Transformers are widely used in power electronics but their low operating frequency typically makes them bulky. Increasing the switching frequency can significantly reduce transformer size, weight, and production costs, which is particularly advantageous for portable applications such as chargers. This report investigates the operation of high-frequency transformers and presents the design and development of a working prototype operating at up to 3MHz.
Electrical parameters, including inductance, capacitance, and resistance, were measured using a Bode 100 vector network analyser (VNA) and validated through analytical models and finite element simulations in COMSOL Multiphysics. Based on these parameters, a transformer model was constructed using IEEE Std 390 [1] and verified in LTSpice against measured results. Toroidal cores made of soft ferrite materials in various sizes were evaluated, and round copper wire was initially used for windings. To minimize AC resistance at high frequencies, litz wire was selected for the final prototype. The completed transformer was integrated into a switching circuit operating at 1.5MHz, demonstrating successful high-frequency performance and practical viability.