,它并无注入变压器,直接串联在低压线路中、保护用电设备。该设计主要解决90%以上的电压陷落,它充分利用电压陷落时电网所剩的电压,达到用最少量的直流电容量来储能的目的。 相似文献
3.
配电系统的结构对用户遭受电压暂降有很大影响,通过规划使系统具备多电源供电方式、母线分段并增设电抗器或装设快速备用电源等,则可有效降低电压暂降问题的严重性,确保重要负荷获得高质量的电能.本文主要针对供电网络结构的设计、供电方式以及参数与电压暂降缓解的关系进行讨论. 相似文献
4.
吴德明 《重庆职业技术学院学报》2006,15(1):46-47
电子镇流器是集点燃与限流为一体的电子装置。建立气体放电灯不加功率因数补偿,荧光灯电子镇流器串联电压谐振的数学模型。采用串联电压谐振产生高压起辉,必须采取过流保护措施。电子镇流器高次谐波的产生及其所带来的危害。 相似文献
5.
Grid-connected inverter for wind power generation system 总被引：3，自引：0，他引：3
In wind power generation system the grid-connected inverter is an important section for energy conversion and transmission, of which the performance has a direct influence on the entire wind power generation system. The mathematical model of the grid-connected inverter is deduced firstly. Then, the space vector pulse width modulation (SVPWM) is analyzed. The power factor can be controlled close to unity, leading or lagging, which is realized based on PI-type current controller and grid voltage vector-oriented control. The control strategy is verified by the simulation and experimental results with a good sinusoidal current, a small harmonic component and a fast dynamic response. 相似文献
6.
顾影 《淮南职业技术学院学报》2003,3(2):70-73
淮南矿业集团公司电力公司电力调度系统潮流图克服了原有电力调度系统一大缺陷,利用画图软件(MG)经过自行设计,结合数据库编制而成。这其中经过界面设计、图元生成、数学模型建立(数据库中)、文件关联等诸道程序,最后调试而成。它能直观地反映电力网络上的电流、功率的流向和分布,全面、实时地反映出电力网络上主供电源端与用户端的负荷供应及负荷分配情况,及时、方便地调整峰、腰、谷负荷,有利于提高发电机组运行效率,提高电力网络系统功率因素。使原有电力调度系统的调度功能更加强大。 相似文献
7.
新能源光伏发电并网系统中的逆变器、非线性负载以及变压器等器件产生的谐波,会影响电能质量和安全。为了抑制系统中的谐波,使输出电流很好地跟踪并网电压,实现输出电流的稳定性,提出一种带锁相环和电压反馈双电流环的LCL型光伏并网逆变器谐波抑制方法。对逆变器控制系统进行分析,建立数学模型,通过MATLAB/Simulink搭建仿真系统。仿真结果证明:该方法可以有效抑制谐波,提高电能的供电质量,满足新能源光伏并网系统对电流谐波畸变率的要求。 相似文献
8.
Equivalent circuit model-based state-of-charge (SOC) estimation has been widely studied for power lithium-ion batteries. An appropriate relaxation period to measure the open-circuit voltage (OCV) should be investigated to both ensure good SOC estimation accuracy and improve OCV test efficiency. Based on a battery circuit model, an SOC estimator in the combination of recursive least squares (RLS) and the extended Kalman filter is used to mitigate the error voltage between the measurement and real values of the battery OCV. To reduce the iterative computation complexity, a two-stage RLS approach is developed to identify the model parameters, the battery circuit of which is divided into two simple circuits. Then, the measurement values of the OCV at varying relaxation periods and three temperatures are sampled to establish the relationships between SOC and OCV for the developed SOC estimator. Lastly, dynamic stress test and federal test procedure drive cycles are used to validate the model-based SOC estimation method. Results show that the relationships between SOC and OCV at a short relaxation time, such as 5 min, can also drive the SOC estimator to produce a good performance. 相似文献
9.
动态电压恢复器（DVR）良好的动态性能和很高的性价比使得它成为治理电压凹陷的最经济、有效的手段。文章就目前国内外有关DVR研究的现状从动态电压恢复器的储能方式、补偿与控制策略的研究和电压暂降的检测方法这三方面进行了详细的阐述和分析,最后总结并讨论了DVR的发展趋势。 相似文献
10.
基于dq0变换的电压暂降检测方法研究 总被引：1，自引：0，他引：1
包晓晖 《宁波职业技术学院学报》2008,(5):27-29
提出了一种基于dqO变换的可用于三相不平衡电压暂降检测的方法。介绍了电压暂降及dqO变换的概念,分析了利用dqO变换后得到的ua,uq,u0分量特征值来辨识不同情况下的电压暂降信号,最后给出控制检测的算法和原理框图。 相似文献
11.
This paper presented a control design methodology for a proton exchange membrane fuel cell （PEMFC） generation system for residential applications. The dynamic behavior of the generation system is complex in such applications. A compre- hensive control design is very important for achieving a steady system operation and efficiency. The control strategy for a 60 kW generation system was proposed and tested based on the system dynamic model. A two-variable single neuron proportional-integral （PI） decoupling controller was developed for anode pressure and humidity by adjusting the hydrogen flow and water injection. A similar controller was developed for cathode pressure and humidity by adjusting the exhaust flow and water injection. The desired oxygen excess ratio was kept by a feedback controller based on the load current. An optimal seeking con- troller was used to trace the unique optimal power point. Two negative feedback controllers were used to provide AC power and a suitable voltage for residential loads by a power conditioning unit. Control simulation tests showed that 60 kW PEMFC generation system responded well for computer-simulated step changes in the load power demand. This control methodology for a 60 kW PEMFC generation system would be a competitive solution for system level designs such as parameter design, performance analysis, and online optimization. 相似文献
12.
