Siemens SINAMICS DCM Manual page 562

10.27 Connecting units in parallel and in series
Topology overview
Several SINAMICS DCM converters can be arranged in various topologies. The following
topologies are supported:
● 6-pulse parallel connection
This topology is used in order to realize converter power ratings that are above the
highest available SINAMICS DCM rating.
● 12-pulse parallel connection
This topology is especially used at higher power ratings to achieve lower line harmonics.
In addition, by using this circuit, a lower DC current ripple is obtained when compared to
a 6-pulse connection. One or several 6-pulse converters can be connected in parallel to
each of the two 12-pulse converters connected in parallel.
● 6-pulse series connection
This topology is used to achieve a higher no-load DC voltage.
The following versions are available:
– Both converters are operated with the same firing angle.
– Sequence control (one of the two converters is always at a control limit, the other
– Series connection of a controlled converter with an uncontrolled converter (thyristor
One or several converters can be connected in parallel to each of the converters
connected in series to increase the power rating.
● 12-pulse series connection
The topology corresponds to a 6-pulse series connection. In addition, a lower DC current
ripple is obtained when compared to a 6-pulse connection. One or several converters can
be connected in parallel to each of the converters connected in series to increase the
power rating.
Note
• All of the topologies listed here are only permissible in the restricted line frequency range
from 20 Hz to 65 Hz.
• For all of the topologies listed here, only devices with the same DC current rating may be
used.
• For all of the topologies listed here, only devices with the same software version may be
used.
Note
More information about design is given in the associated application notes (see link in
preface).
SINAMICS DCM DC Converter
Operating Instructions, 02.2015, A5E34763375/RS-AA/001
converter controls the armature current)
bridge B2 + diode rectifier)
ac.maher.co.ir
Descriptions of functions
10.27 Connecting units in parallel and in series
563