超级电容器储能特性研究

基于超级电容器等效电路模型,本文推导了超级电容器等效阻抗函数,研究了恒流充电时的超级电容器的储能基本特性。并结合实验方法,对超级电容器的端电压波动、容量、循环寿命、漏电流进行了广泛测量。在理论分析与实验对比的基础上,根据超级电容器的内部结构探讨了部分特性变化的理论原因,为高效应用超级电容器的储能研究提供了科学依据。     

车用锂离子超级电容的性能实验与建模研究

研究了一种用于深度混合动力车的新型高比能量锂离子超级电容器。对该新型超级电容器在充放电实验平台依照相关标准进行了性能实验。根据实验数据和锂离子超级电容器的基本原理,建立了适用于该新型超级电容器的仿真模型,并在模拟工况下验证了仿真模型的有效性。建立的锂离子混合超级电容器模型具有较高的精度,可用来对该新型超级电容器进行SOC估计和故障诊断,具有较强的工程价值。     

超级电容器组在轨实验系统设计与验证

针对超级电容器组瞬时大功率放电的特点,设计出了一套在轨实验系统,并完成了在轨验证和数据分析。结果表明,实验系统成功地完成了超级电容器组的在轨实验,超级电容器组各项参数稳定,状态良好。超级电容的成功在轨实验为后续产品化及其在武器装备上的应用奠定了基础。     

超级电容器蓄电池混合电源性能研究

超级电容器蓄电池混合电源能充分发挥蓄电池比能量大和超级电容器能快速充放电、循环寿命长的优点,能显著提高电源的峰值输出功率。建立了超级电容器蓄电池混合电源的数学模型,系统地分析了影响超级电容器蓄电池混合电源峰值输出功率的因素,并通过实验对超级电容器蓄电池混合电源的峰值输出功率性能进行了验证。分析和实验结果表明:超级电容器蓄电池混合电源的峰值输出功率与脉动负载的占空比、脉动负载的周期、超级电容器的内阻、蓄电池的内阻、超级电容器的容量、超级电容器的并联支路数有着密切的关系。超级电容器蓄电池混合电源的峰值输出功率比蓄电池有了显著的提高。     

电解电容器的参数性故障辨识方法

针对电解电容器的参数辨识问题,提出了一种基于有限差分法和递推最小二乘法结合的参数辨识方法.首先对电解电容器的故障模型进行了研究,选取电解电容器的电压和电流作为状态参数,应用有限差分法重新建立电解电容器的离散数学模型,然后结合最小二乘递推算法实现电解电容器特征参数的辨识,最后针对buck-boost变换器进行了电解电容器的参数辨识仿真实验,通过与其他辨识方法的实验结果进行比较,验证了该方法具有算法简单,精度高的特点.     

超级电容器的老化趋势分析

超级电容器的老化状态直接影响着储能系统的寿命。通过预测超级电容器性能参数的老化趋势,为系统的控制和管理提供预测性维护信息,将有利于提高系统的可靠性。首先在不同工况下对超级电容器进行了老化实验,并通过阻抗谱分析对其容值和等效串联电阻的变化趋势进行了分析。为了利用有限的实验数据预测超级电容器的老化趋势,提出一种基于支持向量机(SVM)的超级电容器老化预测方法,进一步采用粒子群算法(PSO)优化SVM预测模型的参数,从而完善超级电容器老化趋势的预测模型。结果表明预测值与实验值基本吻合,预测误差小于0.046,验证了基于PSO-SVM的超级电容器老化趋势预测方法的有效性。     

新能源用超级电容器的模型综述

电化学超级电容器简称超级电容器,作为一种新型的储能装置,在电力系统中具有广阔的应用前景。建立一个能精确反映实际工作特性的模型,对于超级电容器的合理使用、性能优化和系统仿真具有重要的研究意义。本文介绍了超级电容器的基本工作原理,综述了现有的各种超级电容器模型,详细分析了各种模型的特点和适用范围,针对在工程中应用最多的等效电路模型进行了实验验证,并对实验结果和模型结构进行了深入探讨。通过分析超级电容器建模研究现状和存在的不足,展望了超级电容器建模研究的发展趋势和研究重点。     

