Offshore wind farm with DC collection system

This paper sets forth a novel dc-based topology utilizing series-connected permanent-magnet synchronous generators for offshore wind farms, as an alternative to the common ac topology. The system's design, namely, the individual wind turbine power electronics, the collection system topology, and the overall system control is presented. An efficiency analysis suggests that the proposed dc topology leads to energy savings due to the reduced number and different type of energy conversion stages, as well as a variable-voltage control strategy. The stability and operation of the multi-branch topology are briefly discussed.