SENSORLESS FIELD ORIENTED CONTROL OF BRUSHLESS ...

Concentrated Full-Pitch (CFP)
The simplest concentrated winding is the concentrated full-pitch (CFP) winding shown in Figure
C.2. (The span/throw of a coil is the angular distance between the centers of the winding, thus the
largest possible span 180° (though there are exceptions). When the coil span is expressed as a
fraction of 180° is often called the coil pitch. A full-pitch coil thus spans 180° while a 2/3-pitch
coil would span 120°.)
Ideal Sinusoidal
Figure C.2 – Concentrated full-pitch (CFP) winding.
A distributed winding can be formed any number of ways. The only distributed windings of
interest here are the ideal sinusoidal winding (covered in this section) and those that serve to
approximate it (covered in the next section). The sinusoidal winding distribution is defined as
having a density that is a function of the sine of the angle around the rotor. By assuming that each
conductor has negligible diameter the radial thickness of the winding would define the density of
the winding, thus it can be visualized as shown in Figure C.3-a. Since this is impossible to draw
when all three phases are considered the shading is generally not drawn, as shown in Figure C.3b.
The convention used in this report is that a concentrated winding (of any variety) will be
indicated by coilsides in the stator slots (such as in Figure C.2) and a sinusoidal winding will be
indicated by coilsides buried in the stator with no slots shown (such as in Figure C.3-b).
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