| Title |
Comprehensive Loss Analysis of Planar Transformer in LLC Resonant Converter |
| Authors |
Daehyun Ra ; Younghoon Cho |
| DOI |
https://doi.org/10.6113/TKPE.2026.31.3.190 |
| ISSN |
1229-2214(pISSN), 2288-6281(eISSN) |
| Keywords |
LLC resonant converter; Planar transformer; Dowell’s equation; Improved generalized Steinmetz equation (iGSE); Finite element analysis (FEA) |
| Abstract |
This paper presents a comprehensive analysis of the losses in a planar transformer used in an LLC resonant converter. The copper loss and core loss of the transformer are analytically calculated and verified through finite element analysis (FEA) simulations. The copper loss is calculated using Dowell’s equation, considering both skin effect and proximity effect to accurately model the AC resistance under high-frequency conditions. For the core loss, the modified Steinmetz equation, the improved generalized Steinmetz equation (iGSE), and the improved-iGSE are applied to effectively predict losses under non-sinusoidal flux density variations. The calculation results are compared with the FEA simulation results, showing an error of 0.0016 pu for the copper loss and 0.000065 pu for the core loss estimated by iGSE. |