Danfoss AHF 010, Руководство по конструкции

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frequency converter installations often show that the
performance of the filter is slightly better with a 2%
background distortion. However, the complexity of the grid
conditions and the mix of specific harmonics does not
provide a general rule about the performance on a
distorted grid.
Illustration 3.3 and Illustration 3.4 show
worst-case performance deterioration characteristics with
the background distortion.
0 20 40 60 80 100
0
5
10
15
20
25
THvD 0%
THvD 2%
THvD 5%
Load [%]
TH
iD a
ver
age [%]
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Illustration 3.3 AHF 005
0
10
20
30
40
50
60
0 20 40 60 80 100
Load [%]
THvD 0%
THvD 2%
THvD 5%
THiD [%]
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Illustration 3.4 AHF 010
Performance at 10% THDv has not been plotted. However,
the filters have been tested and can operate at 10% THDv,
but the filter performance can no longer be guaranteed.
The filter performance also deteriorates with the unbalance
of the supply. Typical performance is shown in
Illustration 3.5 and Illustration 3.6 .
0% unbalance
1% unbalance
2% unbalance
3% unbalance
0 20 40 60 80 100
Load [%]
0
2
4
6
8
10
12
14
TH
iD [%]
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Illustration 3.5 AHF 005
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0
0 20 40 60 80 100
Load [%]
5
10
15
20
25
0% unbalance
1% unbalance
2% unbalance
3% unbalance
THiD average [%]
Illustration 3.6 AHF 010
3.1.1 Power Factor
In no-load conditions (the frequency converter is in stand-
by), the frequency converter current is negligible, and the
main current drawn from the grid is the current through
the capacitors in the harmonic filter. Therefore, the power
factor is close to 0, capacitive. The capacitive current is
approximately 25% of the filter nominal current (depends
on filter size, typical values of 20–25%). The power factor
increases with the load. Because of the higher value of the
main inductor L
0
in the VLT
®
Advanced Harmonic Filter
AHF 005, the power factor is slightly higher than in the
VLT
®
Advanced Harmonic Filter AHF 010.
Illustration 3.7 and Illustration 3.8 show typical values for
the true power factor on AHF 010 and AHF 005.
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
1
0 20 40 60 80 100
Load [%]
True P
ow
er F
ac
tor
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Illustration 3.7 AHF 005
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
1
0 20 40 60 80 100
Load [%]
0
True Power Factor
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Illustration 3.8 AHF 010
Basic Operating Principle o...
VLT
®
Advanced Harmonic Filter AHF 005/AHF 010
16 Danfoss A/S © 05/2019 All rights reserved. MG80C602
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