对击穿后的导光管式高隔离电压光电耦合器的内部损伤痕迹的研究表明, 高电压下器件内部的局部放电引起的持续烧蚀导致了前后级之间的击穿。分析局部放电的部位后, 结合附近存在气隙缺陷的情况, 在ANSYS下对气隙附近的电场强度分布进行了建模计算。结果表明：局部放电是因气隙内空气的低介电强度所致, 并因导电胶的渗透得到加强。在采取结构与工艺措施避免气隙缺陷与导电胶渗透之后, 局部放电得到消除, 导光管式高隔离电压光电耦合器的最低击穿电压(VISO)从23.8kV提高到了33.5kV。

The internal damage traces of the light-pipe-type high-isolation-voltage optocoupler after breakdown were studied. It was indicated that the continuous ablation caused by partial discharge under high voltage leads to breakdown between the front and rear stages. After analyzing partial discharge positions and considering the air gaps defects nearby, the electric field intensity distribution near the air gap was calculated with ANSYS software, which showed that the partial discharge was caused by the low dielectric strength of air in the air gap, and was enhanced by conductive adhesive infiltrating. After taking structure and process measures to avoid air gap defects and conductive adhesive infiltrating, partial discharge was eliminated, and minimum breakdown voltage (VISO) of the optocoupler was increased from 23.8kV to 33.5kV.