Research On The Key Technologies Of Wave Energy Converter Of Inverse Pendulum

Energy is the material basis of human existence and production. The important problems such as the contradiction between Economic development and energy supply shortage, the causal relationship between traditional energy development and environmental degradation, International energy conflicts and energy security have attracted widespread attention all over the world. As a kind of ocean energy, wave energy is an abundant and renewable energy, which has drawn more and more attentions in many countries. The scientific large-scale exploitation of wave energy has important and far-reaching significance in the promotion of the sustainable development of national economy. The exploitation of wave energy has the unfavorable factors such as uncertainty, random fluctuations and the harsh marine environment, so the production of scientific,rational and economical wave energy converters not only affects the conversion efficiency and the cost directly, but also often determines the success of wave energy exploitation technology.There are several key technologies should be solved for the wave energy converter of inverse pendulum, which could be regarded as an integrated innovative system using wave energy to generate electricity. This paper attempts to demonstrate the feasibility of the dual-stroke acting hydraulic drive system, the substantially increase in the system efficiency, the viability and the reliability under the uncertainty wave conditions, the optimization of buoyancy swing wing structure, the realization of maximum energy capture and the stability of output power by means of theoretical analysis, simulations and experimental prototype plant tests.The main research content of the paper is summarized as follows:Based on the access to a large number of domestic and foreign literature, the first chapter discusses the background, purposes and the significance of the wave energy converters, then introduces the wave power generation technology and the achievements of the wave energy converter of inverse pendulum home and abroad. At last, the problems and the key technical issues needed to be solved immediately in the current research and the commercialization are presented.The second chapter analyses the fluid motion characteristics of wave fluid particles by means of the wave theory and the fluid dynamics theory, then the pitch movement theory of the buoyant swing in the zone of bottom waves is introduced. And the working principle and the structure components of the wave energy converter of inverse pendulum are also presented.The third chapter analyzes the key technologies of the wave energy converter of inverse pendulum. Firstly, a theoretical analysis of the hydrodynamic characteristics of the buoyant swing wing and the fluid-structure interaction multi-physics simulations using finite element method have been made., and then the design and calculation of the buoyant swing wing has been done based on the analysis of simulation results. Secondly, the dual-stroke acting hydraulic drive system is introduced briefly based on the comparison of the advantages and disadvantages of the various fluid power transmission system. Lastly, the electrical control system of the wave energy converter of inverse pendulum is designed.The fourth chapter focuses on the dual-stroke acting hydraulic drive system of the wave energy converter of inverse pendulum, including its design and working principle, the calculation and selection of hydraulic components and so on. And then the dual-stroke acting hydraulic drive system is modeled and co-simulated in the joint software AMESim and Matlab/Simulink, and the simulation results about the pressure-maintaining storage, constant frequency and the stability of output power have been analyzed and summarized.The fifth chapter firstly analyzes the operating conditions of the wave energy converter of inverse pendulum, and then studies the structure of the power system. Secondly, the maximum energy capture based on load control and the improved adaptive variable disturbulent step power observer control strategy is proposed. Lastly, the hardware and software of the controller system has been designed according to the operating functional requirements, and its structure and control algorithm has been modeled and obtains simulation verification.The sixth chapter introduces the 5kW prototype plant test and the semi-physical simulation test, the operating principle and the feasibility of the wave energy converter of inverse pendulum has been verified. And the conclusions including the whole performance has been summarized according to the analysis of the test results.The seventh chapter summarizes the whole paper's research work and the achievements, and also points out the the directions for further research.