CONTINUUM DYNAMICS INC — Department of Energy SBIR Phase I: 19a

Description

The economic viability of wind energy is critically dependent upon robust, long-duration operation, while minimizing outages and costs for repair and ongoing maintenance. Active load mitigation offers a way to control fatigue-inducing loads so as to forestall major failures, preclude costly repairs and service interruptions, and extend the life of wind turbine blades, generator components and the entire turbine system. Mitigation of loads requires some form of adaptation of the turbine to variable conditions e.g., atmospheric turbulence, wind speed variation, turbine to turbine interaction, tower shadow), and these needs can be addressed through an application of smart materials-based devices to provide on-blade aerodynamic control. Use of low profile control surfaces actuated via Shape Memory Alloy SMA) mechanisms would allow localized aerodynamic load inputs from a simple, robust and cost-effective modification, thereby allowing the direct control of impulsive and fatigue life-limiting oscillatory loads. The actuator design proposed here embodies a low-power implementation that is well suited to integration with newly constructed blades and potentially for retrofit onto existing systems. The projected cost of this class of devices is well within the parameters identified in the literature as being consistent with real-world installations. The work to be proposed would perform initial development of this load control system, which would leverage both lessons learned from prior implementation of on-blade control surfaces for wind turbines and rotorcraft as well as major elements of condition monitoring methods developed for air vehicle applications. The projected technical objectives for the Phase I effort would be to: 1) establish tradeoffs between actuator response speed/cycles and turbine blade lifespan/fatigue loads; 2) establish actuator and device scaling; 3) estimate device lifespan based on actuation response and projections of operational loads and resilience to damage; and 4) develop a provisional manufacturing/blade integration plan. The team would include actuation device design, scaling, and cycle life analysis expertise from Continuum Dynamics, Inc., along with overall project technical direction; critical support on identifying designs that could maximize blade life extension would be provided by Sandia National Laboratories; and guidance both from Sandia and TPI Composites regarding requirements and methods for integration the projected actuators into practical blade designs. The Phase I proof of concept effort would lay the foundation for both demonstration integration efforts on turbine blades as well as larger scale testing in Phase II. The principal immediate application of this work is to provide additional control mechanisms to improve the reliability and life of wind turbine blades and systems. The actuator and adaptive control system technology to be developed as part of this effort could be used for new turbine designs and also be applied to retrofit existing wind energy systems for improved performance and structural life. The principal immediate application of this work is to provide additional control mechanisms to improve the efficiency and reliability of wind turbine rotors and wind turbine systems. The actuator and adaptive control system technology to be developed as part of this effort could be used for new turbine designs and also be applied to retrofit existing wind energy systems for improved performance and structural life. The net effect of their use would support reducing the operating costs of wind turbines, thereby improving their power conversion capability and enhancing their power quality.