| With the gradual depletion of non-renewable energy, the exploitation of renewable energy has become a must for sustainable development in today's society and a key to the progress of science and technology for a nation in the future. Wind power resources are very rich in almost each country and region. Therefore many countries especially developed ones have made significant breakthroughs in the field of wind power generation. Single-machine capacity of WTG has been developed from tens of kilowatts to megawatts. The control technology of wind power generation and its frequency conversion technology as the key technique of wind power generation have become an important topic of new energy research.A multilevel matrix converter applied for the wind power generation system is studied in this paper, so as to obtain the good control performance of variable speed constant frequency and improvements of power quality. The combination of traditional wind power generation technology with the multilevel matrix converter (MMC) is consisted of a new high efficient wind power generation system based on the utilization of the advantages between matrix converter and multi-level inverter, which not only raises utilization rate of the wind energy, but also reduces the harmonic content of the output power and greatly improves the power quality delivered to the users by wind power generation system. The main research contents of the project include as follows.Firstly, the significance of the project, the current situation, the development trend of wind power generation technology, and the research of 3 kinds of typical matrix converters is described in this paper. Then the mathematical model and equivalent circuit of the permanent magnet synchronous generator are deduced,and the three most commonly used wind power tracking algorithms of VSCF wind power generation system are researched. Finally an improved climbing algorithm is put forward.Secondly, the topology of MMC is introduced. Space vector modulation of 2-level input line to line voltages and 3-level output line to line voltages is analyzed respectively in detail. Then the combined control strategy of input and output line to line voltages is analyzed. And the corresponding simulation models are set up. The corresponding simulated results are obtained, which have verified the feasibility of this dual line to line voltages space vector modulation strategy. Above all, a new topology of 3-1 MMC and a kind of 3-level space vector modulation strategy of virtual output line to line voltages has been put forward together with space vector modulation of 2-level input line to line voltages to obtain the combined control strategy. And the simulation verification has been given. The switching loss of MMC is analyzed in detail too laying a good basis for the further research.Finally, according to the structure of wind power generation system, the simulation model of wind power generation has been modeled based on multilevel matrix converter, which integrated MMC, wind turbine, permanent magnet synchronous generator and so on into a system and obtained the simulated experiment results under different wind speeds by means of corresponding control technologies.The experiment results have verified that the system can run stably and reliably under different wind speeds and improved the power quality greatly, thereby, have also verified the feasibility and advantages of the MMC used for wind power generation. The application future of this project is very good. It has laid the foundation for the application of multilevel matrix converter for the wind power generation system. |
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