High-temperature superconducting (HTS) materials

with their zero-resistance properties

are ideal for use as excitation coils in the rotors of offshore wind turbine motors

enhancing power density and efficiency. However

since superconductors require cryogenic operation

the AC losses in HTS coils impact the cooling system design and overall machine efficiency. To address this issue

a novel method for calculating AC losses in HTS coils based on the T-A formulation is proposed

which divides the HTS coil into multiple regions to simplify the computational model and improve convergence. Validation results demonstrate that the proposed method achieves accurate calculations with significantly improved processing time. Through comparative studies of different motor structures

it is found that

when ferromagnetic stator teeth are employed

the iron-core rotor structure can reduce AC losses by over 70% compared to an air-core rotor. Further analysis reveals that the number of coil turns and the distance from the ferromagnetic teeth to the coil are two decisive factors influencing the losses. This research provides valuable insights for accurately calculating AC losses in rotor coils of HTS synchronous generators and

to some extent

offers guidance for the selection of superconducting motors and the design of superconducting coils.