Efficient Networks Siemens Sinamics S120 - Manual (Page 46)

Infeed
1.7 Parallel connections of 6-pulse and 12-pulse chassis infeeds
Drive Functions
46
Function Manual, (FH1), 07/2007 Edition, 6SL3097-2AB00-0BP4
1.7 Parallel connections of 6-pulse and 12-pulse chassis infeeds
Description
With Basic Line Modules and chassis units, in addition to 6-pulse parallel infeed (infeed via
two-winding transformer), it is also possible to use a 12-pulse parallel infeed (infeed via
three-winding transformer).
6-pulse parallel infeeds (two-winding transformer)
For the parallel operation of 6-pulse infeeds, a common Control Unit should always be used
for Basic Line Modules and Smart Line Modules.
For Basic Line Modules, a second, separate Control Unit may be used if redundancy is
desired.
12-pulse parallel infeeds (three-winding transformer)
For 12-pulse parallel infeeds via Smart Line Modules, separate Control Units must be
provided for each infeed due to the 30° phase offset between the two converter systems.
Parallel operation of two 12-pulse infeeds, controlled by a single Control Unit, is possible
with Basic Line Modules. If redundancy is desired, a second, separate Control Unit can be
used.
When separate Control Units are used, pre-charging may not be synchronized accurately
enough, i.e. a converter system must be able to pre-charge the total capacity of the drive
line-up. Pre-charging power for the DC link in parallel operation must be dimensioned so that
the capacity of the DC link can be fully charged by a single converter system. Otherwise a
separate pre-charging device must be provided.
L1, L2, L3 L1, L2, L3
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Figure 1-11 Parallel infeeds for 6-pulse and 12-pulse operation