Pressure Tolerant Power Electronics

Abstract

The thermal behaviour of an IGBT module was investigated, especially with respect to the module being immersed in dielectric oil. An equivalent thermal model was built using thermal transients and network synthesis. The thermal behaviour was further investigated using thermocamera measurements and simple finite element models. Passive pressure testing of electronic components relevant for the test setup was performed. The testing showed no significant influence on the electrical behaviour of the components. An IGBT module without gel covering the chips was switched while immersed in dielectric oil. The switching transients were compared to the case of a normal module switching in air. Only minor differences were found between the switching waveforms from the two cases. A test was performed where water was added to the dielectric oil in order to reduce the breakdown voltage of the oil. No breakdown phenomena were observed for the voltages that were tested. A brief litterature study regarding stray inductance considerations in the test setup was performed.