Research towards large scale superconducting wind generators

• Applicant: Professor Dr.-Ing. Mathias Noe
• Subject Area: Electrical Energy Systems, Power Management, Power Electronics, Electrical Machines and Drives
• Term: from 2018 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 392069063

Since the strong demand for clean energy, the wind market keeps sustained and rapid growth during the last ten years, and the offshore wind energy has been the main growth point due to large resource space and relatively stable wind power. Hence, the offshore wind industry is attracting more and more attention. There is a clear trend for offshore wind industry that the large power, more than 10MW, direct drive wind generators are preferred to reduce the cost/MW at their full life circles. However, the large power direct drive wind generators require large torque demand, and this leads to heavy weight and huge volume. Therefore, the development of high torque density electrical machines become urgently needed for the large scale offshore wind generator.Among many high torque density electrical machines, superconducting machines are believed to be one of the best candidates for the large scale offshore wind turbines with the advantages of much higher torque density, higher efficiency.In this project, a comprehensive study on the machine topologies, including AC or DC generators, rotating armature windings or rotating field windings, iron cores or air cored, fully superconducting or hybrid superconducting machine, are done to choose the most suitable structure for the large scale offshore wind generators. The large scale wind generator introduces complicate environment, such as high magnetic-force and magnetic fields at both health and fault conditions, for superconducting coils, and all of this are special and harsh for superconducting materials. Hence, the research on material properties and superconducting coils during health and fault conditions will be one of the key point in this project and a multi-field coupling analytical model of the material will be built to help researcher to analyze the material performance (iron and HTS) and reliability at complicated field environment. Then, superconducting machine design and material researches will be synchronous. The whole electromagnetic,mechanical,thermal and refrigeration structure design procedure will be given, and the multi-objective optimization including maximizing torque density, minimizing superconducting consumption of the superconducting machine will be done. Furthermore, since the electric port features such as high electromotive force and smaller reactance of the superconducting generators, the fault current may be very large, and this introduce big challenge for both superconducting coils, generator and convertor. The port features, including current, voltage and torque, and electric-magnetic-stress field will be carefully analyzed, the research on high reliability design and auxiliary protection method of the HTS coils and generator will be given.The project will develop a number of key innovations enabling the superconducting generator for wind application for electricity and the success of it will lead to remarkable technological, environmental and societal benefits.

• DFG Programme: Research Grants
• International Connection: China
• Partner Organisation: National Natural Science Foundation of China
• Cooperation Partners: Dr. Dawei Li; Professor Dr. Ronghai Qu
• Co-Investigator: Professor Dr.-Ing. Martin Doppelbauer