Search

High temperature superconductors (HTS) enable very compact electric machines with high power density. The aim of this paper is to study and improve an HTS power generator based on the authors' previous 10 MW double claw pole design. An additional stator was added to the machine, increasing the copper volume in the generator, resulting in a large increase in power density. Furthermore, with the additional inner stator, the overall current density in the individual stators can be reduced, leading to an increase in efficiency. The modularity of the generator is further improved through the addition of the third stator, further increasing its fault tolerance. The efficiency of the machine can be increased from 94.5% to 95% at a power output of 11.5 MW or through a further reduction of the current density in the stators, an efficiency of 95.6% can be reached while maintaining a power output of 10 MW. Hence, the newly proposed design offers a potential increase in power density, efficiency and modularity while maintaining the same machine diameter and low HTS tape requirements, making the design a very cost‐effective option to enable 10 MW direct‐drive wind turbines. [ABSTRACT FROM AUTHOR]

High-temperature superconducting (HTS) coated conductors (CCs) are widely regarded as a promising candidate to enable very high power density motors. These machines operate at high rotational speeds, with some designs going up to 12 000 rpm. HTS CCs are applied to the field windings of these motors to increase the magnetic loading and hence the power density. Even though the superconducting field windings operate with a DC current, due to the magnetic field environment, losses are present. This paper examines the dynamic and total loss characteristics of YBCO-coated conductors in the frequency range relevant to high-speed motors for electric aircraft propulsion. A multi-layer model was created using the H -formulation and the losses for each layer were highlighted. For the first time, it was shown that the DC transport current region in the HTS layer shrinks as the frequency of the applied field increases due to the increased magnetisation current around the edges of the CC, which reduces the dynamic loss per cycle as the frequency increases. To fully understand the loss distribution in the HTS CC, the total loss in the conductor was investigated. For an applied magnetic field of 100 mT and 800 Hz, more than 30% of the total loss occurs in the copper layer due to the decreased penetration depth of the magnetic field and the skin effect. Results show that to accurately model and understand the losses in superconducting field windings, a multi-layer model should be used, since a significant proportion of loss shifts towards the copper stabilizers. Over all, it was shown that both the dynamic loss as well as magnetisation loss play a crucial role in the estimation of the loss in superconducting field windings. [ABSTRACT FROM AUTHOR]