Comparative Study of 1-MW PM and HTS Synchronous Generators for Marine Current Turbine

Thanks to the high predictability and energy density of marine current, it can be utilized to generate electricity in an environmental and efficient form. However, placing a large-scale marine current turbine system is challenging, which requires a proper drive-train system to achieve high efficiency. In this paper, a conceptual structure of direct-driven marine current turbine generator (MCTG) is proposed. Then, the electromagnetic design method is developed, including the specifications, design, and optimization procedures. Two generator topologies using permanent magnets (PMs) and high temperature superconducting (HTS) windings in field poles are adopted for comparison. Design results demonstrate that it is feasible to design a 1-MW MCTG with HTS field winding at 77 K for the proposed structure. Furthermore, the optimum number of poles is found near 66 and 32 for PM and HTS topologies, respectively. Finally, it is found that the weight and efficiency for MCTG is around 17 ton, 89.6 % for the PM topology and 16 ton, 91.9 % for the HTS topology.