Effect of Air Gap Thickness on Transverse-Flux Permanent Magnet ( TFPM ) Machines with Flux-Concentration

The use of Transverse-Flux Permanent Magnet (TFPM) machines for high-torque and low-speed application is investigated. The ability of TFPM structures with fluxconcentration to reduce the cost of active material is looked upon more closely. The Cost/Torque characteristics of TFPM (Transverse-Flux Permanent Magnet) machines and Conventional Permanent Magnet Synchronous machines are presented. It is emphasized how the air gap thickness plays a dominant role in the cost savings provided by the TFPM structure. For air gap of 0.5 mm, the TFPM structure with flux concentration discussed in the paper shows important cost benefits, over the Conventional Permanent Magnet Synchronous machine. Above the 3.5 mm threshold, the TFPM with flux concentration does not show such great cost advantages over the Conventional Permanent Magnet Synchronous machine.