27.02.2013 Views

an investigation of dual stator winding induction machines

an investigation of dual stator winding induction machines

an investigation of dual stator winding induction machines

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

where, ω s1<br />

<strong>an</strong>d s2<br />

respectively.<br />

ω are the slip frequency <strong>of</strong> ABC <strong>winding</strong> <strong>an</strong>d XYZ <strong>winding</strong><br />

Substituting (2.5) into (2.3), the magnetic load c<strong>an</strong> be found. The results show that the<br />

value <strong>of</strong> the magnetic load obtained by this method is independent <strong>of</strong> the pole numbers<br />

combination <strong>an</strong>d <strong>of</strong>fset <strong>an</strong>gles, except one special case-- p = , p = 4 [2.2]. The<br />

49<br />

1<br />

2 2<br />

magnetic load calculated by the proposed method is close to the second approach <strong>an</strong>d the<br />

adv<strong>an</strong>tages <strong>an</strong>d disadv<strong>an</strong>tages <strong>of</strong> these two methods have been addressed in the paper.<br />

However, all the methods that have been mentioned c<strong>an</strong> only be used to evaluate the<br />

combined magnetic load <strong>an</strong>d c<strong>an</strong> not be used to determine the magnetic load <strong>of</strong> the <strong>stator</strong><br />

<strong>winding</strong> sets.<br />

It should be noted that once the <strong>stator</strong> <strong>winding</strong> sets are fixed in the <strong>stator</strong>, the<br />

mech<strong>an</strong>ical <strong>an</strong>gle between these two <strong>stator</strong> <strong>winding</strong> sets c<strong>an</strong> not ch<strong>an</strong>ge <strong>an</strong>y more.<br />

However, the electrical <strong>an</strong>gle between the voltage vectors <strong>an</strong>d the current vectors <strong>of</strong> two<br />

<strong>stator</strong> <strong>winding</strong> sets are variable <strong>an</strong>d controllable. Then it c<strong>an</strong> be found that at some<br />

particular load conditions, the peak value that claim to occur relatively infrequently in<br />

[2.2] c<strong>an</strong> always be found at that kind <strong>of</strong> load. Hence it is better to consider the worst<br />

operating case in the design <strong>of</strong> the <strong>dual</strong> <strong>stator</strong> <strong>winding</strong> machine.<br />

A straightforward method that c<strong>an</strong> be used to design the magnetic load <strong>of</strong> each <strong>stator</strong><br />

<strong>winding</strong> has been discussed in [1.11]. To avoid deep saturation <strong>of</strong> the core material, the<br />

peak magnetic loading produced by the combined effect <strong>of</strong> the two MMFs must be the<br />

same as that <strong>of</strong> <strong>an</strong> equivalent single <strong>stator</strong> <strong>winding</strong> design, which me<strong>an</strong>s the peak flux<br />

density in the air gap must remain const<strong>an</strong>t <strong>an</strong>d the maximum flux density per pole must<br />

be identical in both the <strong>dual</strong> <strong>stator</strong> <strong>an</strong>d single <strong>stator</strong> design. Since dissimilar pole numbers

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!