Comparative review of disk type and unconventional transverse flux machines: performance analysis

Abstract

Transverse flux machines (TFM) can be designed with high pole numbers, so they are very useful in directdrive systems with high torque density. Although many TFM models have been proposed to date, no detailed classification and comparison has been made before. Conventional TFMs have a high power and torque density, but low power factors and high cogging torques have prevented them from being widely used. However, especially with the new disk type TFMs proposed in recent years and the methods developed, these drawbacks have been reduced. In this paper, the TFMs proposed in recent years have been classified and their performances in terms of power factor, cogging torque, torque density, and efficiency have been examined. According to the results of this review, the performances of the new generation TFMs are competitive. Especially double-sided disk type TFMs are seen as an important topology with their high magnet utilization and flexibility in design.

A Review of Transverse Flux Machines Topologies and Design

“…According to the literature [14][15][16][17][18][19][20], TFMs were first introduced in 1895 by W. M. Morday, but they gained wider attention towards the end of the 20th century from the studies of Laithwaite et al [21], and Weh and May [22]. Figure 2a shows one pole pair of a basic TFM: a ring-shaped coil is embraced by stator U-cores that guide the magnetic flux from one permanent magnet (PM) to another.…”

“…In Table 2, a comparison of TFMs found in the literature is shown, regarding the stator core and three basic performance indexes: torque density, efficiency and power factor. Another comparison can be found in [20], based on the machine ratings instead of the TFM topology. Notes: CP: claw-pole, SM: surface-mounted.…”