Double Armature HTS Bulk Synchronous Machine for Contra-Rotating Turbine Generator

Many high-temperature superconducting (HTS) rotors of the radial flux type mainly use the magnetic field from single sided surface of the field pole. However, field poles using HTS bulk have the advantage of capturing high magnetic fields on both sides of the field poles, which can be effectively used to generate electricity. Therefore, we have developed a double armature structure in which a field stator is sandwiched between both the inner and outer armature rotors of the HTS synchronous generator. Due to the high magnetic field captured by the HTS bulk, it is also possible to directly join a counter-rotating turbine. In this paper, we designed the developed model and performed electromagnetic field analysis. The analytical speed was calculated at a low speed depending on the design of the 500kW reverse rotation turbine. Using the HTS bulk as the boundary pole, the torque consistency with the input mechanical torque of the turbine was confirmed, and it was obtained from the compatibility analysis with the 500kW class tidal current power generation. We also analyzed the model with the smallest torque ripple from multiple models with different HTS bulk placements and found the model with the best placement.