Parallel Connections Of Converters; General; Parallel Connections Of Sinamics Converters - Siemens SINAMICS G130 Engineering Manual

Fundamental Principles and System Description
Engineering Information
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Parallel connections of converters

General

It can be useful to connect complete converters and their components (Infeed Modules and Motor Modules) in
parallel for a number of reasons:
•
To increase the converter output power if it is not technically or economically feasible to achieve the
required output power by any other means. For example, it is a relatively complicated procedure to create
parallel connections of large numbers of IGBT modules within the same power unit which means that
using parallel connection of complete power unit s can be the simpler and more cost-effective solution.
•
To increase the availability in cases where it is necessary after a converter malfunction to maintain
emergency operation during which the unit can operate at a lower output than its rated value. In the event
of more or less minor defects within the power unit, for example, it is feasible to deactivate the affected
power unit via the converter control system without shutting down the power unit that are still functional.
The parallel connection strategy for SINAMICS units is essentially designed to increase the converter power output.
The parallel-connected modules (Infeed and Motor Modules) are driven and monitored by a single Control Unit and
are constructed of exactly the same hardware components as the equivalent modules for single drives. All the
functions required for parallel operation are stored in the firmware of the Control Unit. The use of a single shared
Control Unit for the parallel-connected modules and the fact that each fault in any module leads to immediate
shutdown of the entire paralleled system means that a converter parallel connection can be regarded in practical
terms as a single, high-power-output converter.

Parallel connections of SINAMICS converters

SINAMICS converters can be connected in parallel with firmware version V2.3 and higher.
The modular SINAMICS S120 drive system provides the option of operating Infeed Modules and Motor Modules in
parallel on S120 units in the Chassis and Cabinet Modules format. SINAMICS S120 units in Booksize and Blocksize
format cannot be operated in parallel.
S120 Motor Modules can be operated in parallel for vector-type drive objects (vector control), but not for servo-type
drive objects (servo control).
The higher-output G150 cabinets (P ≥ 630 kW for 400 V units, P ≥ 630 kW for 500 V units and P ≥ 1000 kW for 690 V
units) are also designed as a parallel connection based on two lower-output converter cabinets. The details and
special features of the G150 converter parallel connection are described more detailed at the end of the chapter
"Converter Cabinet Units SINAMICS G150".
This section will provide a more detailed description of the basic options for making parallel connections of units of
the SINAMICS S120 modular drive system in Chassis and Cabinet Modules format.
A SINAMICS S120 converter parallel connection consists of:
•
Up to four Infeed Modules (line-side rectifiers) connected in parallel
•
Up to four Motor Modules (motor-side inverters) connected in parallel
•
A single Control Unit which controls and monitors the parallel-connected line and motor-side power units,
so that, in addition to the line and motor-side parallel configuration, no further Motor Modules can be
controlled by the Control Unit.
•
Components on the line and motor side for de-coupling the parallel-connected power units and for
ensuring symmetrical current distribution
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