N.Yu. Veretennikov1, A.V. Turetsky2, V.M. Pitolin3, K.D. Tsipina4

1-4 Voronezh State Technical University (Voronezh, Russia)

Formulation of the problem. In this paper, we consider the problem of optimizing losses caused by the proximity effect in windings with a decrease in the dimensions of transformers of flyback power converters. To optimize the losses and select the final topology of the transformer, an analytical method is used to calculate the losses caused by the proximity effect in magnetic components operating with energy storage. The correctness of the conclusions made on the basis of analytical calculations is confirmed by the results of modeling losses in transformers for various winding topologies. The simulation of losses caused by the proximity effect in magnetic components was used to evaluate the effectiveness of the proposed topologies, as well as to verify the analytical method for calculating losses. Modeling was carried out in the ANSYS Maxwell environment. The proposed topologies of transformers are made on an ER7.5 core with a cylindrical wire.

Purpose. it is reasonable to show that the alternation of conductive layers in magnetic components with alternating windings makes it possible to increase their efficiency when operating at high frequencies, which makes it possible to reduce their weight and size.

Results. When comparing the high-frequency effects that occur in transformers without interleaving and in transformers with alternating windings, the main difference lies in the mutual compensation of magnetic fields of the opposite direction when alternating winding layers in transformers. This difference ceases to hold for flyback transformers, where the currents in the windings flow alternately, and therefore the field cannot be compensated for by alternating the windings. This becomes the main disadvantage of flyback transformers, preventing an increase in the conversion frequency and a decrease in their dimensions. However, losses can be reduced by redistributing the field between the windings by alternating layers. Due to the fact that the dissipated power is proportional to the square of the currents at the layer boundaries, then by redistributing the fields at the layer boundaries in each cycle of the transformer, it is possible to reduce the proximity effect at the boundaries of each layer, and, as a result, reduce high-frequency losses in the windings.

Practical significance. The results obtained can be used in the design of high-frequency flyback transformers, which can significantly reduce the dimensions of the product by increasing the frequency of the magnetic component, while maintaining losses at an acceptable level.

Veretennikov N.Yu., Turetsky A.V., Pitolin V.M., Tsipina K.D. The problem of optimizing high-frequency losses in copper conduc-
tors when reducing transformer dimensions in flyback converters. Radiotekhnika. 2022. V. 86. № 7. P. 20−24.
DOI: https://doi.org/10.18127/j00338486-202207-04 (In Russian)

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