Optimization study on a square array of wave energy converters in irregular waves

Abstract

In this study, a wave energy converter (WEC) array is optimized in multi-frequency incident wave conditions. The findings are compared with the results obtained from arrays in single-frequency incident wave conditions, with the aim of determining an array parameter configuration method suitable for irregular waves. Taking a square array composed of four identical cylindrical heaving WECs as an example, four variable parameters are considered, namely the buoy radius and draft, damping of the power take-off (PTO) system, and the spacing between WECs. The differential evolution (DE) algorithm is adopted for multi-parameter optimization. Based on linear potential flow theory, the high-order boundary element method is selected to solve the hydrodynamic interaction between waves and WECs. The results indicate that the array layout obtained in multi-frequency incident waves exhibits good power performance over a wide frequency range, as well as in unidirectional and multi-directional irregular waves, but with high-cost indicators and elevated computational costs. The array obtained by optimizing the spacing between adjacent pre-designed WECs, with large PTO damping and small suboptimal buoy submerged volume, can balance the high power and low cost indicator of the array in irregular waves.