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 307<br />
Slide 309<br />
Slide 311<br />
PM maskin med overflate monterte magneter<br />
■ I feltsvekking må man kjøre en negativ d-komponent av<br />
strømmen får å få redusert feltet:<br />
u = �⋅<br />
n ⋅ ψ<br />
ψ = x ⋅ i + ψ<br />
s<br />
ψ = x ⋅ i + ψ<br />
d<br />
e<br />
s<br />
m<br />
d<br />
m = ψ ⋅ i<br />
s<br />
q<br />
m<br />
s<br />
ψ = x ⋅ i<br />
■ Man får da mindre q-komponent til å lage moment:<br />
2<br />
s,<br />
max<br />
2<br />
d<br />
2<br />
q<br />
q<br />
2<br />
q<br />
s<br />
s<br />
s<br />
2<br />
s,<br />
max<br />
i = i + i ⇒ i = i − i<br />
Man ønsker størst mulig q-komponent av statorstrømmen tatt<br />
hensyn til begrensninger i maskimal tillatt statorstrøm og<br />
maksimal tilgjengelig statorspenning<br />
1<br />
0.8<br />
0.6<br />
0.4<br />
0.2<br />
q<br />
2<br />
d<br />
Maksimalt tilgjengelig moment<br />
0<br />
0 0.5 1 1.5 2 2.5 3<br />
n<br />
ψ s<br />
m e<br />
m<br />
x s = 0.3-0.35 pu<br />
Trondheim 2000<br />
Trondheim 2000<br />
De optimale d- og q-komponenter for en gitt i s<br />
■ Den optimale q-komponent (maks moment <strong>pr</strong>. ampere):<br />
2 2<br />
2 2<br />
m e = ψ m ⋅ i q - (x q - x d ) ⋅ i d ⋅ i q = ψ m ⋅ i q + (x q - x d ) ⋅ i s − i q ⋅ i q hvor i d = − is<br />
− i q<br />
2 2<br />
∂m<br />
i s − 2 ⋅ i<br />
e<br />
q<br />
= ψ m + (x q - x d ) ⋅ = 0<br />
∂i<br />
2 2<br />
q<br />
i s − i q<br />
2<br />
1.8<br />
1.6<br />
1.4<br />
1.2<br />
1<br />
0.8<br />
0.6<br />
0.4<br />
0.2<br />
⇒<br />
0<br />
-1 -0.8 -0.6 -0.4 -0.2 0<br />
2 ψ m ⋅ i d<br />
i q = ± i d −<br />
x q − x d<br />
Trondheim 2000<br />
<strong>NTNU</strong><br />
<strong>NTNU</strong><br />
<strong>NTNU</strong><br />
Slide 308<br />
Slide 310<br />
Slide 312<br />
Maksimal tillatt q-strøm<br />
2 2 2<br />
i s,<br />
max = id<br />
+ i q ⇒<br />
2 2 2<br />
i q = i s,<br />
max − id<br />
2 2 2<br />
u s,<br />
max = n ⋅ ψ s ⇒<br />
⎛ u s, max<br />
⎜<br />
⎝ n<br />
2<br />
2<br />
⎛ u s, max ⎞ 2 2<br />
2 2 2 2 2<br />
⎜ ⎟<br />
⎜<br />
x s i d 2 x s i d m m x s is,<br />
max x s i d<br />
n ⎟<br />
= ⋅ + ⋅ ⋅ ⋅ ψ + ψ + ⋅ − ⋅<br />
⎝ ⎠<br />
2 2 2<br />
= 2 ⋅ x s ⋅ i d ⋅ ψ m + ψ m + x s ⋅ i s, max<br />
2<br />
u<br />
2 2 2 ⎛ s, max ⎞<br />
ψ m + x s ⋅ is,<br />
max −<br />
⎜<br />
n ⎟<br />
i d = −<br />
⎝ ⎠<br />
2 ⋅ x s ⋅ ψ m<br />
i q,<br />
max =<br />
2<br />
2<br />
⎛ u<br />
⎞<br />
⎜ ⎛ s, max ⎞ 2 2 2<br />
⎜ ⎟ − ψ m − x s ⋅ i ⎟<br />
s, max<br />
⎜ ⎜ n ⎟<br />
⎟<br />
2<br />
is,<br />
max ⎜<br />
⎝ ⎠<br />
−<br />
⎟<br />
⎜ 2 ⋅ x s ⋅ ψ m ⎟<br />
⎜<br />
⎟<br />
⎝<br />
⎠<br />
me<br />
, max = ψ m ⋅ i q,<br />
max<br />
⎞<br />
2 2<br />
⎟ = ( x s ⋅ i d + ψ m ) + x s ⋅ i<br />
⎠<br />
PM maskin med indre monterte magneter IPMSM<br />
■ x q > x d gir også et reluktansmoment:<br />
u d = −n<br />
⋅ ψ q<br />
u q = n ⋅ ψ d i d = −i<br />
s ⋅ sin( δ − ϕ)<br />
ψ d = x d ⋅ i d + ψ m ψ q = x q ⋅ iq<br />
i q = is<br />
⋅ cos( δ − ϕ)<br />
x q − x d 2<br />
m e = ψ m ⋅ iq<br />
− ( x q − x d ) ⋅ id<br />
⋅ i q = ψ m ⋅ is<br />
⋅ cos( δ − ϕ)<br />
+ ⋅ is<br />
⋅ sin 2(<br />
δ − ϕ)<br />
2<br />
■ Ønsker fortsatt mest<br />
moment <strong>pr</strong>. ampere<br />
■ Må ha negativ dkomponent<br />
av<br />
0.2<br />
0<br />
i =0.4<br />
s<br />
i =0.2<br />
s<br />
strømmen<br />
-0.2<br />
■ Men denne bidrar<br />
-0.4<br />
ϕp også med moment !!! -80 -60 -40 -20 0 20 40 60 80<br />
❙ s<br />
Statorfluksens avhengighet av i s<br />
ψ<br />
=<br />
2<br />
1.8<br />
1.6<br />
1.4<br />
1.2<br />
1<br />
0.8<br />
0.6<br />
0.4<br />
0.2<br />
s<br />
0<br />
0 0.2 0.4 0.6 0.8<br />
i<br />
s<br />
1 1.2 1.4 1.6<br />
1.2<br />
1<br />
0.8<br />
0.6<br />
0.4<br />
( ) ( ) 2<br />
2<br />
ψ + x ⋅ i + x ⋅ i<br />
m<br />
d<br />
d<br />
q<br />
q<br />
i s =1.0<br />
i s =0.8<br />
i s =0.6<br />
2<br />
q<br />
Trondheim 2000<br />
Trondheim 2000<br />
Trondheim 2000