A transformerless generator-converter concept making feasible a 100 kV low weight offshore wind turbine Part II - The converter

A transformerless wind power generator concept with the potential to achieve 100 kV DC output is introduced in this work. The work is presented in two papers. Part I: The Generator, describes the electrical machine properties of the special, 10 MW generator. This part, Part II, presents a modular AC/DC-converter system suitable for this wind turbine drive train solution. A conceptual description of the system is given and the synthesis of the control system is presented. The control system robustness against parameter- and operating point variations is studied through frequency domain analysis. The theoretical studies are supported by simulations of the full system in EMTDC/PSCAD. The results from both the analysis and simulations show good performance for the wind turbine system.