Parallel Connection Of S120 Active Line Modules; Parallel Connection Of S120 Motor Modules - Siemens SINAMICS G130 Engineering Manual

Fundamental Principles and System Description
Engineering Information

Parallel connection of S120 Active Line Modules

The parallel connection of up to four Active Line Modules is supplied by a common two-winding transformer and
controlled by a common Control Unit. This is necessary because the gating impulses for the IGBTs in Active Line
Modules are synchronized by the Control Unit. Thus all Active Line Modules controlled by one Control Unit must be
connected to the same transformer winding with equal phase position. It is not, therefore, admissible to supply this
type of parallel connection by a three-winding transformer with out-of-phase secondary voltages. Since the harmonic
effects on the supply caused by the Active Infeed are only very minor, this type of arrangement would not improve the
conditions in relation to harmonic content.
Parallel connection of S120 Active Line Modules
The following measures help to ensure balanced currents in parallel connections of Active Line Modules:
•
Use of an electronic current sharing control (ΔI control)
•
Reactors in the Clean Power Filters of the Active Interface Modules
•
Use of symmetrical power cabling between the transformer and the parallel-connected Active Interface
Modules / Active Line Modules (cables of identical type with the same cross-section and length)
The current reduction from the rated value for individual Active Interface Modules / Active Line Modules in a parallel
connection is 5 %.

Parallel connection of S120 Motor Modules

Up to four Motor Modules operating in parallel can supply a single motor in vector control mode. The motor can have
electrically isolated winding systems or a common winding system. The type of winding system defines
•
the decoupling measures to be implemented at the outputs of the parallel-connected Motor Modules
•
the modulation systems which may be used to generate the pulse patterns.
In combination with the type of Infeed, the modulation systems determine the magnitude of the maximum attainable
output voltage or the maximum attainable motor voltage (details can be found in sections "Maximum attainable output
voltage with space vector modulation SVM" and "Maximum attainable output voltage with pulse-edge modulation
PEM").
The two possible variants, i.e.
•
motor with electrically isolated winding systems and
•
motor with a common winding system
are discussed in more detail below.
SINAMICS Engineering Manual – May 2008
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