Limits...
Stochastic control of inertial sea wave energy converter.

Raffero M, Martini M, Passione B, Mattiazzo G, Giorcelli E, Bracco G - ScientificWorldJournal (2015)

Bottom Line: The response of the WEC (wave energy converter) is driven by the sea-surface elevation, which is modeled by a stationary and homogeneous zero mean Gaussian stochastic process.System equations are linearized thus simplifying the numerical model of the device.Results of this approach have been compared with the ones obtained with a linear spring-damper controller, highlighting the capability to obtain a higher value of mean extracted power despite higher power peaks.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanics and Aerospace Engineering, Polytechnic University of Turin, Corso Duca degli Abruzzi 24, 10129 Turin, Italy.

ABSTRACT
The ISWEC (inertial sea wave energy converter) is presented, its control problems are stated, and an optimal control strategy is introduced. As the aim of the device is energy conversion, the mean absorbed power by ISWEC is calculated for a plane 2D irregular sea state. The response of the WEC (wave energy converter) is driven by the sea-surface elevation, which is modeled by a stationary and homogeneous zero mean Gaussian stochastic process. System equations are linearized thus simplifying the numerical model of the device. The resulting response is obtained as the output of the coupled mechanic-hydrodynamic model of the device. A stochastic suboptimal controller, derived from optimal control theory, is defined and applied to ISWEC. Results of this approach have been compared with the ones obtained with a linear spring-damper controller, highlighting the capability to obtain a higher value of mean extracted power despite higher power peaks.

No MeSH data available.


Time histories of the main system variables. (a) Wave excitation force versus pitch speed and (b) PTO torque and power.
© Copyright Policy - open-access
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4385674&req=5

fig4: Time histories of the main system variables. (a) Wave excitation force versus pitch speed and (b) PTO torque and power.

Mentions: From Figure 4, it can be noticed that the power flux between the PTO and the gyroscope is bidirectional (i.e., the PTO sometimes acts as a motor), therefore introducing a reactive power component. This is why this kind of control is also referred to as “reactive control.”


Stochastic control of inertial sea wave energy converter.

Raffero M, Martini M, Passione B, Mattiazzo G, Giorcelli E, Bracco G - ScientificWorldJournal (2015)

Time histories of the main system variables. (a) Wave excitation force versus pitch speed and (b) PTO torque and power.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4385674&req=5

fig4: Time histories of the main system variables. (a) Wave excitation force versus pitch speed and (b) PTO torque and power.
Mentions: From Figure 4, it can be noticed that the power flux between the PTO and the gyroscope is bidirectional (i.e., the PTO sometimes acts as a motor), therefore introducing a reactive power component. This is why this kind of control is also referred to as “reactive control.”

Bottom Line: The response of the WEC (wave energy converter) is driven by the sea-surface elevation, which is modeled by a stationary and homogeneous zero mean Gaussian stochastic process.System equations are linearized thus simplifying the numerical model of the device.Results of this approach have been compared with the ones obtained with a linear spring-damper controller, highlighting the capability to obtain a higher value of mean extracted power despite higher power peaks.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanics and Aerospace Engineering, Polytechnic University of Turin, Corso Duca degli Abruzzi 24, 10129 Turin, Italy.

ABSTRACT
The ISWEC (inertial sea wave energy converter) is presented, its control problems are stated, and an optimal control strategy is introduced. As the aim of the device is energy conversion, the mean absorbed power by ISWEC is calculated for a plane 2D irregular sea state. The response of the WEC (wave energy converter) is driven by the sea-surface elevation, which is modeled by a stationary and homogeneous zero mean Gaussian stochastic process. System equations are linearized thus simplifying the numerical model of the device. The resulting response is obtained as the output of the coupled mechanic-hydrodynamic model of the device. A stochastic suboptimal controller, derived from optimal control theory, is defined and applied to ISWEC. Results of this approach have been compared with the ones obtained with a linear spring-damper controller, highlighting the capability to obtain a higher value of mean extracted power despite higher power peaks.

No MeSH data available.