Localization of electrical-insulation and partial-dischargefailures of IGBT modules

The partial discharge (PD) and insulation resistance is very important in view of the increasing operating voltages of insulated gate bipolar transistor modules. PD spectroscopy showed that the PDs from metallization edges and interfaces in silicone gel were the main sources of PD at high voltages. It also allows these types of PDs to be clearly distinguished. As the PDs from interfaces in silicone gel increase strongly at high voltages, it is especially important for the silicone gel to adhere well to the ceramic