面向智能配电网可信量测装置高储能密度的电力电容器介质Bi_(1.5)ZnNb_(1.5)O_7(BZN)薄膜材料制备

随着配电网向着可靠性、稳定性、安全性和交互性方向的发展,其对电力电容器的储能性能提出了更高的要求。为制备高储能密度的电力电容器用介质材料,利用磁控溅射技术在Pt-Si基底上制备Bi_(1.5)ZnNb_(1.5)O_7(BZN)薄膜,通过在氧气氛中进行后退火处理,有效地提高了BZN薄膜的结晶性能,并对不同退火条件下BZN薄膜的介电常数、介质损耗因数、漏电流密度、击穿场强和储能密度进行测试分析,表明:氧气氛退火处理能提高BZN薄膜的电学性能,当在10 000 Pa以上的氧气压下退火后,BZN薄膜的储能密度达到9.0 J/cm~3左右,提高到未经过退火BZN薄膜的4.5倍。     

高储能密度全有机复合薄膜介质材料的研究

电容器储能以其轻便、高效、环保等特点正在逐步引起人们的重视。为制备高储能密度的电容器介质材料,研究以聚偏氟乙烯(PVDF)为基体,以纳米尺度的导电聚苯胺(PANI)为填料,采用溶液法及后续的球磨工艺制备了高储能密度的全有机复合薄膜介质材料。研究了添加物含量、频率等因素对复合介质材料介电性能的影响。发现当PANI体积分数达到0.05时(略高于渗流阈值fC=0.041),复合薄膜的介电常数在100 Hz条件下高达456,击穿场强为60 MV/m,储能密度达到了7.2 J/cm3,与PVDF基体相比提高了3倍多。另外还发现即使在渗流阈值附近,复合薄膜介电性能仍具有一定的频率稳定性。介电常数在低频范围(102~104Hz)内基本保持不变。利用SEM对复合薄膜的表面形貌进行了分析,发现有机填料PANI粒子在PVDF基体内有很好的分散性。另外利用XRD分析了复合薄膜的晶体结构,发现该制备工艺条件下所得复合材料基体主要以β-PVDF形式存在,这有助于发挥PVDF基体的功能性。渗流阈值理论可用来解释介电常数随添加物含量和频率的变化规律。研究结果表明,该制备工艺可得到适用于较宽频率范围的高储能密度复合薄膜。     

电力电容器用高储能密度介质材料的研究

随着电子、信息和电力工业的快速发展,高储能密度介质材料受到了越来越多的关注。为制备高储能密度的电容器用介质材料,研究以溶剂共混法(DMF作为溶剂)获得Al/BT/PVDF和Ag/BT/PVDF三元复合材料,并对制成的三元复合材料的相对介电常数、击穿场强和储能密度进行测试分析,测试结果表明:复合材料的介电常数与混入金属前相比变化不大;当铝含量为2.0%,BT含量为7.5%时,复合材料储能密度达到了2.0 J/cm~3,提高到纯PVDF的5倍。     

聚偏氟乙烯基金属化膜电容器自愈特性的研究

聚偏氟乙烯基聚合物是开发高储能密度金属化膜电容器的重要介质之一,而对其自愈特性的研究是提升储能特性的关键。通过对聚偏氟乙烯/聚甲基丙烯酸甲酯共混(PVDF/PMMA)薄膜与金属化膜电容器心子的耐压试验、自愈点形貌表征与自愈能量等效电路计算,与聚丙烯电容心子对比分析了电容器的击穿场强、自愈能量等特性。发现批量化制薄膜的击穿场强相比实验室制薄膜降低约21%;电容心子贯穿性击穿场强为薄膜击穿场强的54%,心子平均自愈面积大于同等容量聚丙烯心子。在此基础上建立了自愈过程等效电路模型,讨论了PVDF/PMMA电容心子自愈机理。     

