High Frequency Transformer Design and Winding Loss Analysis of Critical Conduction Mode Flyback

The paper gives a complete design and analysis of a 105 W Flyback transformer operating in a critical conduction mode. One of the challenges of CrCM Flyback is the high peak and RMS current that flows in the converter which lead to a higher winding loss in the transformer. Selecting a transformer core and wire size become an important criterion for an efficient operation of the converter. The paper shows a complete loss analysis of the Flyback transformer which includes calculating core loss and copper loss (both AC and DC winding loss). Four transformers were built for the 105 W Flyback prototype and their loss breakdown has been shown.