| The energy crisis,the deterioration of the ecological environment and the warming of the climate are becoming increasingly serious problems worldwide,and there is a general consensus among countries and regions on the development of renewable energy sources,which are abundant in the oceans and seas,which cover 71 per cent of the Earth’s surface area,and are an important way to address them.In recent years,the research and development of wave energy conversion devices has been rapid,and the technology of oscillating float type wave energy generation devices is relatively mature,but in the process of industrialization and application,it also faces problems such as improving efficiency and reducing manufacturing costs.In this paper,we study the influence laws of various design parameters on the energy capture power and efficiency of floats based on the oscillating float type wave energy power plant,and establish the power output surrogate model,combined with the float manufacturing cost function,the multi-objective optimization objective function,and give the design reference for different power levels under the typical offshore conditions in China.This thesis begins by describing the background and significance of the research,introducing the main classifications of wave power generation devices,summarizing the main ways to increase the energy capture power at home and abroad,comparing the research status,describing the working principle of oscillating float type wave power generation devices,combining the research status and proposing the research content of this thesis.Secondly,the theoretical basis of potential flow theory is introduced.By giving the control equation and boundary conditions,the results of the velocity potential and hydrodynamic coefficients under regular wave excitation are obtained,and the kinetic and kinematic model of the float’s sagging motion is built on this basis,and the capture power frequency domain model is obtained.Six models of typical sea conditions in China’s offshore waters based on the P-M spectrum.Then,the working principle of AQWA,a hydrodynamic solver based on the boundary element method,is introduced,and the validity of the calculation results is verified.The influence of AQWA on the float energy capture power frequency domain results and the energy capture power under irregular wave excitation is studied from the perspective of float geometry,external dimensions and PTO dampingAgain,several mainstream surrogate model building methods and the sample library building method using Latin hyper cubic design are introduced,the working principle of artificial neural network surrogate model building is described,the surrogate model with WEC design parameter as input capture power as output is built by ANN based on L-M algorithm,and the accuracy of the surrogate model is evaluated.Finally,the principle of NSGA algorithm is introduced,and a multi-objective optimization model is built with the float resonance frequency constraint as an objective function of maximizing capture power,minimizing float displacement and surface area,and obtaining optimization results under typical offshore conditions in China. |
