User Manual

7
Current harmonic spectrum comparison up to the 13th fundamental
In tests between a conventional 6-pulse VSD and the SED2, note how
the SED2 demonstrates superior, lower harmonic results at the 5th
and 7th fundamental.
O
5O
10O
15O
-5O
-10O
-15O
Current (%)
Time
0
2
4
6
8
10
12
14
16
5791113
Current (%)
Harmonic order
No filtering More than 120% with 3% line reactor with 5% line reactor with DC link choke
SED2 VFD
0
10
20
30
40
50
60
70
80
90
100
THDI (%)
Typical 6-pulse VSD
Typical scenario
Current waveform of a typical 6-pulse VSD vs. the SED2
At the input terminal of a 6-pulse VSD, THD can be in excess of 120 % without any filtering (i.e. AC line reactors or DC link chokes).
The SED2 produces only 29 % THD.
Total harmonic distortion reduction comparison
In tests between a typical 6-pulse VSD with and without AC line
reactors and DC link chokes versus the SED2, the Siemens Easy Drive
demonstrates superior harmonic performance. In typical HVAC ap-
plications, the SED2 can reduce harmonics by up to 25 % more than
other VSDs even with AC line reactors or DC link chokes.
■ SED2 6-pulse VSD
■ Typical 6-pulse VSD