| Abstract |
In high current, high frequency inductors and transformers foil windings will be competitive with other types like litz wire if they are properly designed. Effective loss calculation tools presented by Dowell [2], Jongsma [3] and Carsten [4] gives good control of the losses in foil windings used in transformers. In an inductor, problems arise due to the needed air gaps. A minimum loss design of a 100 kHz inductor with foil windings using a multi air gap approach is presented. In the design process finite element eddy current computations have been used extensively. A prototype has been constructed and tested. The inductor is supposed to be used in a 20 kVA Dual-Active-Bridge Inverter. The required inductance is 5 μH. In the final design, a multi air gap solution with 16 air gaps is used keeping the winding losses as low as 35 W at 75 A rated current. The additional losses rising from the fringe field near the air gaps is only 7 W at rated current. Our tests on the inductor verifies that all sources of high frequency winding losses are well under control. |
