Inductors and Transformers for Power Electronics

Medium frequency transformer leakage inductance modeling and experimental verification

“…On the other hand, in case of power electronic aplications, the operating frequencies are typically high and therefore the effect of the frequency on the leakage inductance has to be accurately modeled as well. The majority of the of the developed frequency dependent leakage models that can be found in the literature [4], [5], [8] are based on the Dowell's frequency dependent leakage inductance model for foil windings [9] and its generalization via the porosity factor.…”

100 kW, 10 kHz Medium-Frequency Transformer Design Optimization and Experimental Verification

“…where: Ra L -Rayleigh number, Pr -Prandtl number, ✏ -Emissivity, -Stefan-Boltzmann constant [28]- [30] zero power injection, thus reducing the admittance matrix of the thermal network, given in Fig. 5b, from (10x10) to (6x6) dimension as shown in (25) and (26).…”

Thermal modeling and experimental verification of an air cooled medium frequency transformer

“…This is a reasonable assumption which is very close to reality, due to the high temperature conductance of copper compared to the enamel insulation, which allows to indirectly include the effect of the different cooling conditions of both winding portions, inside and outside of the core window, on the winding hot-spot temperature in a simple manner, by putting in parallel their corresponding heat transfer resistances. Table I: Empirical heat-transfer formulas for conduction, convection and radiation [3,9,10] Conduction…”

“…Decreased cooling surface implies increased thermal resistances towards the ambient (cooling media) which result in higher temperature gradients. Therefore, accurate thermal modeling, that allows for adequate MFT thermal coordination at the design stage, plays an essential role in the search for the overall optimal design [3][4][5][6][7].…”