本征耐高温电极化储能聚合物电介质研究进展

具有高能量密度、高耐热性和低介电损耗的介电聚合物是先进电力电子应用的理想材料，例如用于电容器的高温储能薄膜。由于高极化和低介电损耗是两个相互矛盾的性质，因而只能在高介电常数(ε_r)和较低的损耗之间争取最佳的平衡。对于本征型聚合物电介质，介电常数源于电子、原子和偶极极化。然而由于聚合物分子链的性质，碳氢基电介质的电子和原子极化的介电常数被限制在5以下，偶极极化提高固有介电常数是有效的。为此围绕实现本征偶极玻璃聚合物高介电常数获得高储能密度的同时降低介电损耗的设计策略展开，从主链和侧链角度分析冻结链动力学阻止电子传导降低介电损耗的可行性，同时从电子结构角度揭示抑制传导电流的机制，在保持高ε_r和高玻璃化转变温度(t_g)的同时实现高温下高的储能密度，最后对薄膜电容器用极性聚合物研发的难点和重点进行总结和展望。     

高介电聚丙烯基纳米复合薄膜介电及储能性能抗老化特性

该文以一种具有新型介电特性的聚丙烯基纳米复合薄膜为研究对象,通过与德国创思普公司以及我国百正公司的双轴拉伸聚丙烯(BOPP)薄膜进行对比,基于试验重点研究三类薄膜热老化行为对薄膜结构变化和介电性能的影响,发现随老化时间的延长,BOPP的相对介电常数和损耗均有所升高,而复合薄膜的相对介电常数下降;另外,所有样品的储能特性都随着热老化时间的增加而下降。研究结果表明,热老化前后高介电聚丙烯基纳米复合薄膜的相对介电常数和储能密度均优于两种BOPP薄膜。因此聚丙烯基纳米复合薄膜是一种高相对介电常数、具有较好储能性能电介质薄膜,可用于制备具有高储能密度的薄膜电容器。     

聚丙烯纳米复合材料的介电特性研究

目前电力系统中容性设备是占地面积较大的设备之一,随着柔性直流输电技术的发展,提高容性设备的储能密度、减小设备体积成为迫切需要解决的问题。提高电容器电介质储能密度的途径主要是提高相对介电常数和击穿场强,通过向有机聚合物基体掺杂无机纳米材料是电介质材料改性的方法之一。本文测试了不同氧化钛含量样品的相对介电常数和直流击穿场强,对比分析了纯聚丙烯样品和聚丙烯/氧化钛复合材料样品的陷阱参数。结果表明,氧化钛的掺杂会在复合材料中引入界面区,从而影响材料的介电特性。氧化钛质量分数为9%的样品相对介电常数最高,相对纯聚丙烯样品增大了23.95%;而氧化钛质量分数高于0.1%时,击穿场强则随氧化钛含量的增加而降低。     

蒸镀Al_2O_3复合聚丙烯薄膜及其电容器性能研究

为提升聚丙烯薄膜击穿场强,将氧化铝蒸镀在聚丙烯薄膜表面,形成复合介质薄膜。将蒸镀氧化铝的薄膜进行金属化蒸镀,制成电容器,并对其性能进行测试,结果表明虽然复合薄膜的相对介电常数无明显变化,但电容器的击穿场强上升。复合薄膜电容器具有良好的自愈性能,可实现"隔离自愈",可有效地防止由于出现超限自愈而导致的电容器短路击穿。     

高储能密度复合绝缘材料的研究

本文利用高性能聚酰亚胺树脂为基体材料,与不同组成、不同比例的BaTiO3粉末复合,制备了高密度聚合物复合绝缘材料,并研究了其电性能.实验发现随着BaTiO3含量的增加,复合材料电阻率下降,相对介电常数升高,介质损耗角正切提高.所制备的试样介电常数超过了30,直流下击穿场强大于300kV/cm.还介绍了高储能密度复合绝缘材料和固体Blumlein及其应用的现状和发展.     

新型高储能密度聚合物基绝缘材料

新型高储能密度聚合物基绝缘材料由于应用潜力巨大,在近些年来发展速度很快。本文简单介绍该材料的重要性,解释电介质材料的储能机理、介电常数、电位移、击穿场强与储能密度之间的关系,以及计算储能密度和充放电效率的方法,然后分别对聚合物电介质和复合电介质材料研究进展进行概述,重点讨论材料的制备策略、加工工艺、微观/宏观机理分析和性能表征,并在文章最后对高储能密度聚合物基绝缘材料进行总结和展望。     

Structure,Ferroelectric, Dielectric and Energy Storage Studies of Ba0.70Ca0.30TiO3, Ba(Zr0.20Ti0.80)O3 Ceramic Capacitors

