Siemens SINAMICS DCM Compact User Manual page 12

12-pulse parallel connection
3.1 Topologies
Figure 3-2 12-pulse parallel connection (2), block diagram
Note
If additional converters are connected in parallel to the master converter, then exactly the
same number of converters must also be connected in parallel with the slave converter.
Operation of 12-pulse parallel connection and 6-pulse parallel connection
For the converter topologies as shown in Fig. 3-1 and Fig. 3-2, the following mixed operation
is permissible:
Master side: 4Q unit(s)
Slave side: 2Q unit(s)
This means, in torque direction 1, 12-pulse operation – and in torque direction 2, 6-pulse
operation.
In some special cases, this operating mode is used to address the following requirements:
● Asymmetrical current demand (infeed power is far higher than the regenerative infeed
power)
● A high-speed DC breaker should be used in the armature circuit for fast shutdown in
regenerative operation. This high-speed breaker only has to be dimensioned for
regenerative operation (energy recovery) – and is only necessary for the 4Q units.
Reactor to decouple the partial converters: We recommend that individual reactors are used
instead of an interphase transformer.
Reason: In 6-pulse operation, current only flows through the interphase transformer at one
12
12-pulse applications
Compact User Manual, 09/2015, A5E34871844H