Model-Agreement-Aware Multi-Objective Optimization for High-Frequency Transformers in EV Onboard Chargers


Kırcıoğlu O., Çamur S.

ENERGIES, vol.19, no.4, pp.1000, 2026 (Scopus)

  • Publication Type: Article / Article
  • Volume: 19 Issue: 4
  • Publication Date: 2026
  • Doi Number: 10.3390/en19041000
  • Journal Name: ENERGIES
  • Journal Indexes: Scopus, Compendex, INSPEC, Directory of Open Access Journals
  • Page Numbers: pp.1000
  • Kocaeli University Affiliated: Yes

Abstract

Developments in electric vehicle (EV) technology are pushing on-board chargers (OBCs) toward higher power density and efficiency, making high-frequency transformer loss prediction a critical design bottleneck. However, the accuracy of commonly used analytical winding-loss models varies strongly with frequency, conductor type (Litz/solid), window fill factor, and winding layout (e.g., interleaved), which can render single-model-based optimization unreliable. In this study, six analytical copper-loss models from the literature were independently reimplemented in a unified Python 3.11.5 workflow with a standardized interface to enable fair comparison under identical geometry and operating conditions. The models were benchmarked against 2D finite-element simulations on test scenarios with increasing physical complexity, including high fill-factor Litz windings and interleaved arrangements. The results confirm a regime-dependent behavior: no single model consistently outperforms others across the full design space, and model dispersion increases in geometrically stressed and higher-frequency regions. To manage this uncertainty, variance maps were generated and model disagreement was quantified using the coefficient of variation (CV). Finally, a reliability-oriented multi-objective optimization framework based on NSGA-II was developed, where a SmartTransformerRouter selects a reference loss estimate per candidate and CV is incorporated via constraints/penalties, with optional FEM triggering in high-uncertainty regions.