Increasing of thrust force in transverse flux machine by permanent-magnet screen

This paper proposes a basic model and an analytical study of the transverse flux machines using permanent-magnet (PM) shields to increase the thrust force. By improving the magnetic field distribution in the electrically excited transverse flux linear motor (TFE-LM), the rare-earth PM shields provide an increase of the thrust force. Analytical equations are developed to predict the thrust force and to guide the design of TFE-LM. The thrust force and the thrust force density of TFE-LM with PM shields are calculated also by a 3D-Finite Network Method program. The presence of PM shields in a TFE-LM having a current linkage of 2 kA and the air-gap length of 1 mm leads to the increase of thrust force by approximately 160%. This result reveals a great potential in reducing the mass of the TFE-LM by inserting PM shields in the teeth.