Improved AC-Resistance of Multiple Foil Windings by Varying Foil Thickness of Successive Layers

Abstract: A novel optimization strategy for planar inductor design, based on a per-layer approach for calculation of the optimal foil thickness is presented in this paper. Implementation of this strategy results in reduced ac- and dcresistance of the winding. Inductor windings optimized for sinusoidal excitation were constructed and the resistance measured. Results are shown for air core inductors and the performance of the same windings in gapped magnetic cores is also reported. An optimisation technique for non-sinusoidal excitation is also proposed. Air gap proximity losses can be reduced by notching the winding in the region of the air gap. This technique combined with the newly proposed layer optimisation strategy is also investigated for a trapezoidal current waveform

Evaluation of a Quasi Coaxial Printed Circuit Board Transformer

Abstract: Minimization of leakage inductance of a transformer is very often one of the main focus points during the design because of the adverse effects it may have on some power electronics circuit topologies. There are however applications in which the leakage inductance may be used as a circuit element, in which case it should be predictable and easily realizable. Coaxial transformers are known for the ease with which the leakage inductance may be predicted but obtaining these values repetitively is still a problem because of the manner of manufacture. This work investigates the possibility of utilizing printed circuit board (PCB) technology to manufacture coaxial transformers and to increase the accuracy with which the desired leakage inductance may be obtained. Finite element methods (FEM) as well as experimental results are used to support the proposed ideas. A planar transformer is also analyzed in the same way to accentuate the design advantages offered by the proposed quasi-coaxial transformer

A high-density heat-sink-mounted inductor for automotive applications

Electrical Engineering, Mathematics and Computer Scienc