Multi-level medium voltage converter

The project ” Multi-level medium voltage” converter is a development and demonstration project, which by proposing at new design aims at optimizing one of the most important subsystems in a wind turbine. It is an collaboration between research and industry companies and will boost creation of both engineering and production jobs in the sector.
Cost efficiency gains are considered necessary to maintain public and political support for large-scale implementation of offshore wind and to maintain the competitive edge of Danish actors in the market. A critical component in a wind turbine (WTG) is the power converter, which basic function in a wind turbine is converting a varying voltage/frequency from the generator into a fixed voltage/frequency output synchronized to the power grid.
As WTG´s become larger, the power converter also increases in sizes causing an increased focus on the size, weight, efficiency, reliability and price.
The most common type is the low voltage converter, and increasing turbine power has been accompanied by adding more low voltage systems in parallel. However, there is a pull from many of the WTG manufactures for the introduction of medium voltage (MV) converters. The MV components are generally more expensive than low voltage components triggering the objective of the project to build a MV converter based on the less expensive low voltage components- By stacking of low voltage system in series rather than parallel, a MV converter can be build, using LV components. Thus, the proposed multi-level medium voltage converter system will bring the benefit from both systems.