Balancing Power Absorption and Fatigue Loads in Irregular Waves for an Oscillating Surge Wave Energy Converter
Abstract
The aim of this paper is to describe how to control the powertoload ratio of a novel wave energy converter (WEC) in irregular waves. The novel WEC that is being developed at the National Renewable Energy Laboratory combines an oscillating surge wave energy converter (OSWEC) with control surfaces as part of the structure; however, this work only considers one fixed geometric configuration. This work extends the optimal control problem so as to not solely maximize the timeaveraged power, but to also consider the powertakeoff (PTO) torque and foundation forces that arise because of WEC motion. The objective function of the controller will include competing terms that force the controller to balance power capture with structural loading. Separate penalty weights were placed on the surgefoundation force and PTO torque magnitude, which allows the controller to be tuned to emphasize either power absorption or load shedding. Results of this study found that, with proper selection of penalty weights, gains in timeaveraged power would exceed the gains in structural loading while minimizing the reactive power requirement.
 Authors:
 Publication Date:
 Research Org.:
 National Renewable Energy Lab. (NREL), Golden, CO (United States)
 Sponsoring Org.:
 USDOE Office of Energy Efficiency and Renewable Energy (EERE), NREL Laboratory Directed Research and Development (LDRD)
 OSTI Identifier:
 1335573
 Report Number(s):
 NREL/CP500067559
 DOE Contract Number:
 AC3608GO28308
 Resource Type:
 Conference
 Resource Relation:
 Conference: Presented at the ASME 2016 35th International Conference on Ocean, Offshore and Arctic Engineering, 1924 June 2016, Busan, South Korea
 Country of Publication:
 United States
 Language:
 English
 Subject:
 16 TIDAL AND WAVE POWER; wave energy converter; WEC; oscillating surge wave energy converter; OSWEC; power takeoff; NREL
Citation Formats
Tom, Nathan M., Yu, YiHsiang, Wright, Alan D., and Lawson, Michael. Balancing Power Absorption and Fatigue Loads in Irregular Waves for an Oscillating Surge Wave Energy Converter. United States: N. p., 2016.
Web. doi:10.1115/OMAE201655046.
Tom, Nathan M., Yu, YiHsiang, Wright, Alan D., & Lawson, Michael. Balancing Power Absorption and Fatigue Loads in Irregular Waves for an Oscillating Surge Wave Energy Converter. United States. doi:10.1115/OMAE201655046.
Tom, Nathan M., Yu, YiHsiang, Wright, Alan D., and Lawson, Michael. Fri .
"Balancing Power Absorption and Fatigue Loads in Irregular Waves for an Oscillating Surge Wave Energy Converter". United States.
doi:10.1115/OMAE201655046.
@article{osti_1335573,
title = {Balancing Power Absorption and Fatigue Loads in Irregular Waves for an Oscillating Surge Wave Energy Converter},
author = {Tom, Nathan M. and Yu, YiHsiang and Wright, Alan D. and Lawson, Michael},
abstractNote = {The aim of this paper is to describe how to control the powertoload ratio of a novel wave energy converter (WEC) in irregular waves. The novel WEC that is being developed at the National Renewable Energy Laboratory combines an oscillating surge wave energy converter (OSWEC) with control surfaces as part of the structure; however, this work only considers one fixed geometric configuration. This work extends the optimal control problem so as to not solely maximize the timeaveraged power, but to also consider the powertakeoff (PTO) torque and foundation forces that arise because of WEC motion. The objective function of the controller will include competing terms that force the controller to balance power capture with structural loading. Separate penalty weights were placed on the surgefoundation force and PTO torque magnitude, which allows the controller to be tuned to emphasize either power absorption or load shedding. Results of this study found that, with proper selection of penalty weights, gains in timeaveraged power would exceed the gains in structural loading while minimizing the reactive power requirement.},
doi = {10.1115/OMAE201655046},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Jun 24 00:00:00 EDT 2016},
month = {Fri Jun 24 00:00:00 EDT 2016}
}

The aim of this paper is to describe how to control the powertoload ratio of a novel wave energy converter (WEC) in irregular waves. The novel WEC that is being developed at the National Renewable Energy Laboratory combines an oscillating surge wave energy converter (OSWEC) with control surfaces as part of the structure; however, this work only considers one fixed geometric configuration. This work extends the optimal control problem so as to not solely maximize the timeaveraged power, but to also consider the powertakeoff (PTO) torque and foundation forces that arise because of WEC motion. The objective function of themore »

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