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SENSORLESS FIELD ORIENTED CONTROL OF BRUSHLESS ...

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xA<br />

X1cos( t) X3cos(3 t) X5cos(5<br />

t)<br />

<br />

xB<br />

X1cos( t) X3cos(3 t) X5cos(5 t) <br />

xC<br />

X1cos( t) X3cos(3 t) X5cos(5 t) 1 jt1 jt1 j3t1 j3t Xe 1 Xe 1 Xe 3 Xe 3<br />

2 2 2 2 <br />

x<br />

A <br />

1 j5t 1 j5t Xe 5 Xe<br />

<br />

<br />

5<br />

2 2<br />

<br />

<br />

1 j( t) 1 j( t) 1 j(3 t) 1 j(3 t)<br />

<br />

Xe 1 Xe 1 Xe 3 Xe<br />

3<br />

x<br />

2 2 2 2 <br />

B <br />

1 j(5 t) 1 j(5 t) Xe 5 Xe<br />

<br />

5<br />

2 2<br />

<br />

<br />

1 j( t) 1 j( t) 1 j(3 t) 1 j(3 t)<br />

<br />

Xe 1 Xe 1 Xe 3 Xe 3<br />

<br />

x<br />

2 2<br />

C <br />

2 2 <br />

<br />

1 j(5 t) 1 j(5 t) Xe 5 Xe<br />

<br />

5<br />

2 2<br />

<br />

2<br />

jj x xA1xBe xC e<br />

<br />

3 <br />

<br />

jt jt j3t j3t j5t j5t Xe 1 Xe 1 Xe 3 Xe 3 Xe 5 Xe 5 <br />

1 jt j( t) j(3 t) j(3 t) j(5 t) j5t <br />

x X1e X1e X3e X3e X5e X5e <br />

3<br />

<br />

Xe Xe Xe Xe Xe Xe<br />

<br />

jt j( t) j(3 t) j(3 t) j(5 t) j5t 1 1 3 3 5<br />

5<br />

<br />

<br />

PS 0 ZS 0<br />

0<br />

0<br />

NS <br />

<br />

x X e X e<br />

jt j5t 1 5<br />

(D.34)<br />

(D.35)<br />

(D.36)<br />

(D.37)<br />

(D.38)<br />

Equation (D.37) has six vertical columns indicated by brackets. The terms in the three columns<br />

marked “0” are often encountered when SV equations are simplified by hand and they sum to<br />

zero. For each such column there is normally a corresponding column (marked PS, ZS, and NS)<br />

that does not sum to zero. However in this case it is clear that the ZS column does sum to zero.<br />

Equation (D.38) demonstrates that the SV contains the PS and NS components present in the<br />

phase variables but does not contain the ZS component. Given that the SV is of dimension two it<br />

simply cannot contain all of the information in x abc (which is of dimension three) unless 0<br />

is true (in which case x abc can always be rewritten as dimension two). This does not mean that<br />

some quantity q of dimension two can never contain common-mode components; the basis of q<br />

could be defined such that it does. What is instead true is that the MSC and SV transforms are<br />

325

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