Operating Modes - Siemens SINAMICS Series Operating Instructions Manual

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Table of Contents

Descriptions of functions

10.28 Connecting units in parallel and in series

Figure 10-80 6-pulse series connection (2)

The instructions for dimensioning the balancing resistors can be found in an FAQ (for the

link, see the Preface).

Operating modes

There are 2 operating modes:

● Operation with the same firing pulses (p51799 = 0 or p51799 = 31):

Both partial converters are fired at precisely the same point. The master calculates the

firing point and this is transferred to the slave via the parallel interface. Synchronization to

the line supply is exclusively performed by the master. The slave must be connected to

the line supply with the same phase sequence as the master.

● Operation with sequence control (p51799 = 32):

Both partial converters synchronize to the line supply and generate their own firing points.

The firing angle for the master and the firing angle for the slave are calculated by the

master and the firing angle and the torque direction for the slave are transferred to the

slave via the parallel interface. The firing angle for the master and slave are generated so

that the reactive power load of the line supply is as low as possible. This is the case if

one of the two partial converters is at a control limit and the other carries-out the closed-

loop control. This type of closed-loop control is only possible for continuous current.

Operation with the same firing points is automatically selected in the discontinuous

(pulsating) current range.

The phase sequence at the master and the slave must be the same.

SINAMICS DCM DC Converter

Operating Instructions, 12/2018, A5E34763375A