Evaluation of Electric Charge Accumulation in Insulation Layer of Power Module using Direct Current Integrated Charge Measurement

In this paper, we tried to evaluate the charge accumulation in insulating materials used for electronic power devices. Space charge accumulation is said that one of important factors to evaluate the insulating materials under dc high electric fields, especially at high temperature. While, the space charge accumulation in insulating materials has been measured using pulse electro acoustic (PEA) method, the PEA method has been mainly applied to sheet shape samples. Therefore, it is difficult to apply the PEA method to an insulating layers used for an actual electronic devices, which are usually composed of complicated shape. Therefore, we have tried to apply a direct current integrated charge measurement which is newly developed measurement method to evaluate the charge accumulation in the insulating layers. Using the method, we tried to estimate the charge accumulation in the insulating layer of actual power electronic devices under various electric stresses at various temperature. As the result, it was found that the method was preferably available to evaluate the characteristics of charge accumulation in the insulation layers of the power electronic devices.