Inductor loss estimation of a single phase 3-level gallium nitride inverter under cryogenic conditions

Cryogenic cooling of power converters has been proposed as a method to increase power density and efficiency. In addition to the reduction in copper conduction losses at low temperatures, prior work has shown that the conduction loss of GaN devices also decreases under dc test conditions as the device temperature is lowered. In order to optimize the design of the full power converter at near-cryogneic operating temperatures, the impact of temperature on the losses of passive components must be understood. This paper outlines a method of estimating the losses of inductors at low temperature operation. Although the copper losses in the inductors clearly decrease with decreasing temperature, it was found that the overall losses remained relatively constant for a composite powdered iron inductor over the temperature range of 20° C to − 100° C.