Ba_0.70Ca_0.30TiO₃-(BCT),Ba(Zr_0.2Ti_0.8)O₃-(BZT) ceramics were fabricated by conventional mixed oxide route to develop inorganic dielectric materials suitable for use as an insulator with high dielectric constant and low energy loss for capacitor applications. The structural phase transition, ferroelectric, dielectric and energy storage properties of BCT, BZT ceramic capacitors were investigated. Room temperature X-ray diffraction (XRD) patterns revealed prominent peaks corresponding to tetragonal perovskite crystal structure for both BCT, BZT solid solutions. Slim ferroelectric hysteresis (P-E) loops were observed for BCT, BZT solid solutions. Temperature dependent dielectric property measurements of BCT, BZT solid solutions have shown a high dielectric constant and low dielectric loss. Room temperature (300K) breakdown field strength and energy densities were obtained from the integral area of P-E loops. For the BCT ceramics, the largest recoverable energy (unreleased energy) density is 1.41 J/cm³ with dielectric breakdown strength as high as 150 kV/cm. For the BZT ceramics, the largest recoverable energy (unreleased energy) density is 0.71 J/cm³ with dielectric breakdown strength as high as 150 kV/cm. Bulk BCT, BZT ceramics have shown interesting energy densities; these might be the strong candidate materials for capacitor applications.     

Magnetron sputter-deposited multilayer (BaxSr1x)Ti1+yO3+z thin films for passive and active devices

Abstract

High permittivity (Ba_xSr_1?x)Ti_1+yO_3+z(BST) thin films are being investigated for integration into charge storage dielectrics and electric-field tunable elements for high frequency devices. For the latter application, it is desirable to have BST capacitors with high tunability and low losses. Therefore, we investigated the use of multilayer BST thin films consisting of very low dielectric loss BST/electrode interfacial layers ((Ba+Sr)/Ti = 0.73) sandwiching a high tunability, high permittivity primary BST layer ((Ba+Sr)/Ti = 0.9). BST capacitors with multiple layers of controlled composition can be effectively produced insitu by magnetron sputter deposition, using a single stoichiometric target and controlling the layer composition by changing the total process gas (Ar+O<₂) pressure. The layered BST film capacitors exhibit simultaneous low loss (tan Δ = 0.005), high tunability (76%), high charge storage energy density (34 J/cm³), low leakage, and high dielectric breakdown (>2.8 MV/cm).     

电容器级新型储能电介质的储电性能研究

在电容型储能脉冲功率电源中,脉冲电容器的储能密度直接影响脉冲功率电源和脉冲功率系统的小型化发展。目前,脉冲电容器的介质材料多采用双向拉伸聚丙烯薄膜(BOPP),其储能密度很难进一步提升,因此需要研究新型电容储能材料,以提高电容器的储能密度。本文以电容器用储能电介质为研究对象,对聚合物基无机纳米复合电介质(PVDF/TiO₂)、聚合物基全有机复合电介质(PVDF/PP)和高偶极矩无定形聚合物(ArPU)3种新型储能电介质的电性能参数作了对比。此外,测试并绘制了他们的D~E曲线,并以BOPP为参考,对他们的放电效率进行了研究。测试结果表明,这3种新型储能电介质的放电效率均随频率的升高而升高。     

Breakdown of YBCO thin films during current limiting and methods of improving current limiting performance

We performed fault current limiting tests using YBCO thin films and investigated the reasons for their breakdown during current limiting. There were two patterns of film breakdown. One occurred immediately after current limiting and the other occurred during current limiting. In film breakdown, the quench propagation speed showed almost no change with increasing energy consumption per unit time, but the energy consumption per unit area increased with increasing energy consumption per unit time. Therefore, local areas of the film reached the melting point and arcing occurred. It is therefore concluded that the performance of the films can be improved by decreasing the energy consumption per unit time. Connecting a parallel capacitor to the film in order to limit the energy consumption per unit time is proposed and tested as a measure to improve the current limiting performance of thin films. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(1): 20–27, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20709     

A Highly-Sensitive Ba(Ti1—xSnx)O3 Thin Film Dielectric Bolometer for Uncooled IR Sensor

Ba(Ti_1—xSn_x)O₃ (BTS) ferroelectric thin films have been prepared by metal-organic decomposition method whose final annealing temperature was optimized to 700°C for dielectric bolometer. High temperature coefficient of dielectric constant (TCD) of 1–3%/K and low dielectric loss of 0.04 have been obtained in x = 0.15 and 0.17. Field-induced pyroelectricity of the BTS film was calculated to be an excellent value as high as 750 nC/cm²K. A series of dependence of DB output level were examined on important operation factors. The DB output level was increased when the period of supply voltage waveform is longer than both the electrical and thermal time constant of the DB detector. Finally, a stable infrared detection at temperature lower than 30°C was confirmed.     

