Design and analysis of a Medium Voltage DC wind farm with a transformer-less wind turbine generator

In recent years, the interest in offshore wind farms has been increased significantly. One of the reasons of this development is the less perceived environmental cost of an offshore wind farm with respect to an in-land one, especially for new installations where big turbines are preferred. However, they have also the advantage of an increased and more constant wind speed, leading to higher and more constant production of electrical power. For these kinds of wind farms a pure DC system could be an interesting and cost effective solution. This paper describes an innovative Medium Voltage Direct Current electrical grid system (MVDC) for wind farms, based on transformer-less wind turbines. An accurate analysis is presented and the proposed solution has been validated through a simulation and experimental phase performed on a low voltage prototype.