Affiliations: [a] Lappeenranta University of Technology, Lappeenranta,
Finland | [b] Tallinn University of Technology, Tallinn,
Estonia | [c] Visedo Oy, Tuotantokatu, Lappeenranta, Finland
Correspondence:
[*]
Corresponding author: Pia Lindh, Lappeenranta University of
Technology, PL 20, 53850 Lappeenranta, Finland. Tel.: +358 400 152 420; Fax:
+358 5621 7199; E-mail: Pia.lindh@lut.fi
Abstract: Permanent magnet (PM) machines with tooth coil windings are designed
and analyzed. We study how the slot wedge material affects the behavior of PM
losses when using tooth coil windings, which generate a significant air gap
flux density harmonic content. The losses and cogging torques of a surface
permanent magnet rotor and an interior permanent magnet rotor are compared in
no-load and load situations. A finite element analysis applying Cedrat's Flux2D
is made. Motors of this size can have high permanent magnet eddy current
losses, and therefore, segmented magnets are often preferred even though
interior magnets and semi-magnetic wedge material are used. The study shows
that tooth coil windings may benefit from using semi magnetic material as a
wedge material as it decreases the stator iron losses and, especially, losses
in the permanent magnets.