Breakdown behavior of oil-impregnated polypropylene as dielectricin film capacitors

The dielectric breakdown behavior of thin metalized PP films for use in HV capacitors was studied as function of temperature with and without rape-seed oil as impregnation medium. The impregnating oil penetrates into the amorphous regions of the dielectric. With oil impregnation, the dielectric breakdown strength of the PP film is increased by >25%. A correlation between the breakdown strength and the degree of impregnation was found. With increasing temperature the breakdown strength of PP films decreases. Moreover, the measurements showed abrupt changes of slope in the breakdown strength at defined temperatures. From these results a correlation was established between the dielectric breakdown strength of PP films and temperature induced structure changes. It was shown that the abrupt changes of slope in the breakdown strength occurring at defined temperatures are due to the additives contained in the PP capacitor films used. Finally, guidelines for further development of impregnated PP films as dielectrics for high power capacitor applications are presented     

特高压换流站直流滤波电容器故障分析研究

针对常发的直流滤波器用直流电容器损坏事故,本文对特高压换流站直流滤波电容器事故的机理和原因进行深入的研究,对电容器单元进行了外观和电性能测试、绝缘油色谱试验、电容量介质损耗测量.对解剖后的电容器元件绝缘包封、电容器元件不同温度下直流电压击穿、聚丙烯薄膜不同温度下交直流电压击穿、铝箔等进行了研究试验.通过对故障和完好电容器对比试验研究,发现所测电容器的部分生产工艺和注油工艺不佳造成运行中电容器不稳定,而电阻过于集中,导致电阻器表面绝缘介质过热,容易发生击穿故障,研究结果对提高该类型电容器的运行可靠性具有重要意义.     

超级电容储能的并联电能质量调节器

提出了一种应用超级电容作为储能元件、综合改善电能质量的并联型电能质量调节装置。装置在系统正常运行条件下可以滤除负荷产生的谐波、补偿无功功率，而且利用超级电容极高的功率密度，补偿负荷的快速波动功率，使电源侧只需向负荷提供单位功率因数、预先设定的恒定有功功率。当系统发生短时供电中断时，装置的电源侧配置的固态高速开关动作，使其和负荷脱离系统，装置发挥UPS的作用，向负荷短时提供全部功率。仿真研究表明，并联电能质量调节器在有效改善负荷品质，提高电能质量的同时，增强了负荷的供电可靠性。     

A high-capacitance PZT-on-Ta2O5 memory cell with a chemically stable electrode suitable for sub-micron processing

A high-capacitance Pb (Zrx, Ti1-x)O3 (PZT)-on-Ta2O5 memory cell suitable for sub-micron processing is proposed, and an experimental capacitor of PZT (Zr/Ti= 52/48)-on-Ta2O5 with Ta electrode was prepared. The X-ray diffraction and XMA analysis of the sample showed that PZT reacted with neither Ta nor Ta2O5. The capacitor with 500 nm PZT thickness shows current density of 10-8 A/cm2 at 4MV/cm, the breakdown field of 8MV/cm, and the effective dielectric constant of 40.     

聚合物基复合薄膜的高温储能性能研究进展

聚合物薄膜电容器具有功率密度大、安全性高、绝缘性好等优点而被广泛应用在工程领域。近年来,随着新能源交通、清洁能源并网、油气开采等领域对具有优异高温储能特性的介电薄膜电容器需求日益增加,高温、高电场等极限条件下介质薄膜电容器的储能受到越来越多的关注,相关研究已成为电工材料领域的研究热点。该文总结近年来有关聚合物基复合薄膜的高温储能研究进展。首先,介绍决定电介质材料高温储能特性的关键参数,分析高温、高电场对相关参数的影响规律;其次,梳理基于不同空间层次设计的聚合物薄膜高温储能特性优化研究现状,从分子结构、微观结构、介观结构3个方面总结高温储能性能的调控方法;最后,对进一步提升聚合物薄膜的高温储能性能做出展望。