Design and Study of Interleaved and Face to Face Magnetic Microtransformers

Abstract

The aim of this paper is to compare two types of microtransformers using the High Frequency Structural Simulation simulator. Interleaved and face to face transformers were studied for applications in dc/dc converters and variable speed drive. These transformers have a magnetic material core (yttrium iron garnet) and square spiral windings. The main purpose of the use of magnetic material is to increase the magnetizing inductance L F and the coupling factor k. For this, L F and k were studied by simulation as a function of turn spacing, magnetic, and insulating layer thicknesses. The results presented were compared with recently published works. An important improvement of the main properties was observed in the frequency range (10-100 MHz). The interleaved transformer properties are equal to 0.95 and 0.80 µH for k and L F parameters, which corresponds to an 0.05 µH/mm 2 inductance area ratio (L F / A), whereas for the face to face transformer k and L F are equal to 0.9 and 0.78 µH for an 0.08 µH/mm 2 inductance area ratio. Interleaved transformers were manufactured and characterized. Results show close agreement between simulation and measurement results.Index Terms-Coupling factor, face to face transformer, interleaved transformer, magnetic material.

A Review and Comparison of Solid, Multi-Strands and Litz Style PCB Winding

“…Thanks to alternating layers with opposite currents, the net current in a Ampere contour was decreased in comparison with non-interleaving, thereby reducing MMF and flux density [4] (Figure 1). Some interleaving structures applied in planar transformers were also proposed in References [5][6][7][8] including same layer alternating and multi-layers interleaving. In addition, although interleaving methods are well-known for reducing leakage inductance, however, increasing contact area between the primary and secondary windings has increased parasitic capacitance between windings [2,9].…”

Flyback Micro-Converter Design with an Integrated Octagonal Micro-Transformer for DC-DC Conversion

“…[11][12] presented a numerical simulation study of the magneto-thermal behavior allowing for an improved design of a square planar coil sandwiched between two magnetic materials. [13][14] presented a method of dimensioning a square spiral planar coil integrated in high voltage converter application a photovoltaic. They visualized the density of the magnetic flux and the electric potential.…”