功率器件高电压封装用复合电介质灌封材料研究

Study on Composite Dielectric Encapsulation Materials for High Voltage Power Device Packaging

封装绝缘材料是电力电子器件中最主要的绝缘组件,它的特性决定了高电压功率器件的适用性。该文提出了一种添加纳米级颗粒碳化硅的硅凝胶复合电介质材料,该新型硅凝胶基复合电介质材料具有显著的非线性电导特性,文中首先研究了其中碳化硅填充颗粒的掺杂比例和服役工作温度对其直流电导特性的影响规律。随后,采用制备的新型硅凝胶基复合电介质研制了耐高电压的封装功率模块并进行了局部放电测试实验。实验结果确认了提出的新型复合电介质对于功率模块封装的绝缘耐受电压具有明显改善效果。60%碳化硅颗粒填充比例下,该复合电介质可显著降低功率模块内部电场强度。其中,模块局部放电起始电压可提升42.03%。最后,本文还验证了该新型复合电介质材料的热氧老化抗性及抗温度冲击可靠性。

The packaging insulation material is the most important part in power electronic devices,because it limits the applicability of the power devices in the trend of high voltage.In this paper,silicone gel composites with nonlinear electrical conductivity were prepared by doping silicon carbide nanoparticles with the silicone gel.The effects of the filler content and operating temperature on the DC conductance of the composites were discussed experimentally.Power modules were demonstrated using the composites for further partial discharge(PD)testing.The PD initial voltage of the power modules were improved in the proposed way.The results showed that the electric field distribution can be significantly homogenized by the composite with the 60vol%filler in the power module.The partial discharge initial voltage can be increased by 42.03%.Thermal oxygen aging testing and thermal shock testing were also carried out to verify the long-term reliability of the insulation composites.