SENSORLESS FIELD ORIENTED CONTROL OF BRUSHLESS ...

3
Lmag L
2
3
Lmag L
2
3
Lmag L
2
(B.17)
It is seen that the “effective inductance” seen by each phase is larger than the self inductance of
that phase and is called the synchronous inductance LS.
3
LS Lmag L (B.18)
2
The synchronous inductance is therefore a result of the fundamental airgap flux produced by one
winding, the fundamental airgap flux produced by current in the other two windings, and the
leakage flux [69], [75], [28]. This is roughly symbolized by Figure B.2 and Figure B.3, which
again emphasize that leakage and airgap components exist in the self inductance but the mutual
inductance is due to the airgap component alone. Figure B.3 emphasizes that the reluctance paths
are the same for the magnetizing and mutual components are the same (because we neglect the
reluctance of the steel). The only difference is the displacement in coil axes, hence Equation
(B.16).
Figure B.2 – Relationship of inductances for phase-A.
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