Optimisation of heterogeneous wave energy converter arrays: A control co-design strategy

Abstract

The commercial development and deployment of wave energy converters (WECs) will require arranging these devices in groups known as ‘arrays’, similar to the deployment other large-scale renewable energy systems, such as wind farms, or tidal arrays. This study explores a novel control co-design (CCD) strategy for heterogeneous arrays of point absorber-type WECs, focusing on the simultaneous optimisation of buoy hull geometry and array layout to harness multi-directional wind and swell wave energy. The WEC array operates under a newly developed global centralised control algorithm, which supports displacement constraints, but allows for the assessment of array performance in the frequency domain. This approach has the potential to significantly speed up the numerical solution of the control co-design optimisation problem, compared to more traditional time-domain-based methods. The array optimisation problem is solved using a global optimisation method. The performance function aims to optimise the positive network effect of interactions between devices in the array, while simultaneously considering cost issues, quantified by device sizes. The investigation identifies optimal device geometry and array layouts for clusters of three, four, and five WECs, in two different wave climates: Irish and Portuguese coasts, allowing the sensitivity of optimal solutions to different wave climates to be studied.