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to reprint or republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. Abstract— An improved calculation of ferrite core loss for nonsinu-soidal waveforms separates a(More)
— An extension to the Steinmetz equation is proposed, to enable estimation of hysteresis losses in magnetic core materials with nonsi-nusoidal flux waveforms. The new formulation is shown to avoid anomalies present in previous modified-Steinmetz-equation calculations of loss with nonsinusoidal waveforms. Comparison with experimental measurements in MnZn(More)
—The largest loss in an example litz-wire flyback transformer is found during current commutation between windings. In order to reduce this loss, a new optimization method is introduced. The new method optimizes strand size and number in litz wire considering cost and loss. Unlike previous methods, it is valid with two-or three-dimensional field geometry(More)
— The number and diameter of strands to minimize loss in a litz-wire transformer winding is determined. With fine stranding, the ac resistance factor can be decreased, but dc resistance increases as a result of the space occupied by insulation. A power law to model insulation thickness is combined with standard analysis of proximity-effect losses to find(More)
A numerical method is used to determine the winding shape that minimizes total winding losses in a gapped inductor with round-wire windings. The algorithm accounts for proximity-effect loss that results from the two-dimensional field in the winding area, and for the effect of the winding on that field. Results are presented for an example geometry. The(More)
—The squared-field-derivative method for calculating eddy-current (proximity-effect) losses in round-wire or litz-wire transformer and inductor windings is derived. The method is capable of analyzing losses due to two-dimensional and three-dimensional field effects in multiple windings with arbitrary waveforms in each winding. It uses a simple set of(More)
—Design of litz-wire windings subject to cost constraints is analyzed. An approximation of normalized cost is combined with analysis of proximity effect losses to find combinations of strand number and diameter that optimally trade off cost and loss. The relationship between wire size, normalized cost, and normalized loss is shown to have a general form(More)
— Multiphase voltage regulator modules (VRMs) for microprocessor power delivery with coupled output inductors are discussed. Strong coupling is shown to be feasible and effective at reducing ripple if the correct magnetic topology is used. For more than two phases, this can be a " ladder " core with windings around each rung. Typical ripple reduction is(More)
—A method is developed to use a single set of two-dimensional numerical optimizations of inductor winding shapes to simply calculate the optimal winding configuration for any design on the same core without repeating the computationally intensive numerical optimization. For transformer windings, the results are consistent with previous one-dimensional(More)