Design, FEA-Based Physical Insights, and Experimental Verification of a Planar Transformer for Two-Switch Flyback Converters

Naelton O. de Souza; Djonny Weinzierl; Maicon W. M. de Carvalho; Rodrigo Heinrich; Sergio V. G. Oliveira

doi:10.18618/REP.e202623

Authors

Naelton O. de Souza Nidec Aerospace https://orcid.org/0000-0003-3497-1975
Djonny Weinzierl Universidade do Estado de Santa Catarina
Maicon W. M. de Carvalho Universidade do Estado de Santa Catarina
Rodrigo Heinrich Universidade do Estado de Santa Catarina
Sergio V. G. Oliveira Universidade do Estado de Santa Catarina https://orcid.org/0000-0002-2862-3870

DOI:

https://doi.org/10.18618/REP.e202623

Keywords:

Finite element analysis, Double-switch flyback, Planar transformer, AC resistance, Leakage inductance, Stray capacitance

Abstract

Parasitic parameters in high-frequency transformers directly impact losses, electromagnetic interference (EMI), and voltage/current stresses in power converters. This paper presents a comparative analysis and optimization of planar transformers (PT) applied to a two-switch Flyback (TSF) converter. The investigation focuses on balancing leakage inductance, AC resistance, and parasitic capacitances through different PCB winding arrangements using multiphysics Finite Element Analysis (FEA). By employing a structured analysis that correlates electromagnetic and thermal modeling with experimental validation, this work demonstrates how layer alignment and interleaving mitigate proximity effects and drastically reduce ringing in semiconductor switches. The results show that the optimized configuration achieved an 80% reduction in leakage inductance and a 57% reduction in AC resistance compared to conventional designs, resulting in an efficiency of 89.2% and a significant decrease in thermal stress. The study provides evidence-based design guidelines for mitigating parasitic effects in high-power-density converters.

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Author Biographies

Naelton O. de Souza, Nidec Aerospace

was born in Criciúma, SC, Brazil, in 1986. He received his B.S. (2014) and M.Sc. (2018) degrees in electrical engineering from the State University of Santa Catarina (UDESC). He is a PCB layout specialist with over 15 years of experience enabling reliable, manufacturable, and high-performance electronic platforms compliant with IEC, UL, and IPC standards. He began his career in the R&D team at Embraco Electronics (now Nidec Global Appliance), working on PCB-level design of drives and electronic control systems for high-efficiency household appliances. In early 2015, he joined WEG Drives & Controls as an Electronic Designer, developing PCB layouts for industrial drives, covering power electronics and high-density control boards. Throughout his career, he has contributed to complex PCB developments involving high-voltage, high-current-density, mixed-signal integration, thermal constraints, and manufacturing scalability across industrial drives, EV charging infrastructure, traction systems, BESS power conversion platforms, and BMS hardware. As of April 2026, he serves as a PCB Design Electronics Engineer at Nidec Aerospace, focusing on advanced PCB layout for mission-critical aerospace power electronics and high-reliability control hardware supporting next-generation sustainable aviation technologies.

Djonny Weinzierl, Universidade do Estado de Santa Catarina

was born in São Bento do Sul, SC, Brazil, in 1976. He received his B.S. degree in electrical engineering from the Regional University of Blumenau (FURB) in 1999, and his Ph.D. degree in electrical engineering from the Federal University of Santa Catarina (UFSC) in 2004. As part of his doctoral research, he conducted academic activities at the Brandenburg University of Technology in Cottbus, Germany, from 2002 to 2003. In 2008, he completed a post-doctoral fellowship at the University of São Paulo (USP). He is currently a Senior Post-Doctoral Researcher at the State University of Santa Catarina (UDESC), funded by FAPESC, focusing his research on the computational modeling of power electronic converters.

Maicon W. M. de Carvalho, Universidade do Estado de Santa Catarina

was born in Rio Grande, RS, Brazil, in 1991. He received his B.S. degree in electrical engineering from the State University of Santa Catarina (UDESC) in 2017, where he is currently working toward his M.Sc. degree in electrical engineering. He is also an electrical engineer for the Municipality of Navegantes, SC, Brazil. His research interests include electromagnetic compatibility, renewable energy microgrids, modular systems, distributed energy resources, and the design of magnetic components.

Rodrigo Heinrich, Universidade do Estado de Santa Catarina

was born in Rio do Sul, SC, Brazil, in 1995. He received his B.S. and M.Sc. degrees in electrical engineering from the State University of Santa Catarina (UDESC), Joinville, Brazil, in 2017 and 2020, respectively, where he is currently working toward his Ph.D. degree in electrical engineering. From 2018 to 2020, he was a researcher on the EMBRACO/UDESC joint project on advanced electronic controls applied to cooling systems. Since 2021, he has been an electrical engineer at the electrical distribution company of the State of Santa Catarina (CELESC).

Sergio V. G. Oliveira, Universidade do Estado de Santa Catarina

(S’00–M’05–SM’20) was born in Lages, SC, Brazil, in 1974. He received his B.S. degree in electrical engineering from the Regional University of Blumenau (FURB) in 1999, and his M.Sc. and Ph.D. degrees in electrical engineering from the Federal University of Santa Catarina (UFSC), Florianópolis, Brazil, in 2001 and 2006, respectively. He has been a Professor of Power Electronics at FURB since 2004 and at the State University of Santa Catarina (UDESC) since 2012. He is a recipient of the CNPq Technological Development and Innovative Extension Productivity Fellowship (DT-2). Dr. Oliveira is a researcher at the National Institute of Science and Technology in Power Electronics (INCT-EPTech) and was elected President of the Brazilian Institute of Power Electronics and Renewable Energies (IBEPE) for the 2026–2029 tenure. He is an active member of SOBRAEP and the IEEE Industrial Electronics (IES), Power Electronics (PELS), and Industry Applications (IAS) societies. His research interests include integrated electric drives, solid-state transformers, power converters for electric traction systems, cybersecurity in power electronics, and reliability-oriented design in power electronics.

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