Power Quality （PQ） combined disturbances become common along with ubiquity of voltage flickers and harmonics. This paper presents a novel approach to classify the different patterns of PQ combined disturbances. The classification system consists of two parts, namely the feature extraction and the automatic recognition. In the feature extraction stage, Phase Space Reconstruction （PSR）, a time series analysis tool, is utilized to construct disturbance signal trajectories. For these trajectories, several indices are proposed to form the feature vectors. Support Vector Machines （SVMs） are then implemented to recognize the different patterns and to evaluate the efficiencies. The types of disturbances discussed include a combination of short-term disturbances （voltage sags, swells） and long-term disturbances （flickers, harmonics）, as well as their homologous single ones. The feasibilities of the proposed approach are verified by simulation with thousands of PQ events. Comparison studies based on Wavelet Transform （WT） and Artificial Neural Network （ANN） are also reported to show its advantages. 相似文献
13.
Modeling of D-STATCOM in distribution systems load flow 总被引：1，自引：0，他引：1
HOSSEINI Mehdi SHAYANFAR Heidar Ali FOTUHI-FIRUZABAD Mahmud 《浙江大学学报(A卷英文版)》2007,8(10):1532-1542
This paper presents modeling of Distribution STATCOM (D-STATCOM) in load flow calculations for the steady- state voltage compensation. An accurate model for D-STATCOM is derived to use in load flow calculations. The rating of this device as well as the direction of required reactive power injection for voltage compensation in the desired value (1 p.u.) is de- rived and discussed analytically and mathematically by the phasor diagram method. Furthermore, an efficient method for node and line identification used in load flow calculations is presented. The validity of the proposed model is examined by using two standard distribution systems consisting of 33 and 69 nodes, respectively. The best location of D-STATCOM for under voltage problem mitigation approach in the distribution networks is determined. The results validate the proposed model for D- STATCOM in large distribution systems. 相似文献
14.
引入开关函数的概念,考虑了统一潮流控制器(UPFC)各相桥臂电力电子器件具体的开关状态以及三相电网电压的不平衡因素,建立了可反映UPFC装置内部开关特性和运行机理的UPFC暂态数学模型.该模型能够反映UPFC最终的输入控制量及输出量,并合理地设计了应用于该模型的电压空间矢量脉宽调制(SVPWM)控制方案. 相似文献
15.
丁莲环 《宁德师专学报(自然科学版)》2003,15(3):280-284
等电位联接是建筑物防雷、防漏电及低压配电系统防止电气事故的重要措施之一,通过对TN系统的分析,证明采用等电位联接可大幅度降低故障状态下的接触电压,应在建筑供电设计及低压配电系统中广泛采用。 相似文献
16.
本文首先基于三相静止坐标系的典型控制方案与基于d-q同步旋转坐标系的矢量控制方案作了比较,然后运用功率平衡的原理对本文给出的矢量控制方案进行了系统设计,并在此基础上提出一种前馈控制策略并进行了仿真验证。 相似文献
17.
面向用户的精品课程教学信息资源整合模式研究 总被引：1，自引：1，他引：0
分析当前精品课程教学信息资源(主要指课程网站资源)共享模式的基础上,针对精品课程教学信息资源共享所面临的一系列问题,结合江苏省精品课程教学资源数据库的建设,提出了面向用户的精品课程教学信息资源整合方案——中心(区域性)资源整合模式,实现了课程资源的规范组织、集中存储、统一服务,并在此模式基础上建立了应用系统。 相似文献
18.
钟宇明 《深圳职业技术学院学报》2012,11(3):13-17
与经典的PID控制器不同,模糊控制不需要获取系统精确的数学模型．根据系统的要求,设计模糊控制器,以给定参考电压与实际电压之间的偏差及其微分作为输入,通过合理的推理规则,得到占空比输出,去控制开关管的开关时间．论述了模糊控制器的详细设计过程,以及在MATLAB中建立仿真模型的过程．仿真结果表明系统具有较好的稳态和动态性能． 相似文献
19.
要实现“陈省身猜想”,必须要弘扬科学精神,从数学的创新入手,形成“中国数学学派”。“陈省身猜想”的意义是多方面的,它有着强有力的感召力,激励着中国的数学研究者大胆创新,为早日把中国建成世界数学强国而努力奋斗。 相似文献
20.
Modelling and control PEMFC using fuzzy neural networks 总被引：1，自引：0，他引：1
INTRODUCTION With worldwide increase of air pollution and the environmental consciousness of governments,people have to look for new resources to mitigate the energy crisis and improve the present environmental status(Baschuk and Li,2000;Rowe and Li,2001).Fuel cells are highly efficient and environmentally clean electricity generators(Berning et al.,2002)that convert the chemical energy of a gaseous fuel directly into electrical energy and play an important role in solving the energy pro… 相似文献