71 / 2021-03-29 19:43:20

Shape Optimisation of a Point Absorber Wave Energy Converter in Random Waves

Wave Energy Converter; Optimization algorithms; Shape optimization; Control strategy

This paper presents a systematic methodology to optimise the geometry of a point absorber wave energy converter, to maximise its energy extraction in given sea states and in site-specific wave climates. A two-layer optimization routine is proposed to find the optimal design and control variables. The inner-layer optimization is to find optimal control parameters the power take-off system. The out-layer optimization, which uses a genetic algorithm and a surrogate-based optimization algorithm separately, is employed to find optimal design parameters of the device’s geometry that is mathematically defined by a spline function. In the case study, the proposed methodology is applied to a direct-drive point-absorber type wave energy converter. Numerical results indicate that the system efficiency is significantly improved, and a high capture width ratio of 77% is found for random waves.