Ermakov, A., Marie, A. & Ringwood, J. (2022) – Optimal control of pitch and rotational velocity for a cyclorotor wave energy device

The LiftWEC project has published a new peer-reviewed research article!

The paper entitled “Optimal control of pitch and rotational velocity for a cyclorotor wave energy converter” was published in IEEE Transactions on Sustainable Energy by Dr Andrei Ermakov, Dr Alice Marie, & Professor John Ringwood. The final paper is available for download at IEEE Transactions on Sustainable Energy.

Abstract: The development of optimal control strategies for cyclorotor wave energy converters (WECs) is at an early stage. In this paper, we present new methods and solutions for optimal pitch and/or rotational velocity control strategies for different configurations of cyclorotor-based WECs, in both monochromatic and panchromatic waves. The cyclorotor is modelled with the use of an approximate two-dimensional mathematical model, where hydrofoils are approximated as point source vortices in potential waves. The goal of the developed control strategy is to determine the optimal velocity profile, and/or pitch angle variations, for maximum energy conversion, in terms of generated shaft power. The solutions, obtained with the use of spectral methods, show a clear benefit in using a variable velocity for cyclorotors with either one or two hydrofoils, in monochromatic waves, while the real time pitching did not significantly increase the value of the absorbed wave energy. We also present control results for panchromatic waves, assuming all the properties of incoming wave packages are known. The obtained solutions have shown significant benefit in joint optimal pitch and velocity control, especially in the case of panchromatic waves.

Keywords: Wave Energy Converter, Cyclorotor, Optimal Control, LiftWEC, Lift-Based Wave Energy Converter