The Low Loss Concept (LLC) is a power distribution system comprising higher efficiency, lower weight and volume, and a high system redundancy. The basic motive for the design is to reduce and eliminate the need for supply (pulse) transformers to the frequency converters, especially those supplying electric propulsion.
LLC is available for both Low Voltage and Medium Voltage applications. It covers all power applications between 5MW and 45MW in both the Low Voltage and Medium Voltage versions. It is effective also in vessels with operating profiles that require variable speeds, such as OSVs.
The LLC power distribution system has been patented internationally by the Wärtsilä Group.
The LLC solution is based on a common 30 degrees phase shifting transformer, which provides the power supply to the 12 pulse rectifying bridge, thus cancelling harmonic currents caused by the frequency converters.
Example Schema SLD LLC