Development of the next generation of controllers for wave energy devices

Project Description

This project is funded by a SFI Investigator Award and focusses on the development of nonlinear approaches to the modelling and control of wave energy devices. Oscillatory wave energy conversion (WEC) devices are required to operate in a wide range of sea states, presenting a variety of wave periods and amplitudes. WECs can be designed to resonate well at one particular frequency, but intelligent control systems must be employed to manipulate the power take-off (PTO) resistance so that the resonant frequency can effectively track the varying sea conditions. To date, linear WEC controllers have been employed to perform this adaptation. However, such controllers are based on linear hydrodynamic and PTO models, which obtain poor performance as oscillation amplitudes grow. In the wave energy case, the normal assumptions under which linearization is carried out (i.e. operation is maintained close to an equilibrium/linearization point) are violated, in part because of operation in high-energy seas and also because the objective of the controller is to exaggerate the motion of the device to resonance. This project aims to develop the next generation of wave energy controllers based on nonlinear hydrodynamic/PTO models which truly maximise wave energy capture. The maximisation of captured wave energy, through the application of intelligent control techniques, for a given device specification, is vital if wave energy is to become an economically viable form of renewable energy.