Maximum Power Point Tracking Control Of Direct-Drive Ocean Wave Power Generation System

With the high-speed development of modern technology,the globalization of the natural gas market and the turmoil in petroleum yield,the current world energy pattern is in the profound change.Actively developing clean,efficient,green and low-carbon new energy sources has become the focus of energy research in countries around the world.As a kind of renewable energy which is large in distribution and reserve and clean without pollution,ocean wave energy has an enormous potential in development.It is significant for the acceleration of energy structure transformation,the alleviation of energy crises and the improvement of ecological environment.The content of this paper focuses on direct-drive ocean wave power generation system and maximum power point tracking(MPPT)control.Main work as follows(1)The theory analysis and modeling of direct drive wave power generation system:analyzing the properties of wave excitation force and the floater of the power generation system,and establishing the mechanics model of power generation system and dynamic model of the permanent magnet synchronous linear generator.(2)Studying a single-degree-of-freedom maximum power tracking control method for a direct-drive ocean wave power generation system.Three-phase rectifier bridge and Boost chopper circuit is used as the AC-DC conversion circuit of the machine-side controller.And proposing a tracking control method of the maximum power in single-degree-of-freedom based on fuzzy logic control which aims at the problems of slow response speed and power fluctuation in traditional perturbation and observation method in the application of ocean wave power generation system.The method combines fuzzy logic control with perturbation and observation method and controls the boost circuit duty cycle to adjust the generator's electromagnetic force amplitude to achieve maximum power tracking control.By Simulink simulation,it is verified that the proposed algorithm has better fast response and robustness while retaining the advantages of perturbation and observation method.(3)Studying a double-degree-of-freedom maximum power tracking control method for a direct-drive ocean wave power generation system.Three-phase full-control rectifier bridge circuit is used as the AC-DC conversion circuit of the machine-side controller.And proposing a tracking control method of the maximum power in double-degree-of-freedom based on genetic algorithm which aims at the problem of low energy capture efficiency of direct-drive ocean wave power generation system under irregular waves.The method first identifies the optimal parameter conforming to the power generation system in present sea state based on genetic algorithm,then achieve the maximum power tracking control under the excitation of regular and irregular ocean wave using space vector control algorithm to adjust amplitude and phase position of electromagnetic force of the generator.Simulink simulation indicates that the proposed algorithm can effectively improve the energy capture efficiency of power generation system.(4)Establishing simulative experiment platform of direct-drive ocean power generation system.Based on the existing experimental conditions,designing hardware circuit of the machine-side controller based on the single-degree-of-freedom control method,programming the maximum power tracking control algorithm.And making a experiment test in simulative experiment platform and proving feasibility and validity of the controller and MPPT algorithm in the actual application of power generation system.