Siemens SINAMICS Series Operating Instructions Manual page 616

Descriptions of functions
10.28 Connecting units in parallel and in series
10.28.4 6-pulse series connection: controlled converter + uncontrolled converter
Topology
The following diagram shows the topology of a 6-pulse series connection of a SINAMICS
DCM 2-quadrant unit and a diode rectifier (thyristor bridge B6 + diode rectifier).
Note
The AC input voltage of the controlled converter should be between 10% and 15% higher
than that of the uncontrolled converter, so that the current can be reliably reduced down to 0.
Figure 10-81 6-pulse series connection: controlled + uncontrolled rectifier
The instructions for dimensioning the balancing resistors can be found in an FAQ (for the
link, see the Preface).
614
SINAMICS DCM DC Converter
Operating Instructions, 12/2018, A5E34763375A