Computational Analysis of Aerodynamic Blade Load Transfer to the Powertrain of a Direct-Drive Multi-MW Wind Turbine

Bichan, Magnus; Jaen-Sola, Pablo; Muhammad Sukki, Firdaus; Sellami, Nazmi

Abstract

This paper details the development of a full turbine model and ensuing aero-servo-elastic analysis of the International Energy Agency’s 15MW Reference Wind Turbine. This model provides the means to obtain realistic turbine performance data, of which normal and tangential blade loads are extracted and applied to a simplified drivetrain model developed expressly to quantify the shaft eccentricities caused by aerodynamic loading, thus determining the impact of aerodynamic loading on the generator structure. During this process, a method to determine main bearing stiffness values is presented, and values for the IEA-15MW-RWT obtained. It was found that wind speeds in the region of turbine cut-out induce shaft eccentricities as high as 56%, and that tangential loading has a significant contribution to shaft eccentricities, increasing deflection at the generator area by as much as 106% at high windspeeds, necessitating its inclusion. During a subsequent generator structure optimisation, the shaft eccentricities caused by the loading scenarios examined in this paper were found to increase the necessary mass of the rotor structure by 40%, to meet the reduced airgap clearance.

Citation

Bichan, M., Jaen-Sola, P., Muhammad Sukki, F., & Sellami, N. (2025). Computational Analysis of Aerodynamic Blade Load Transfer to the Powertrain of a Direct-Drive Multi-MW Wind Turbine. Machines, 13(7), Article 575. https://doi.org/10.3390/machines13070575

• Journal Article Type: Article
• Acceptance Date: Jun 29, 2025
• Online Publication Date: Jul 2, 2025
• Publication Date: 2025
• Deposit Date: Jul 3, 2025
• Publicly Available Date: Jul 3, 2025
• Journal: Machines
• Electronic ISSN: 2075-1702
• Publisher: MDPI
• Peer Reviewed: Peer Reviewed
• Volume: 13
• Issue: 7
• Article Number: 575
• DOI: https://doi.org/10.3390/machines13070575
• Keywords: direct-drive wind turbine; aero-servo-elastic analysis; aerodynamic load transfer; simplified powertrain design; generator structure optimisation