Inductor design for cryogenic power electronics

The core losses of a number of ferrite compositions as well as several metallic ferromagnetic materials have been measured at 78 K. From these measurements we can estimate the power dissipation of a conventional inductor (copper windings, magnetic core) at low temperature. It is found that the magnetic losses generally increase on cooling; this counteracts the reduction in copper losses, and the dissipation would not be much different than its room temperature value. If superconducting windings are substituted for the copper, there remains a tradeoff between losses in the core and in the superconductor. Optimization of this combination will require extensive modeling; it may be that the best solution involves no magnetic core at all.