scholarly journals Time-varying linear quadratic Gaussian optimal control for three-degree-of-freedom wave energy converters

2020 ◽  
Vol 149 ◽  
pp. 217-225 ◽  
Author(s):  
Shangyan Zou ◽  
Ossama Abdelkhalik
Keyword(s):  
Optimal Control ◽  
Wave Energy ◽  
Degree Of Freedom ◽  
Time Varying ◽  
Linear Quadratic ◽  
Linear Quadratic Gaussian ◽  
Wave Energy Converters ◽  
Three Degree Of Freedom ◽  
Energy Converters

On the Control of Three-Degree-of-Freedom Wave Energy Converters

2017 ◽  
Author(s):  
Shangyan Zou ◽  
Ossama Abdelkhalik
Keyword(s):  
Wave Energy ◽  
Degree Of Freedom ◽  
Linear Quadratic ◽  
Linear Quadratic Optimal Control ◽  
Wave Energy Converters ◽  
Control Comparison ◽  
Quadratic Optimal Control ◽  
Pseudo Spectral Method ◽  
Three Degree Of Freedom ◽  
Pseudo Spectral

The control of a three-degree-of-freedom (3-DOF) wave energy converter (WEC) is considered in this paper. Recently, several methods have been developed in the literature for this problem. This paper is a comparison between three methods: the non-linear model predictive control, the pseudo-spectral method, and the time-variant linear quadratic optimal control. Comparison between the three methods is presented in terms of the harvested energy.

scholarly journals Revisiting Theoretical Limits for One-Degree-of-Freedom Wave Energy Converters

2020 ◽  
pp. 1-11
Author(s):  
Nathan Tom
Keyword(s):  
Power Generation ◽  
Wave Energy ◽  
Degree Of Freedom ◽  
Upper And Lower Bounds ◽  
Complex Conjugate ◽  
Hydrodynamic Coefficients ◽  
Damping Coefficients ◽  
Wave Energy Converters ◽  
Heave Motion ◽  
Energy Converters

Abstract This work revisits the theoretical limits of one-degree-of-freedom wave energy converters (WECs). This paper considers the floating sphere used in the OES Task 10 WEC modeling and verification effort for analysis. Analytical equations are derived to determine bounds on displacement amplitude, time-averaged power (TAP), and power-take-off (PTO) force. A unique result found shows that the TAP absorbed by a WEC can be defined solely by the inertial properties and radiation hydrodynamic coefficients. In addition, a unique expression for the PTO force was derived that provides upper and lower bounds when resistive control is used to maximize power generation. For complex conjugate control, this same expression only provides a lower bound, as there is theoretically no upper bound. These bounds assist in comparing the performance of the floating sphere if it were to extract energy using surge or heave motion. The analysis shows because of differences in hydrodynamic coefficients for each oscillating mode, there are different frequency ranges that provide better power capture efficiency. The influence of a motion constraint on TAP while utilizing a nonideal power take-off is examined and found to reduce the losses associated with bidirectional energy flow. The expression to calculate TAP with a nonideal PTO is modified by the mechanical-to-electrical efficiency and the ratio of the PTO spring and damping coefficients. The PTO spring and damping coefficients were separated in the expression, allowing for limits to be set on the PTO coefficients to ensure net power generation.

scholarly journals Adaptive Optimal Control of Wave Energy Converters

2018 ◽  
Vol 51 (29) ◽  
pp. 38-43 ◽  
Author(s):  
Siyuan Zhan ◽  
Bin Wang ◽  
Jing Na ◽  
Guang Li
Keyword(s):  
Optimal Control ◽  
Wave Energy ◽  
Adaptive Optimal Control ◽  
Wave Energy Converters ◽  
Energy Converters

Active control for multi-degree-of-freedom wave energy converters with load limiting

2020 ◽  
Vol 159 ◽  
pp. 1177-1187 ◽  
Author(s):  
A.J. Hillis ◽  
C. Whitlam ◽  
A. Brask ◽  
J. Chapman ◽  
A.R. Plummer
Keyword(s):  
Active Control ◽  
Wave Energy ◽  
Degree Of Freedom ◽  
Wave Energy Converters ◽  
Energy Converters
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