皮秒脉冲激光诱导压力波法测量金属化薄膜空间电荷

Space Charge in Metalized Film Measured by Picosecond Pulsed Laser Induced Pressure Pulse Method

金属化薄膜是重要的电容器卷绕材料,研究空间电荷效应对其绝缘性能提升至关重要。该文搭建皮秒脉冲激光诱导压力波(laser induced pressure pulse,LIPP)法空间电荷测量系统,以12和6μm厚金属化双向拉伸聚丙烯(biaxially oriented polypropylene,BOPP)薄膜为例,获得其在直流电场下的空间电荷分布。结果可知:同极性电荷量随施加电场增加,在强电场下存在非线性空间电荷效应;金属镀层一侧接负极条件非线性效应更强,但仍弱于薄膜与电极物理接触侧(非金属化一侧),后者向介质内部注入电荷明显,说明金属蒸镀较物理接触可以减弱界面电荷效应;随薄膜厚度减小,获得空间电荷峰宽度减少而峰前沿增加。所得结果证实了皮秒脉冲LIPP法测量10μm及以下金属化薄膜空间电荷分布的可行性,并为研究其空间电荷效应、绝缘性能优化提供一定参考。

Metalized films are important winding material for film capacitors,and investigating the space charge effect is critical for improving the insulation performance.In this work,a picosecond pulsed laser induced pressure pulse(LIPP)system for space charge measurement is built up.The space charge distribution in metalized biaxially oriented polypropylene(BOPP)films with a thickness of 12mm and 6mm is obtained as an example.It is verified that the amount of homopolar charges increases with the applied electric field,and when the applied electric field is strong,a non-linear effect appears,which is more pronounced for the metalized side with negative polarity.The even more significant non-linear effect and charge injection for the physical contacting(non-metalized)side indicate that the metallization can weaken the interface space charge effect.With the decrease of film thickness,the peak width of space charge decreases,while the front of the peak increases.The results in this work verify the feasibility of the picosecond pulsed LIPP method to measure the space charge distribution in metalized films with a thickness on the order of 10mm or thinner,and provide a reference for investigating the space charge effect and improving the insulation performance.