Topology and Technology Survey on Medium Voltage Power Converters for Large Wind Turbines

Based on state-of-the-art within generator and power converter designs, this paper presents and justifies the most promising converter circuitries and concepts for future 10 MW wind turbines. In order to reduce losses and increase efficiency of the turbine, it is assumed that the bulky step-up transformer is permanently removed from the topology. As a result, the generator-converter circuitry operates on 20 kV level, which introduces new challenges into the design. The first part of the paper presents a system approach, in which general converter features are discussed with regard to this specific application. Based on obtained conclusions, the second part of the paper highlights the most promising converter topology concepts and circuitries, which can be adapted and eventually utilized. Finally, results show that the most promising topologies can be acquired from a modular approach, which is made by various circuit configurations of previously defined power modules.