IGBTs (fundamental frequency-switched) serve as Smart Line Module power semiconductors. As this reduces switching losses, a high percentage of the power unit current can be utilized.

The current flows in the direction of the infeed via the freewheeling diodes of the IGBTs. This means that the Smart Line Module behaves in a similar way to the Basic Line Module. If the DC link voltage increases due to regenerative operation of the drives, the IGBTs conduct the current, thus feeding the energy back into the supply system.

In contrast to Active Line Modules, Smart Line Modules do not require a line-side filter; all they require is a line reactor (4 % u_k). The unit has a built-in pre-charging circuit for the DC link capacitors. For this reason, a main contactor or a motor-driven circuit breaker is absolutely essential. By specifying the option with order code L44 for the Line Connection Modules, these components are appropriately accommodated in the Line Connection Module.

Parallel connection of Smart Line Modules to increase power rating

Up to four Smart Line Modules with the same power rating can be connected in parallel in order to increase power. Current derating of 7.5% with respect to the rated current of each Smart Line Module must be taken into account when the system is dimensioned.

A connection of the Smart Line Modules connected in parallel using DRIVE‑CLiQ must be taken into consideration during the engineering phase.

For additional information, please refer to the SINAMICS Low Voltage Engineering Manual.

A 4% reactor is always required upstream of each Smart Line Module for the purpose of current symmetrization. This is integrated as standard. Just as with the Basic Line Modules, "mirror-image" power connections are available for Smart Line Modules, which enable parallel circuits to be realized in a compact design. Units that are arranged to the left of the Line Connection Module have the letter "C" in the penultimate position of the article number.
Example: 6SL3730‑6TE41‑1BC3 (see also the corresponding diagram for the Basic Line Modules).