Constant-flux inductor with enclosed winding for high-density energy storage

The ‘constant-flux’ concept has been described in a recent Letter as a way to utilise space more efficiently for inductor geometry with the core enclosed by winding. While the concept can conceptually be extended to the companion case of the inductor with winding enclosed by the core, structural synthesis is complicated by the absence of circular symmetry. Thus, this Letter delineates a procedure to shape the core and distribute winding turns to realise a magnetic field profile that 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 constant-flux inductor with the same specifications as a commercial counterpart, but the total height of the inductor is reduced by a factor of two.