Title: Integrated design of downwind land‐based wind turbines using analytic gradients

Abstract

Abstract Wind turbines are complex systems where component‐level changes can have significant system‐level effects. Effective wind turbine optimization generally requires an integrated analysis approach with a large number of design variables. Optimizing across large variable sets is orders of magnitude more efficient with gradient‐based methods as compared with gradient‐free method, particularly when using exact gradients. We have developed a wind turbine analysis set of over 100 components where 90% of the models provide numerically exact gradients through symbolic differentiation, automatic differentiation, and adjoint methods. This framework is applied to a specific design study focused on downwind land‐based wind turbines. Downwind machines are of potential interest for large wind turbines where the blades are often constrained by the stiffness required to prevent a tower strike. The mass of these rotor blades may be reduced by utilizing a downwind configuration where the constraints on tower strike are less restrictive. The large turbines of this study range in power rating from 5–7MW and in diameter from 105m to 175m. The changes in blade mass and power production have important effects on the rest of the system, and thus the nacelle and tower systems are also optimized. For high‐speed wind sites, downwind configurations domore » not appear advantageous. The decrease in blade mass (10%) is offset by increases in tower mass caused by the bending moment from the rotor‐nacelle‐assembly. For low‐wind speed sites, the decrease in blade mass is more significant (25–30%) and shows potential for modest decreases in overall cost of energy (around 1–2%). Copyright © 2016 John Wiley & Sons, Ltd.« less

Authors:

Ning, Andrew ^[1]; Petch, Derek ^[2]

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+ Show Author Affiliations

1. Brigham Young University Provo 84602 Utah USA
2. National Renewable Energy Laboratory Golden 80401 Colorado USA

Publication Date:

Fri Feb 19 00:00:00 EST 2016

Sponsoring Org.:

USDOE

OSTI Identifier:

1400738

Grant/Contract Number:  

DE‐AC36‐08GO28308

Resource Type:

Publisher's Accepted Manuscript

Journal Name:

Wind Energy

Additional Journal Information:

Journal Name: Wind Energy Journal Volume: 19 Journal Issue: 12; Journal ID: ISSN 1095-4244

Publisher:

Wiley Blackwell (John Wiley & Sons)

Country of Publication:

United Kingdom

Language:

English