Using an AC line reactor with a DC choke
In this configuration, the 20 hp, 480 V, 60 Hz drive with its internal 4.3% impedance DC choke uses an additional external AC line reactor. Figure 14 shows that using an additional AC line reactor from 0 up to 5% impedance reduces:
-
THDi from 43.0% down to 28.5% when using 5% line reactor
-
The 5th harmonic from 33.5% to 26.2% of the fundamental
-
The 7th harmonic from 21.9% to 8.1% of the fundamental
Using an AC line reactor with a DC choke
The total DC bus voltage drop and the input current THDi are shown in Figure 15.
Total DC bus voltage drop and input current THDi
The total voltage drop starts at 0% impedance of the additional AC line reactor, with the value obtained with the internal DC choke only. It goes up to 7% with a 5% impedance of the additional AC line reactor. At the same time, the input current THDi is reduced from 43% down to 28.5%. For comparison, the input current THDi is also displayed.
A 3% impedance AC line reactor brings about 10% additional input current THDi reduction compared to what is reached with the 5% DC choke, with almost 2% additional voltage drop in the DC bus.
Performance Overview
An AC line reactor used in combination with a DC choke brings an additional reduction of the input current THDi, mainly by reduction of the 7th harmonic for which the AC line reactor was already better than the DC choke when either is used alone. This leads to an additional voltage drop on the DC bus. Using the 3% impedance AC line reactor from the MTE catalog in association with the ATV630 / ATV930 drives range gives the data shown in the table below. A 4.3% choke or a 3% line reactor provide effective harmonic mitigation. After these values, the addition of AC reactance begins to have diminishing returns at the expense of voltage drop.
|
ATV630•••N4 |
U07 |
U15 |
U22 |
U40 |
U55 |
U75 |
D11 |
D15 |
D18 |
D22 |
D30 |
|
Power rating (hp) |
1 |
2 |
3 |
5 |
7.5 |
10 |
15 |
20 |
25 |
30 |
40 |
|
+ MTE 3% AC line reactor (reference) |
RL-00201 |
RL-00402 |
RL-00803 |
RL-00802 |
RL-01202 |
RL-01802 |
RL-02502 |
RL-03502 |
RL-03502 |
RL-04502 |
RL-05502 |
|
Line reactor current rating (A) |
2 |
4 |
8 |
8 |
12 |
18 |
25 |
35 |
35 |
45 |
55 |
|
AC line reactor inductance (mH) |
12.0 |
6.5 |
5.0 |
3.0 |
2.5 |
1.5 |
1.2 |
0.8 |
0.8 |
0.7 |
0.5 |
|
Line reactor impedance (%) |
1.9 |
2.0 |
2.2 |
2.2 |
2.7 |
2.1 |
2.5 |
2.2 |
2.8 |
2.9 |
2.7 |
|
Total impedance (%) |
5.2 |
5.4 |
5.8 |
5.5 |
6.3 |
6.3 |
7.3 |
6.5 |
6.9 |
7.0 |
6.9 |
|
THDi (%) |
35.4 |
35.0 |
34.2 |
34.9 |
33.0 |
33.5 |
31.9 |
33.1 |
32.2 |
32.0 |
32.1 |
|
Voltage drop (%) |
5.3 |
4.9 |
4.5 |
5.0 |
4.6 |
4.8 |
5.4 |
5.1 |
5.6 |
5.6 |
5.4 |
|
ATV630•••N4 |
D37 |
D45 |
D55 |
D75 |
D90 |
C11 |
C13 |
C16 |
C22 |
C25 |
C31 |
|
Power rating (hp) |
50 |
60 |
75 |
100 |
125 |
150 |
200 |
250 |
350 |
400 |
500 |
|
+ MTE 3% AC line reactor (reference) |
RL-08002 |
RL-10002 |
RL-10002 |
RL-13002 |
RL-16002 |
RL-20002B14 |
RL-25002B14 |
RL-32002B14 |
RL-50002 |
RL-50002 |
RL-60002 |
|
Line reactor current rating (A) |
80 |
100 |
100 |
130 |
160 |
200 |
250 |
320 |
500 |
500 |
600 |
|
AC line reactor inductance (mH) |
0.4 |
0.3 |
0.3 |
0.2 |
0.15 |
0.11 |
0.09 |
0.075 |
0.05 |
0.05 |
0.04 |
|
Line reactor impedance (%) |
2.7 |
3.3 |
3.1 |
2.7 |
2.5 |
2.2 |
2.4 |
2.5 |
2.3 |
2.7 |
2.7 |
|
Total impedance (%) |
6.7 |
7.3 |
6.8 |
6.9 |
6.3 |
5.4 |
6.6 |
7.7 |
7.3 |
7.7 |
7.3 |
|
THDi (%) |
32.4 |
31.3 |
31.9 |
32.1 |
32.9 |
34.5 |
32.3 |
31.0 |
31.2 |
30.4 |
30.4 |
|
Voltage drop (%) |
5.5 |
5.5 |
5.8 |
5.4 |
5.2 |
4.9 |
4.4 |
4.4 |
4.4 |
3.5 |
3.5 |