
6-26 Power Electronics and Motor Drives
With double-layer winding and Q/t even, or with single-layer windings and Q/(2t), the MMF space
harmonics are only of odd order, so that the harmonic order can be expressed as (2n − 1) times t [40,43].
Conversely, with the other winding combinations, the order of the MMF space harmonics is both
odd and even, so that the harmonic orders are expressed as n times t. Finally, when the double-layer
winding is transformed into a single-layer winding and Q/t is odd (the transformation is possible
only if t is even), the machine periodicity decreases to t/2. Thus, harmonics of lower order (i.e.,
subharmonics) ...