In pursuit of a carbon-neutral society, enhancing the performance and expanding the application of power electronics devices, such as power semiconductors and inverter-driven motors, is crucial. However, from the perspective of electrical insulation, devices and components are exposed to complex electric field stresses, including abrupt surges. Therefore, appropriate insulation design is essential. In our research lab, we are developing numerous innovative measurement techniques to sensitively observe and understand localized insulation breakdowns, such as partial discharges and insulation degradation (electric trees). Our studies propose methods to enhance insulation resilience and understand the mechanisms of degradation progress.

In the electrical power system, sulfur hexafluoride gas (SF6) has been widely used for current interruption and insulation due to its excellent performance. However, due to its extremely high global warming potential, recent efforts have focused on developing alternative insulation technologies. Our research is dedicated to modeling insulation breakdown phenomena and employing numerical simulations to precisely predict the insulation performance of high-pressure dry air and vacuum as substitute insulation media.

As part of the future vision for air mobility, the electrification of aircraft is anticipated. However, propulsion motors and electrical systems face challenging insulation conditions during operation, including significant changes in pressure and temperature, along with exposure to high-frequency surge voltages. In such harsh conditions, our focus is on elucidating insulation performance in high-altitude and severe environments. We propose insulation design guidelines specifically tailored for electric aircraft and actively engage in research and development to establish optimal insulation fault diagnosis techniques based on discharge mechanisms.