Deterioration Evaluation of Irradiated Insulation Materials used for Power Electronics

Recent electrical insulation designs for power electronics under severe environments such as high radioactive rays are required for the applications to high altitude and/or high radiation environments. Under above environments, the deteriorations of the insulation materials used for power electronics due to charging are concerned. With respect to the high radiation environments, the exposure of high-energy charged particles such as protons, electrons, etc. to the insulation materials gives rise to the charge accumulations that may induce dielectric BD (breakdown) of the materials and make the power electronics inoperable. Therefore, in this paper, we report the feasibility study on the deteriorations of BD characteristics of four insulation materials (Alicyclic EP, OCN, PPS, BPA) due to proton or electron irradiation. As a result, it was found that BDE (BD electric field) of some insulation materials (Alicyclic EP, OCN) decreases due to proton or electron irradiation. The oxidation and the change in the electric field distribution in the materials caused by proton or electron irradiation may be one of the reasons for the decreases in BDE of the materials.