Research On The Power Control System Of Buoy-rope-drum Wave Energy Converters

Energy is the cornerstone of the development of human society.Nowadays,traditional energies represented by fossil energy are drying up and the environmental destruction caused by using traditional energies massively is becoming severe,so exploiting the clean and pollution-free renewable energy is urgently needed.Ocean wave energy is one kind of clean and abundantly reserved renewable energies which possesses outstanding prospect of development and utilization.However,there are many technical difficulties of wave power generation,which limits the industrialization of wave energy.One of the technical difficulties is that the energy conversion efficiency of wave energy converters(WEC)is low.This paper develops a power control system for the buoy-rope-drum wave energy converter which aims to control the operating state of the buoy-rope-drum WEC,making sure that the WEC running on the curve of optimal output power during the entire operating time.In this way,the energy conversion efficiency of buoy-rope-drum WEC will be improved significantly.First this paper proceeds mathematical analysis on the buoy-rope-drum WEC along with its subsystems and sets up the corresponding mathematical models,which provides the theoretical basis for the whole research.Then based on the mathematical models,the simulation platform of the buoy-rope-drum WEC is built in MATLAB/SIMULINK environment,providing an efficient analysis method for the subsequent research works.In order to improve the energy conversion efficiency of the buoy-rope-drum WEC,a logical control strategy is needed to make sure that the buoy-rope-drum WEC outputs maximum power during the entire operating time.Chapter three studies on the methods of realizing maximum power output and the maximum power point tracking(MPPT)algorithms,presenting a novel perturbation and observation(P&O)MPPT algorithm which has a power classification standard and a variable step size standard compared with the traditional P&O MPPT algorithms.Utilizing the simulation platform of the buoy-rope-drum WEC,computer simulation experiments of the power control system under simulated marine environment and simulated laboratory environment are proceeded respectively.The results preliminarily prove the effectiveness of the power control system.In chapter five,the overall architecture of the power control system is confirmed,then the hardware structure and the system software are developed.When the development of the prototype of the power control system is finished,an output power control experiment is proceeded in laboratory.The results verify the effectiveness of the power control system further.According to the results of computer simulation experiments and the laboratory prototype experiment of the power control system,it can be proved that the power control system controls the buoy-rope-drum WEC outputs maximum power effectively during the entire operating time,realizing the goal of maximum power point tracking and improving the energy conversion efficiency of the WEC.