高压大功率IGBT用液晶环氧性能研究(二):电气绝缘特性  

Research on Properties of Liquid Crystalline Epoxy for High-Voltage and Large-Power IGBT(Part 2):Electrical Insulation Performance

作　　者：王争东 曹晓龙 杨淦秋 罗盟 周远航 Wang Zhengdong;Cao Xiaolong;Yang Ganqiu;Luo Meng;Zhou Yuanhang(School of Mechanical and Electrical Engineering Xi'an University of Architecture and Technology,Xi’an 710055 China)

机构地区：[1]西安建筑科技大学机电工程学院,西安710055

出　　处：《电工技术学报》2025年第3期878-889,共12页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金青年项目(52307028);电力设备电气绝缘国家重点实验室开放课题(EIPE22210);陕西省自然科学基金青年项目(2022JQ-300);陕西省产学研协同创新计划项目(2023YFBT-45-02);陕西省教育厅服务地方专项产业化培育重点项目(23JC042)资助。

摘　　要：高压大功率IGBT用灌封材料绝缘失效是制约其快速发展的关键因素之一。由两篇论文组成的系列论文旨在通过构建液晶畴的研究思路协同提升环氧绝缘灌封材料的导热、耐热和电气绝缘性能。该文是系列论文(二),对液晶环氧树脂的击穿特性、局部放电、陷阱能级和介电特性等进行了研究,研究结果表明,通过π-π自组装构筑的液晶畴可有效地降低环氧固化后的自由体积,进而抑制载流子迁移,与双酚A型环氧相比,展现出更高的击穿场强(126.72 kV/mm)和更低的局部放电量(1.37 pC)。热刺激去极化电流研究表明,该联苯环氧-联苯固化剂双液晶交联材料具备较高的陷阱能级,捕捉电子能力增强。此外,利用分子动力学模拟软件仿真计算了交联体系的自由体积、电场下均方位移、击穿场强等参数,并对材料的电气性能机理进行了分析。研究结果可为新型环氧树脂在高压大功率IGBT灌封绝缘材料领域的工程应用提供一定的参考。Encapsulating materials with high thermal conductivity excellent heat resistance and electrical insulation have great application prospects in the field of high-voltage and large-power insulated gate bipolar transistors(IGBT).All organic liquid crystalline epoxy is a good candidate because of its theoretically high thermal conductivity,high glass-transition temperature,and outstanding electrical insulation performance.It can be attributed its unique liquid crystalline self-assembly ordered domains and a mass of rigid molecular structures.More importantly,the two new epoxy monomers have low viscosity under high temperature conditions,which is very suitable for potting process of epoxy for the encapsulation of IGBT.Therefore,it has great advantages in the future application of encapsulation of high-voltage and large-power devices.In this work,a novel liquid crystalline epoxy(named TMB-5+) with dual mesogenic units was constructed.Benefits by ordered liquid crystalline domains and a large number of rigid structures,the new liquid crystalline epoxy exhibits excellent heat resistance and thermal conductivity.The related research was presented in the first paper of this work.This paper is the second in a series of papers,which investigates the electrical insulation performance of liquid crystalline epoxy.Firstly,the dielectric breakdown strength of the new liquid crystalline epoxy film was studied.The study showed that the TMB-5+ sample containing double mesogenic units exhibited a higher breakdown strength,reaching 126.72kV/mm,which was 46.9% higher than traditional epoxy.The higher phenyl content and denser liquid crystalline domains in the TMB-5+ sample were considered to be beneficial for improving the breakdown strength.Base on simulation of the free volume and mean square displacement of the new epoxy,we found that the liquid crystalline epoxy has lower free volume parameters and weaker movement ability of molecular chain under the electric field.These factors also showed positive impacts on improving the breakdo

关 键 词：绝缘灌封材料 联苯液晶环氧 联苯液晶固化剂 电气性能 分子动力学模拟 

分 类 号：TM211[一般工业技术—材料科学与工程]