Mw. Degner et al., A ROTOR LAMINATION DESIGN FOR SURFACE PERMANENT-MAGNET RETENTION AT HIGH SPEEDS, IEEE transactions on industry applications, 32(2), 1996, pp. 380-385
A major problem in the design and manufacturing of surface mounted per
manent magnet machines is reliably holding the permanent magnets in pl
ace at high speeds. This paper evaluates a unique rotor lamination des
ign for a high pole number, permanent magnet alternator. This buried m
agnet design, which is capable of reliably holding the permanent magne
ts in place at high speeds, offers both easier and cheaper assembly wh
en compared with the methods currently used in surface mounted permane
nt magnet machines, Finite element analysis is used to compare the bur
ied magnet design with equivalent surface mounted designs and shows th
at the performance of the alternator is not significantly affected by
the iron over the magnets. Experimental results from a prototype alter
nator further corroborate the FEA acid show that the design is capable
of operating at high speeds with no other means of magnet retention.
In addition, an improvement in the buried magnet design which can redu
ce the lamination complexity is suggested and examined.