电化学超级电容器建模研究现状与展望

电化学超级电容器简称超级电容器,作为一种新型的储能装置在电力系统中具有广阔的应用前景。建立一个能精确反映实际工作特性的模型对于超级电容器的合理使用、性能优化和系统仿真具有重要的研究意义。本文介绍了超级电容器的基本工作原理,综述了现有的各种超级电容器模型,详细分析了各种模型的特点和适用范围,针对在工程中应用最多的等效电路模型进行了实验验证,并对实验结果和模型结构进行了深入探讨,通过分析超级电容器建模研究现状和存在的不足,展望了超级电容器建模研究的发展趋势和研究重点。     

电容器干燥处理过程中心子温度分布的研究

为了了解在干燥处理过程中电容器的内部温度分布,为改进电容器的干燥处理工艺提供实验和理论依据。本文通过实验的方法着重比较了在圆罐或方罐内进行干燥处理过程中电容器的内部温度分布,以及电容器采用立放或卧放方式时干燥处理过程中电容器的内部温度分布,可以看出电容器干燥处理时采用卧放方式具有一定优势。在采用圆罐或方罐干燥处理时由于罐体结构以及加热方式的差异,电容器内部温度分布也有差异。通过本次研究可以看出,应该改进现有电容器干燥处理工艺,使电容器在干燥处理过程中内部的温度分布更加均匀。从而提高电容器干燥处理效果,提升电容器的电气性能。     

膜纸复合介质并联电容器的可靠性

本文从纸介质浸渍矿物油高压并联电容器的弱点,阐述膜纸复合介质并联电容器的优越性能,指出膜纸复合介质并联电容器击穿损坏的主要因素,决定于电容器的过电压及其低温性能,并以充分的实验数据,阐述膜纸复合介质并联电容器运行的可靠性,尤其在电容器部装设内熔丝能有效地防止电容器的早期损坏,极大地避免了电容器外壳爆破的危险,从而提高了电容器的运行可靠性。     

基于Camera Link的线阵CCD外同步控制设计与实现

在纺织布匹疵点检测系统中,获取平稳清晰图像对后续布匹图像疵点的精确检测和类别正确识别至关重要。由于布匹疵点检测系统外部事件的不可预测性,如何控制线阵CCD以获取平稳清晰的图像。针对这一问题提出了一种线阵CCD相机外同步控制方法。该方法采用VHDL语言在Xilinx公司Virtex-II PRO FPGA架构上设计实现。重点介绍了相机自适应的外同步控制设计方案和实现方法,通过ModelSim仿真和布匹疵点检测系统的在线测试,验证了该方法的有效性和可行性。     

Primary and secondary frequency regulation in a longitudinal hydrothermal system by Liapunov method

The problem of primary and secondary frequency regulation of a multi-machine power system is analysed with a Liapunov function method based on a quadratic performance index. The main purpose is to determine the best set of parameters of primary and secondary regulation according to an optimisation criterion. The objective consists of achieving a settling time as short as possible which is relevant in a longitudinal system, whose structure includes long transmission lines with a reduced number of loops.     

具有特殊地形条件的长距离供水工程水锤防护

在长距离供水工程中输水管道一般按地形走势布置。针对一些地形条件特殊的供水工程,本文提出了一种空气罐与出口溢流池联合设置的水锤防护方案,并建立了出口溢流池的数学模型。在空气罐体型一定时,给出了出口溢流池截面积的理论计算公式,有效地减小了在溢流池体型初期选取过程中的盲目性和工作量。结合某长距离输水工程,对比分析了空气罐和出口溢流池联合防护与单纯的空气罐防护对水锤的影响。结果表明空气罐与出口溢流池联合防护方案在前陡后缓的长距离供水工程中能够取得良好的水锤防护效果,且溢流池的溢流水位越高,其对负压的防护效果越好。     

基于遗传算法(GA)的配网无功优化控制的两部算法

提出了基于遗传算法的两部算法,该算法经用Ｃ＋＋语言编程后,分别在１６节点和４４节点算例系统上测试,结果表明两部算法比单纯用遗传算法可以在更短的计算时间内获得更好的解。     

Numerical Investigation of a Molecular Switch Based on Conformational Change, with the Inclusion of Contacts

We discuss the possibility of implementing a switch based on a conformational change, consisting in a relative rotation of a molecule containing two benzene rings, functionalized with proper substituents. Contacts are simulated with three-atom gold clusters, which are connected to the rest of the molecule via a thiol group. Relative rotation of the two rings, induced by a transverse electric field, determines a variation of the height of the potential barrier separating them, due to the change in the amount of conjugation of the π orbitals. The action of such a barrier is evaluated by computing the shift of the electron density as a function of a longitudinal electric field.     

