Research On Power Capture Characteristics And Power Prediction Of Wave Energy Converters Used On Mooring Floating Platform

Developing marine instruments,expanding marine equipment industry and promoting the development and utilization of marine energy are important ways to build a marine power country.Due to harsh conditions of ocean,traditional power supply means cannot provide continuous and stable electric energy for marine instruments.The problem of power supply is restricting the wide promotion of marine instruments and equipment.The vast sea area in China is rich in marine energy.As a new type of renewable energy,it has the characteristics of centralized energy distribution and high theoretical energy capture efficiency.Promoting the development and application of marine energy on marine instruments is the main way to solve the power supply problem of instruments.This dissertation studies hydrodynamic characteristics of floating bodies on the wave energy power generation device of anchored floating platform with different shapes.Calculate the capture power of the frustum of a cone shaped floating body,analyze the key factors affecting power generation,establish a prediction model to predict the output power,and introduce relevant parameters to evaluate the accuracy of the model finally.This dissertation firstly describes the research background and significances of this subject,and introduces several typical wave energy converters and their applications.It also discusses the strategies to improve power generation,and reviews wave energy generation technology and application of machine learning in this field at home and abroad.Finally,it illustrates research contents of this dissertation.After that,it introduces wave theory used in this paper,including linear wave theory,Stokes wave theory,and irregular wave theory.After giving governing equations and boundary conditions,velocity potential function,wave surface function,dispersion relationship,velocity and acceleration of water points are calculated.Then,wave surface equation of irregular wave at fixed and non-fixed points,and frequency spectrum and directional spectrum used to describe energy distribution are introduced.It studies hydrodynamic characteristics of floating bodies with different shapes,which are cylinder,cone,hemisphere,and the frustum of a cone shaped floating.A mathematical model with linear power output system is established.The response characteristics of floating body in the time domain under P-M spectrum excitation,as well as in the frequency domain,are studied by numerical simulation.The hydrodynamic differences between four floating bodies are compared and analyzed.Half apex angle’s effects on hydrodynamic and motion characteristics of the frustum of a cone shaped floating body are investigated further.The power calculation formula of the frustum of a cone shaped floating body are deduced,and key parameters that effect the capture power are determined.A sample database is established using the Latin hypercube sampling method.Wave excitation force,additional mass,radiation damping,and capture power of samples are calculated.Finally,a correlation analysis is conducted to quantify parameters’ correlation with capture power.The maximum energy capture power of the dome shaped floating body are predicted.It designs a three-layer feedforward neural network.After dividing the training and verification set,it is used to calculate sample’s maximum capture power under different wave conditions.Introduce the correlation coefficient,root mean square error,error percentage,and P value to analyze the consistency between forecasting results and simulation results and evaluate model’s accuracy.Finally,it summarizes the full text.It lists main conclusions and innovations,and makes research prospects.