Reduction of proximity losses in coupled inductors

The paper presents an investigation into the leakage fields and eddy current losses in the windings of inductors and coupled inductors used in high frequency applications. It shows that the eddy current losses in the windings can be reduced significantly by the use of distributed airgaps, and that under these conditions the leakage fields are predominantly one dimensional so that the losses can be predicted analytically. Mutual losses produced by one winding in another are examined. It is shown how ferrite core designs can be modified to ameliorate further AC winding losses. These techniques taken together show that winding eddy current losses in inductors and coupled inductors can be reduced almost by an order of magnitude. Thus inductor efficiency can be improved, and the way becomes open for the design of inductors for higher frequency circuits.