Active and Structural Mass and Cost Comparison of 20 MW Direct-Drive Generators for Horizontal-Axis Offshore Wind Turbines
IEEE Access, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Basım Tarihi: 2026
- Doi Numarası: 10.1109/access.2026.3732012
- Dergi Adı: IEEE Access
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Compendex, INSPEC, Directory of Open Access Journals
- Anahtar Kelimeler: CpF, generator, MpF, Wind turbine
- Orta Doğu Teknik Üniversitesi Adresli: Evet
Özet
Electric machines are manufactured in a wide range of configurations and power ratings to meet diverse application requirements, with performance commonly evaluated in terms of durability, mass, cost, and efficiency. However, direct comparison is challenging due to fluctuations in material costs driven by temporal and geographical factors, as well as variations in machine speed, torque and diameter. To address these limitations, this study introduces the active mass-per-shear force (MpF) and active cost-per-shear force (CpF) ratios as robust metrics for electric machine comparison. A comparative analysis is performed for 20 MW generators operating at rotational speeds of 7, 8, and 9 rpm and with varying air-gap diameters of 5-10 m. The generator technologies considered include C-GEN, pseudo direct-drive (PDD), permanent magnet generators (PMG), electrically excited claw-pole Vernier machines (EECPV), fully superconducting generators using EuBCO (FSC-EuBCO) and MgB2 (FSC-MgB2), as well as partially superconducting generators using MgB2 (PSC-MgB2). The active, structural, and total masses, together with the associated costs, are evaluated and compared. While C-GEN machines feature the most lightweight design, EECPV machines exhibit the lowest metarial cost. Although iron-cored fully (FSC-EuBCO) superconducting machines possess the lowest active mass, the high magnetic flux density within the air gap significantly increases their structural mass. This study provides a comparative assessment confined strictly to the material costs of the generators. To determine the economic viability of a specific generator type, a comprehensive analysis beyond material procurement, which contains manufacturing, transportation and operation and maintenance (O&M) expenses, is essential. Furthermore, future studies should quantify the sensitivity of total wind turbine structural costs to generator mass reduction, as this interaction remains a critical factor in system-level cost-effectiveness.The data derived from this study may serve as a baseline to guide future investigations in this area.