A Cryogenic Isolated Gate Drive Circuit for Medium-Voltage Medium-Current IGBT Modules

Future zero-emission all electric aircraft may require cryogenic power electronics converters to establish the power train. The state of the art of cryogenic power electronics mainly focus on the behavior of power semiconductor devices and passive components in cryogenic temperature. There is no experimental demonstrations of an isolated gate drive circuit driving a power semiconductor device in cryogenic temperature. Instead, in published cryogenic converters, isolated gate drive circuits are placed outside of the cryogenic environment. The extended wiring increases parasitic impedance of the gate drive loops and limits systematic integrality. This paper thereby presents a design and demonstration of an isolated gate drive circuit that is capable of driving a medium-voltage medium-current IGBT in <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$-196^{\circ}\mathrm{C}$</tex> environmental temperature. The isolated gate drive circuit include an isolated power supply, a digital isolation barrier and a linear voltage regulator, all of which are built with discrete components and are cryogenic-proven. Two identical isolated gate drive circuit prototypes are built and mounted on a 1700V/600A-rated IGBT half-bridge power module. A double pulse test is firstly performed with both the gate drive circuits and the IGBT power module immersed in liquid nitrogen. The low-side IGBT is successfully turned-on and -off at 800V/160A with latency matched with datasheet specification. Then, a continuous switching test is performed. In liquid nitrogen environment, the high-side and the low-side IGBTs switch complementarily at 2 kHz under 800V bias voltage. The capability of the isolated gate drive circuit to drive circuits with bridge configurations in cryogenic temperature is thereby verified.