SENSORLESS FIELD ORIENTED CONTROL OF BRUSHLESS ...

Figure 3.46 – Simulation diagram for BPMS motor in stationary reference frame.
The stationary model is essentially the same as the phase-variable model, less one phase. Since
the SV (or αβ components) cannot contain a ZS component, it is clear that a wye-connected
machine is modeled exactly as shown (since we do not have independent control of the third
phase). This elimination of the redundant phase (and the orthogonalization of the coordinates) is
the chief advantage of the stationary model, just as these were the chief advantages of using the
SV. In addition, it was shown that the SV can be easily manipulated since it is a complex
exponential. The additional benefit of the SV model (over the αβ model) then is that the
(electrical or magnetic) quantities are all space vectors instead of components. This can be drawn
as Figure 3.47, where the double lines indicate SV quantities. The applied voltage is shown as
broken out into is αβ components (this idea was taken from [166]). There is no difference
between this and the former model except it clearly emphasizes the SV as an entity (as opposed to
treating its components separately).
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