Analytical Model and Concept Study of an Air Gap Fringing Shield to Reduce Losses in Gapped Inductors

The impact of the magnetic fringing field emanating from the air gap in gapped inductors on the high-frequency losses has been known for a while. While most research focuses on accurately calculating these losses, attempts to reduce them through suitable measures are rare. This article investigates a concept that uses a fringing field shield to attenuate the fringing field at higher frequencies, thereby reducing losses in the winding. With this approach, losses in the shield itself occur, but the overall winding losses are reduced by 24% for an inductor subjected to a current waveform with a mixed harmonic spectrum and a dominant low-frequency component. The concept is proven using a manufactured prototype.