Constrained control of arrays of wave energy devices

Abstract

a b s t r a c tIt is well known in the literature that the total absorbed energy of a farm of wave energy converter depends, within a wide range of variability, on the hydrodynamic interaction between the individual devices. Several studies have addressed the problem of controlling the wave energy converters so as to exploit the positive interaction between the devices in order to increase the total amount of absorbed energy.This paper studies two types of control systems for array of wave energy converters: the first is similar to the classical optimal control which uses the complete (linear) hydrodynamic model of the array and information about the status (velocity) of the other devices, while the second is a suboptimal control systems which calculates the optimal motion while neglecting completely the interaction between the devices. Most importantly the comparison is carried out considering the effects of constraints on the maximum allowed oscillation amplitude and PTO force.

Receding horizon pseudospectral optimal control for wave energy conversion

“…Various methodologies were developed in order to answer optimal control problem, among which MPC and pseudospectral control. The algorithm presented here is based on the pseudospectral optimal control to generate the reference trajectory to be followed by the WEC [7].…”

“…Model Predictive Control (MPC), introduced in the wave energy domain [1], allows an energy maximisation while ensuring the respect of path constraints, leading to an interesting and realistic approach for the control of WEC. More recently, pseudospactral optimal control was introduced in an energy maximisation problem for wave energy conversion [7], and recently improved in [8] allowing its application in real-time via a receding control horizon. The present study introduces the receding horizon pseudospectral control and compare its performance with a standard MPC algorithm.…”

“…Development of Wave energy converters constitutes an actual topic of research, in their designs and fluid-interactions, and particularly on their controllability. Immersed WECs are subject to fluid-interaction forces, generating unusual solicitations specific to hydrodynamic equation, such as radiation force or excitation forces.Various control strategies were recently developed and more advance control algorithms are currently applied on WECS, such as Model Predictive Control [1], or Pseudospectral optimal control [2]. Such control strategies, capable of maximizing the energy production while insuring the respect of path constraints, are more realistic and applicable in real conditions involving technological limitation aspects.…”

“…Various control strategies were recently developed and more advance control algorithms are currently applied on WECS, such as Model Predictive Control [1], or Pseudospectral optimal control [2]. Such control strategies, capable of maximizing the energy production while insuring the respect of path constraints, are more realistic and applicable in real conditions involving technological limitation aspects.…”

Nonlinear Passive Control of a Wave Energy Converter Subject to Constraints in Irregular Waves

“…Furthermore, the time domain study is needed if the constraints are considered. In recent studies [28,29], Bacelli et al studied the maximization of energy production of WECs under displacement constraint based on the approximation of the motion of the WEC and of the PTO force by means of a combination of basis functions.…”