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    Advanced Magnetic Materials and Geometries

    D11.9 - Low Profile, Laminated NiFe Transformers for High-Frequency LLC Resonant Converters

    Thursday, March 26, 2026
    12:00 PM - 1:45 PM CT
    Location: Poster 11
    This work presents the design, fabrication, and experimental validation of microfabricated laminated NiFe transformers for high-frequency LLC resonant converters. Two transformers were developed: T1, targeting 0.5-1.5 MHz operation with 4.8 µm laminations, and T2, designed for 1.5–3 MHz operation with 1.8 µm laminations. Core parameters were optimized using finite-element simulations to meet electrical requirements while maintaining low-profile geometries (~4 mm core thickness). Both transformers were evaluated in customized wide-input LLC converters delivering 5 W (5 V/1 A) isolated dc output, exhibiting stable thermal performance across their respective target frequency ranges. Comparative testing indicates that the resonant LLC topology leads to less core heating than a comparable flyback design, and the thinner laminations in T2 effectively suppress eddy current losses at higher frequencies. These results highlight laminated NiFe as a promising alternative to ferrite cores for compact, high-efficiency MHz-range resonant converters.