电气工程学报 ›› 2021, Vol. 16 ›› Issue (2): 50-59.doi: 10.11985/2021.02.007

• 特邀专栏:高压电工装备绝缘 • 上一篇    下一篇

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聚丙烯载流子输运与能量积累调制直流击穿威布尔分布特性仿真研究

蔡姝娆1(), 高梓巍1, 纪民尊1, 姚佳池1, 李鹏新1, 闵道敏1(), 李盛涛1, 武庆周2   

  1. 1.西安交通大学电力设备电气绝缘国家重点实验室 西安 710049
    2.中国工程物理研究院流体物理研究所 绵阳 621900
  • 收稿日期:2021-03-01 修回日期:2021-04-28 出版日期:2021-06-25 发布日期:2021-08-05
  • 通讯作者: 闵道敏 E-mail:3386726546@qq.com;forrestmin@xjtu.edu.cn
  • 作者简介:闵道敏,男,1985年生,副教授,博士研究生导师。主要研究方向为聚合物纳米复合电介质击穿机理与储能性能提升方法、聚合物纳米复合电介质界面区介观性质和击穿/储能特性的计算与仿真。E-mail: forrestmin@xjtu.edu.cn
    蔡姝娆,女,1998年生,硕士研究生。主要研究方向为聚合物基纳米复合电介质的界面区性质、高温击穿与储能性能的提升方法。E-mail: 3386726546@qq.com

Simulation of Carrier Transport and Energy Accumulation Modulated DC Breakdown Weibull Distribution in Polypropylene

CAI Shurao1(), GAO Ziwei1, JI Minzun1, YAO Jiachi1, LI Pengxin1, MIN Daomin1(), LI Shengtao1, WU Qingzhou2   

  1. 1. State Key Laboratory of Electrical Insulation and Power Equipment, Xi’an Jiaotong University, Xi’an 710049
    2. Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900
  • Received:2021-03-01 Revised:2021-04-28 Online:2021-06-25 Published:2021-08-05
  • Contact: MIN Daomin E-mail:3386726546@qq.com;forrestmin@xjtu.edu.cn

摘要:

聚丙烯因其优异的电气和化学性能被广泛应用于薄膜电容器,但直流电场中电介质的击穿是制约电容器储能密度提高的关键因素。外施强电场作用下,电极/绝缘电介质界面注入的电荷在电场力驱动下输运并积累能量,形成泄漏电流,积聚空间电荷、畸变电场,最终导致绝缘电介质发生击穿破坏。从载流子输运和能量积累造成绝缘电介质击穿的物理过程,提炼出决定击穿场强分散性的电荷注入势垒、试图逃逸频率、载流子迁移率、陷阱能级、陷阱密度和陷阱捕获概率六个电荷输运特征参数。将电荷输运特征参数设置为随机变量,采用电荷输运和分子链位移调制击穿模型仿真了载流子输运与能量积累过程,得到的击穿强度计算结果服从威布尔分布。建立了威布尔特征击穿强度与形状分布参数随不同电荷输运随机变量方差的变化关系:随着方差的增大,特征击穿强度基本稳定在试验值附近,形状分布参数由于击穿数据分散性增大而下降。对比各输运参数方差与威布尔分布的关系,发现威布尔分布对陷阱能级的依赖性较强,对试图逃逸频率和迁移率的依赖性较弱,对注入势垒和陷阱捕获概率的依赖性最弱。研究结果阐释了电荷输运随机变量通过调控载流子输运与能量积累改变击穿威布尔分布特性的作用机理。

关键词: 直流击穿威布尔分布, 形状分布参数, 电荷输运随机变量, 载流子输运与能量积累, 分子链位移与自由体积扩张

Abstract:

Polypropylene is widely used in thin-film capacitors for its excellent electrical and chemical properties. However, the dielectric breakdown under DC electrical field is the key factor restricting the improvement of the energy storage density of capacitors. Under the action of the external strong electric field, the charge injected from the electrode/dielectric interface is driven by the electric field force to transport and accumulate energy, forming leakage current, accumulating space charge, and distorting electric field, which eventually leads to the breakdown of the dielectric. Based on the physical process of dielectric breakdown caused by carrier transport and energy accumulation, six characteristic parameters of charge transport, including charge injection barrier, attempted escape frequency, carrier mobility, trap energy level, trap density, and trap capture probability, are extracted. The charge transport characteristic parameters are set as random variables, and the carrier transport and energy accumulation process are simulated by carrier transport and molecular displacement modulated electrical breakdown model. The calculated breakdown strength follows Weibull distribution. The relationship between Weibull characteristic electrical breakdown strength and shape distribution parameter with the variance of different charge transport random variables is established: with the increase of variance, the characteristic electrical breakdown strength is basically stable near the experimental value, and the shape distribution parameter decreases due to the increase of dispersion of breakdown data. Comparing the relationship between the variance of transport parameters and Weibull distribution, it is found that Weibull distribution has a strong dependence on trap energy level, a weak dependence on escape frequency and mobility, and the weakest dependence on injection barrier and trap capture probability. The results explain the mechanism of charge transport random variables changing the breakdown Weibull distribution by regulating carrier transport and energy accumulation.

Key words: Weibull distribution of DC breakdown, shape distribution parameter, charge transport random variables, carrier transport and energy accumulation, chain displacement and free volume expansion

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