6 folier pr. side - NTNU
6 folier pr. side - NTNU
6 folier pr. side - NTNU
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<strong>NTNU</strong><br />
<strong>NTNU</strong><br />
<strong>NTNU</strong><br />
Slide 385<br />
us<br />
Slide 387<br />
Slide 389<br />
Utledning av ekvivalentskjemaer<br />
■ Stasjonære forhold:<br />
u s = rs<br />
⋅ is<br />
+ � ⋅ f s ⋅ ψ s<br />
0 = rr<br />
⋅ i r + �⋅<br />
f r ⋅ ψ r<br />
f r = f s − n<br />
m e =<br />
T ( is<br />
) � ψ s<br />
■ Flukser og magnetiseringsstrøm:<br />
k k k<br />
iμ<br />
= is<br />
+ i r<br />
x s = x h + x sσ<br />
ψ = x s ⋅ is<br />
+ x h ⋅ i r = x s i s x h i<br />
s<br />
σ ⋅ + ⋅ μ<br />
ψ r = x h ⋅ i s + x r ⋅ i r = x rσ<br />
⋅ i r + x h ⋅ i μ<br />
ψ = x s s ⋅ is<br />
+ x h ⋅ i r<br />
ψ = x r h ⋅ is<br />
+ x r ⋅ i r<br />
x r = x h + x rσ<br />
Ekvivalentskjema basert på rotorfluks<br />
■ Spenningsbalanser:<br />
x h<br />
u s = ( rs<br />
+ �⋅<br />
f s ⋅ x σ ) ⋅ i s + � ⋅ f s ⋅ ⋅ i<br />
1 + σ<br />
f s rr<br />
x h<br />
0 =<br />
⋅ ( 1+<br />
σ r ) ⋅ i<br />
2<br />
r + �⋅<br />
fs<br />
⋅ ⋅ iμr<br />
f ( 1 + σ )<br />
1+<br />
σ<br />
r<br />
�� σ � �� �<br />
r<br />
�<br />
μr<br />
r<br />
is ( 1 + σr<br />
) ⋅ ir<br />
r<br />
Trondheim 2000<br />
��<br />
�� �<br />
1+ σ<br />
iμr<br />
u μr<br />
� �<br />
�<br />
�<br />
� = ⋅<br />
��<br />
2<br />
( 1+<br />
σ ) �<br />
�<br />
�<br />
Konstant statorfluks<br />
■ Sammenheng spenning, frekvens og fluks:<br />
u s = rs<br />
⋅ i s + � ⋅ f s ⋅ ψ ≈ � ⋅ f s s ⋅ ψ s<br />
■ Klassisk styring av fluks<br />
2<br />
⎛ rs<br />
⎞ 2<br />
u s = ψ s ⎜ + f s ≈ ψ s ⋅ f s<br />
x ⎟<br />
⎝ s ⎠<br />
■ Moment ble styrt med statorfrekvens:<br />
f r s<br />
= f − n<br />
2<br />
1 f r ⋅ ωn<br />
⋅ Tr<br />
⎛ x h ⎞<br />
’<br />
me = ⋅<br />
⋅ 2<br />
s Tr<br />
x<br />
’ ⎜ ⋅ ψ<br />
= σ ⋅<br />
r 1 ( f r n Tr<br />
) x ⎟<br />
+ ⋅ ω ⋅ ⎝ s ⎠<br />
Trondheim 2000<br />
T<br />
r<br />
Trondheim 2000<br />
<strong>NTNU</strong><br />
<strong>NTNU</strong><br />
<strong>NTNU</strong><br />
us<br />
Slide 386<br />
us<br />
Slide 388<br />
Slide 390<br />
Utledning av ekvivalentskjemaer…..<br />
■ Setter inn spenningslikingene:<br />
u = ( r + � ⋅ f ⋅ x ) ⋅ is<br />
+ � ⋅ f ⋅ x ⋅ i<br />
s<br />
s<br />
s<br />
sσ<br />
⎛ f s<br />
⎞<br />
0 = ⎜ rr<br />
+ �⋅<br />
f s ⋅ x rσ<br />
⎟ ⋅ i r + � ⋅ f s ⋅ x h ⋅ iμ<br />
⎝ f r<br />
⎠<br />
�� � �σ<br />
�<br />
�� is<br />
s<br />
h<br />
� � � ��<br />
μ<br />
i<br />
ir<br />
μ<br />
� �σ<br />
� ��<br />
Ekvivalentskjema basert på rotorfluks<br />
■ Definisjoner og sammenhenger:<br />
u<br />
ψ<br />
r<br />
μr<br />
= � ⋅ f s = �<br />
1 + σr<br />
ψr<br />
α<br />
�� σ � �� �<br />
ψr<br />
β<br />
x<br />
⋅ fs<br />
1+<br />
h<br />
σ r<br />
is ( 1 + σr<br />
) ⋅ ir<br />
�<br />
⋅ i<br />
k<br />
μr<br />
is = i r is<br />
= ( 1 + σ r ) ⋅ i r<br />
μ<br />
�<br />
� ⋅ �<br />
�<br />
�<br />
�<br />
Trondheim 2000<br />
��<br />
�� �<br />
1+ σ<br />
iμr<br />
u μr<br />
� �<br />
�<br />
�<br />
� = ⋅<br />
��<br />
2<br />
( 1+<br />
σ ) �<br />
�<br />
�<br />
Konstant U/f<br />
■ Sammenheng spenning, frekvens og fluks:<br />
u = � ⋅ f ⋅ ψ ⇒ u = ψ ⋅ f<br />
1<br />
f rk =<br />
’<br />
ωn<br />
⋅ Tr<br />
2<br />
1 ⎛ x h ⎞<br />
m e,<br />
max = ⋅<br />
s<br />
2 x ⎜ ⋅ ψ<br />
r x ⎟<br />
⋅ σ ⋅ ⎝ s ⎠<br />
s<br />
s<br />
s<br />
3<br />
2<br />
1<br />
0<br />
-1<br />
-2<br />
s<br />
s<br />
-3<br />
0 0.5 1 1.5 2<br />
s<br />
Fra venstre:<br />
f s ,u s = 0.2<br />
f s ,u s = 0.4<br />
f s ,u s = 0.6<br />
f s ,u s = 0.8<br />
f s ,u s = 1.0<br />
f s =1.2, u s = 1.0<br />
f s =1.4, u s = 1.0<br />
f s =1.6, u s = 1.0<br />
Trondheim 2000<br />
Trondheim 2000