Power device reliability assessment in high pulsed power resonant converters

This paper considers the semiconductor thermal cycling monitoring of high power resonant converters. For the tests a single phase resonant converter rated at 1 kV, 250 A (250 kW peak power, duty ratio 10%, 25 kW average power, pulse length 1 ms) has been developed. This represents one phase of a multi-phase resonant power supply designed for long-pulse modulation (typically 1 ms-2 ms) when equipped with a suitable output transformer. Pulsed operation is obtained by direct modulation of the high frequency power supply. The main aim of the work reported here is developed a physic-based multi-chip IGBT structures and experimentally monitoring the chip temperature using high speed thermal imaging, during the pulse, to identify the limitations and reliability of the modulator technology proposed. The paper provides a brief overview of the prototype test rig. Simulations including multi-chip structures, experimental results and high quality chip thermal images are provided to validate the effectiveness of the proposed approaches.