Research On The Tubular Permanent Magnet Linear Generator Using Direct-Driven Wave Power Take-Off System

Wave energy is a kind of inexhaustible and renewable resource. It storages huge amount of storage in the ocean, and energy density is much greater than solar and wind energy. The development and utilization of wave energy has great realistic significance for solving environment pollution and energy crisis. The structure of direct drive due to the lack of the middle conversion device such as hydraulic device and gears, it has becoming a hot topic discussed by experts and scholars with the simple structure, high energy conversion efficiency, easy maintenance and so on. The whole cake type winding of cylinder permanent magnet linear generator is effective, and it has no end-winding, so the utilization rate of the winding is improved. The permanent magnet linear generator and buoy connect together by bolt and fit for integration and installation.Firstly, according to the structure of linear generator, the structure of short primary and long secondary suits in the wave power generation. Then, based on the finite element and Fourier decomposition, optimized the structure of generator, a convex primary structure is present to reduce the end force. According to the design of electromagnetic parameters, two generators which used for wave power system are manufactured; one is small power that verifies the electromagnetic parameters of the generator and discusses the feasibility of wave power generator. Base on laboratory research, a generator which power reaches 1 KW is designed, and manufacture a floating type direct-drive wave power system. The result of the sea test showed that the permanent magnet linear generator can effectively convert wave energy to electricity.The fruits of this thesis are as follow:? From the wave theory, the sea wave motion equation is deduced and calculated the wave energy. Using the capture width, it provides theoretical supports for designing the size of the float. According to Newton's second law, establish the motion equation of direct-drive wave power system and has a guiding significance for the system.? The two-dimensional simulation model is set up using Finite Element Analysis. Magnetic field distribution of the generator and electromagnetic parameters is calculated.? Using numerical analysis method, the magnetization of axial, radial, quasi-halbach and the structure of halbach which composed 8 piece permanent magnet are analyzed. Conclusion shows that the air-gap density for the structure of 8 halbach in both the sine degree and numerical was superior to other forms of structure.? Combined with Fourier decomposition and finite element analysis, deduced the relationship between detent force and the number of slots and poles. The results shows that the detent force of 9 poles 10 slots is smaller than 8 poles 12 slots for the same primary. Using bulged ststors and auxiliary slots can great reduced detent force. Electromagnetic properties are improved by optimizing the structure of generator.? Using the numerical analysis and finite element analysis, the air-gap flux density is analyzed for axial, radial and quasi-halbach magnetization. Studied shows that the air-gap flux density is higher for halbach than other magnetization, and the sinusoidal performance is better than other structures.? According to finite element analysis, an external tubular linear permanent magnet generator (ETLPMG) is proposed for direct drive wave energy conversion to improved power density. The calculation results show that the power density of ETLPMG is about 6-8 times than the internal one for the same size.? A small power generator is designed and manufactured by calculation and optimization under the laboratory environment. No-load and load experiment is tested for wave tank and results shows the direct-drive system can efficient convert the wave energy to electricity. The relevant parameters of generator are verified, and accumulate the experience for sea experiment.? Design and manufacture a floating direct-drive system using ocean environment. A series experiment is tested in Lianyungang sea area. Results shows that this kind of system can convert wave energy to electricity effectively which has an important guiding role for the further research for large scale.