Inductor geometries with significantly reduced height

The “constant-flux” concept is leveraged to achieve high magnetic-energy density, leading to inductor geometries with height significantly lower than that of conventional products. Techniques to shape the core and to distribute the winding turns to shape a desirable field profile is described for the two basic classes of magnetic geometries, those with the core outside the winding and those with the core inside the winding. A relatively constant flux distribution is advantageous not only from the density standpoint, but also from the thermal standpoint via the reduction of hot spots, and from the reliability standpoint via the suppression of flux crowding. Design and fabrication results are delineated for a core-outside inductor with same specifications as a commercial counterpart, but with smaller footprint as well as smaller height. Prototype cores and windings were milled from powder-iron disks and copper sheets, respectively. The volume of the prototyped constant-flux inductor is 66% the volume of a commercial inductor with same inductance and dc resistance.