Performance Comparison of Circuits for Pole‐Mounted STATCOM Using SiC Devices

The recent years have seen an increasing trend in the cumulative installed capacity of distributed generators. As a result, voltage management may become difficult in existing power distribution systems in the future. A STATCOM (STAtic synchronous COMpensator) is a promising option for solving this problem because it can control reactive power rapidly and continuously. For a distribution system, STATCOM needs to be pole‐mounted to realize its low cost. However, a transformer for a STATCOM is large and heavy, and hence it is difficult to install a STATCOM on a distribution pole. We adopt a transformerless STATCOM to reduce STATCOM size and use SiC devices with low‐loss performance to obtain a more compact and efficient STATCOM. There are a large number of circuits available for a STATCOM, and there has been considerable research on performance comparisons among these circuits. However, these comparisons were drawn under different conditions, including switching frequency and level number for the circuits. In addition, these comparisons do not include the use of SiC devices. We made an equitable comparison for a 100 kVa pole‐mounted STATCOM using SiC devices. We discuss the performance and characteristics of each circuit in terms of efficiency and volume.     

新型制冷剂研究及应用冰箱压缩机的设计

为了解决R12的主流替代工质R134a作为冰箱制冷剂时存在的问题,提出给R134a系统加入R600a组成混合工质R134a/R600a的方案,提供物性和热力性能比较结果,证明R134a/R600a作为冰箱制冷剂比R134a和R600a更具有优势,并提出了采用新型制冷剂的冰箱压缩机的改进方案.R134a/R600a的性能试验结果证明其与矿物油的互溶性良好,成功的解决了R134a系统由于更换润滑油而产生的一系列问题.     

Periodic steady-state solution of a synchronous generator based on a voltage-behind-reactance formulation and the Poincaré map method

A powerful blend based on a voltage-behind-reactance (VBR) model and the Poincaré map method, suitable to carry-out harmonic oriented analyses, is presented in this paper to compute the periodic steady-state solution of a synchronous generator. The VBR model, as originally conceived, is modified and instead a per-unit version, tailored to the acceleration procedure, is used. The acceleration of the convergence to the periodic steady-state is accomplished with a Newton method and the Poincaré map. A Numerical Differentiation approach allows the computation of the transition matrix involved in the acceleration procedure using a sequential perturbation of the state variables. The periodic steady-state solution of synchronous generators is reported for a set of operating conditions such as change of load, a three-phase fault and a single-phase fault. Furthermore, the harmonic analysis of a system comprising a RLC circuit with a varying degree of unbalance, fed from a synchronous generator is carried-out with the acceleration procedure. Important speedup factors up to 145 are reported for large turbine generators. The application of a Newton based acceleration procedure to a VBR synchronous machine model yields important benefits for the efficient computation of periodic steady-state solutions and it is particularly useful for test cases involving large rotary machines with an inherently large inertia.     

Single transistor high linearity and wide dynamic range active inductor

In this paper, an active inductor (AI) with high linearity and high dynamic range, including a minimum number of components, is presented. The AI is composed by a single transistor, and by a passive compensation network; the latter allows the control of the values of both the inductance and the series resistance. In order to show the feasibility of the proposed AI for filter applications, a prototype board on a TLX8 substrate with a first‐order active band‐pass filter has been fabricated and tested. The filter has a center frequency of 2470 MHz (useful for Bluetooth applications) and a measured noise figure (NF) of 9 dB with a ?5 dBm P₁dB compression point, and a 75 dB dynamic range. Copyright © 2013 John Wiley & Sons, Ltd.