The EU-funded EcoSwing project addresses the world's first full-scale direct-drive (DD) high temperature superconducting (HTS) wind turbine generator. Before the generator was installed on a commercial wind turbine, the generator had been tested on the ground at the Dynamic Nacelle Testing Laboratory (DyNaLab) in Fraunhofer Institute for Wind Energy Systems (IWES), serving as an experimental validation of the generator design. This article is centered on the ground testing of the EcoSwing HTS generator, which includes corresponding tests for validating the generator's cryogenic design and electromagnetic performance. Despite one HTS coil with a defect limiting the operating current significantly, partial power production up to 1 MW at 14.5 rpm was reached. The critical auxiliary systems, i.e., vacuum system and rotary helium coupling, behaved as expected or even better than anticipated. The work reported in the article successfully validates the generator design, and also provides firsthand information prior to installing and testing the HTS generator on the wind turbine.

High temperature superconducting (HTS) generators could enable a lightweight and cost-effective direct drive (DD) wind turbines with large power ratings. The EU-funded EcoSwing project successfully demonstrated the world's first full-scale MW-class HTS generator on a commercial DD wind turbine. This paper focuses on the commissioning of the EcoSwing HTS generator on the wind turbine. The commissioning campaigns, including the rotor cool-down, excitation of the HTS field winding, and the power production of the generator, are presented in the paper. In the testing period, the generator was grid-connected for more than 650 hours and accumulatively produced more than 600 MWh to the grid. The target output power of the 3 MW class was reached. Throughout the real-life testing on the wind turbine, the generator performed well from the electromagnetic, thermal, and mechanical perspectives. Moreover, the generator even sustained three sudden short circuits in the converter system. The work reported has shown that HTS generators are technologically feasible for wind turbine applications, and the technology readiness level of HTS wind turbine generators has been improved to 6~7 for the first time.

The main aim of the EU H2020 project EcoSwing was to demonstrate a technical readiness level of 6-7 for high-temperature superconducting (HTS) technology operating in a wind generator. To reach this goal, a full-scale synchronous HTS generator was successfully designed, built and field-tested in a 3.6 MW turbine. The generator has a rotor with 40 superconducting coils of 1.4 m long. The required >20 km of coated conductor was produced within the project's time schedule. All coils were tested prior to assembly, with >90% of them behaving as expected. The technical readiness level of HTS coils was thus increased to level 7. Simultaneously, the maturing of cryogenic cooling technology over the last decade was illustrated by the several Gifford-McMahon cold-heads that were installed on-board the rotor and connected with the stationary compressors through a rotating coupling. The cryogenic system outperformed design expectations, enabling stable coil temperatures far below the design temperature of 30 K after only 14 d of cool-down. After ground-based testing at the IWES facility in Bremerhaven, Germany, the generator was installed on an existing turbine in Thyboron, Denmark. Here, the generator reached the target power range and produced power for over 650 h of grid operation.

High temperature superconducting (HTS) technologies are expected to be a key enabler for lightweight and cost-effective direct-drive (DD) trains for large wind turbines. This paper reports the designing and basic experimental validation of the worlds first full-scale DD HTS generator demonstrated on a commercial wind turbine. The HTS generator has its rotor with an HTS field winding working below 30K, which is achieved by using off-the-shelf Gifford-McMahon cryocoolers. The stator of the generator is essentially conventional, except that the armature winding has four segments to limit fault torques in case of sudden short circuits due to converter failures. Compared to an existing DD permanent magnet generator on the turbine, the air gap shearing stress of the HTS generator is doubled, and the weight is reduced by 24. The overall design requirements from the turbine integration perspective, as well as the topological considerations, are first described in this paper. The electromagnetic and cryogenic designs are then presented, followed by performance testing of HTS coils. The basic experimental validation shows that the cryogenic design is satisfactory and the measured no-load voltage matches the finite element calculation very well.