ABSTRACT
Transverse flux PMSMs were apparently introduced in 1986 in an effort to increase torque density in low and medium variable-speed motors by separating the magnetic and electric circuit design and thus reducing the pole pitch τ PM down to 10–20 mm even in large torque applications. The I-shaped cores between U-lamination stator cores allow for all magnets to be active all the time in a flux line with four airgap crossings. The IPM rotor allows for PM flux concentration, that is, higher torque density. The I-shaped core advantage is paid for in a larger leakage inductance of the machine. The main problem is PM flux fringing, while the main advantage is torque magnification by increasing the number of poles 2p PM. Double-sided stator configurations, especially with IPMs, are favorable in reducing PM flux fringing by making all the magnets active all the time and increasing torque/volume.
