Environmental Engineering Reference
In-Depth Information
S
4
N
4
t
p
1
3
5
7
9
11
13
15
17
19
21
23
25
slot #
N
16
S
16
t
p
,1
Figure 5.49 PPM winding connection for 4-pole (top) and 16-pole (bottom)
operation
Figure 5.50 Flux patterns of PPM machine for toroidal IM: (a) 2-pole flux
pattern of PPM and (b) 12-pole flux pattern of PPM
9-phase machine is considered to be three sets of 3-phase machines, a single sensor per
set will suffice provided the proper voltage control is applied to the remaining 2 phases
per set. One technique being investigated is to augment the three physical current
sensors with machine flux sensors in the remaining 6 phases.
5.4.3.4 Pole changing PM
Several years ago, there was work performed on what was termed a 'written' pole
machine in which the permanent magnet rotor was re-magnetized periodically via
the stator into a new set of permanent magnet poles. This was done in order to
realize frequency control from a prime mover that was less regulated than would
otherwise be necessary.
