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 205<br />
Slide 207<br />
Transferfunksjonsmodell av motor og<br />
omformer<br />
Transferfunksjoner for strøm og turtall<br />
Trondheim 2000<br />
i f<br />
u dio<br />
ra<br />
⋅ ( 1 + Ta<br />
⋅ s)<br />
n(<br />
s)<br />
=<br />
⋅ ⋅ u st ( s)<br />
−<br />
⋅ m ( s)<br />
2<br />
2 L<br />
ra<br />
⋅ Tm<br />
⋅ s ⋅ ( 1 + Ta<br />
⋅ s)<br />
+ i f 1 + Tv<br />
⋅ s ra<br />
⋅ Tm<br />
⋅ s ⋅ ( 1 + Ta<br />
⋅ s)<br />
+ i f<br />
Tm<br />
⋅ s<br />
u dio<br />
if<br />
i a ( s)<br />
=<br />
⋅ ⋅ u st ( s)<br />
+<br />
⋅ m L ( s)<br />
2<br />
2<br />
r T s ( 1 T s)<br />
i 1 + Tv<br />
⋅ s<br />
a ⋅ m ⋅ ⋅ + a ⋅ + f<br />
ra<br />
⋅ Tm<br />
⋅ s ⋅ ( 1 + Ta<br />
⋅ s)<br />
+ if<br />
Slide 209<br />
2<br />
1.5<br />
1<br />
0.5<br />
0<br />
-0.5<br />
-1<br />
-1.5<br />
Momentkarakteristikker for uregulert<br />
maskin<br />
m e=f(n)<br />
-2<br />
-2 0 2 4 6<br />
Trondheim 2000<br />
■ De stasjonære karakteristikker:<br />
u a − i f ⋅ n<br />
i a =<br />
ra<br />
2<br />
i f ⋅ u a − i f ⋅ n<br />
m e =<br />
ra<br />
m e = i f ⋅ i a = m L<br />
■ Sterk følsomhet i strøm og<br />
moment ved endring av<br />
turtall<br />
■ Redusert følsomhet i<br />
feltsvekkingsområdet<br />
Trondheim 2000<br />
<strong>NTNU</strong><br />
<strong>NTNU</strong><br />
<strong>NTNU</strong><br />
Slide 206<br />
Slide 208<br />
Slide 210<br />
Modell med konstant feltstrøm<br />
−sTv<br />
u dio<br />
−sT<br />
i f ⋅ n(<br />
s)<br />
u dio ⋅ e ⋅ u st ( s)<br />
− i f ⋅ n(<br />
s)<br />
v<br />
i a ( s)<br />
=<br />
⋅ e ⋅ u st ( s)<br />
−<br />
=<br />
ra<br />
⋅ ( 1 + Ta<br />
⋅ s)<br />
ra<br />
⋅ ( 1 + Ta<br />
⋅ s)<br />
ra<br />
⋅ ( 1 + Ta<br />
⋅ s)<br />
ra= 0.09 Ta=12 ms Tm=0.1 s<br />
i f = 0<br />
1<br />
0.8<br />
0.6<br />
0.4<br />
0.2<br />
0<br />
-0 .2<br />
-0 .4<br />
-0 .6<br />
-0 .8<br />
-1<br />
① 1/2*T<br />
a<br />
① i = 1<br />
f<br />
① i f = 1<br />
Plassering av polene<br />
Im<br />
i f = 0<br />
Re<br />
if<br />
ω0<br />
=<br />
raTa<br />
Tm<br />
1<br />
α = ζ ⋅ ω0<br />
=<br />
2Ta<br />
Trondheim 2000<br />
■ Polene til systemet er gitt<br />
av:<br />
2<br />
N ( s)<br />
= ra<br />
⋅ Tm<br />
⋅ s ⋅ ( 1 + Ta<br />
⋅ s)<br />
+ i f<br />
■ Polene blir da:<br />
1 ⎡<br />
⎤<br />
2 Ta<br />
s1,<br />
2 = ⎢−<br />
1±<br />
1 − ( 2 ⋅ i f ) ⋅ ⎥<br />
2 ⋅ Ta<br />
⎢⎣<br />
ra<br />
⋅ Tm<br />
⎥⎦<br />
■ Dempning og resonansfrekvenser:<br />
1 raTm<br />
ζ =<br />
2 i f Ta<br />
Momentkarakteristikker for<br />
strømregulert maskin<br />
m e=f(n) i a=f(n)<br />
-2 -1 0 1 2<br />
2<br />
2 i f 1<br />
ω = 1-<br />
ζ ⋅ ω0<br />
= − 2<br />
raTa<br />
Tm<br />
4Ta<br />
Trondheim 2000<br />
■ De stasjonære karakteristikker:<br />
u a = rai<br />
a + n ⋅ i f<br />
u a,<br />
max − ra<br />
⋅ i a<br />
i f =<br />
n<br />
m e = i f ⋅ i a = m L<br />
■ Moment <strong>pr</strong>oporsjonal med<br />
ankerstrøm i nedre<br />
turtallsområde<br />
■ Feltstrøm redusert ~1/n i<br />
feltsvekkingsområdet<br />
Trondheim 2000