The Research On Control Strategies In Permanent-magnet Direct-driven Wind Power Conversion System

It is very important to develop and utilize wind power which is non-polluted and very rich on the earth as conventional energy in shortage and environment pollution problem more serious .Wind power generation technique is improved greatly, thanks to that more and more countries all over the world pay more attention to it, coming out many types of wind power generators. Permanent-magnet Direct-driven wind power system is paid more and more attention as an important direction of wind power generation in the future because of its own advantages such as non-gear, lower cost, less noise.With the operation and control of Permanent-magnet Direct-driven wind power converter as the research subject, this thesis made complete study by simulation and experiment, introduced and compared two control strategies of Permanent-magnet Direct-driven wind power system, focused on Doubly-PWM wind power system.First, this thesis introduced the development situation about Direct-driven wind power system around the world, and discussed control strategies of some kinds of wind power systems. Then, the operation principle of the wind power system was introduced, the structure and the mathematic model of the Boost Converter wind power system was analyzed as well as the control strategy was introduced. Doubly-PWM Permanent-magnet Direct-driven wind power system was studied deeply in this thesis, mathematic models of all parts of the system were established and analyzed. Rotor field orientation control strategy in generator-side and voltage orientation control strategy in grid-side were proposed according to the mathematic model of the system. Simulation and comparison of the two systems that proposed in this paper were made by using Matlab/Simulink, demonstrating that Doubly-PWM has more better effect and has less harmonic. Control platform was established to imitate the real system in laboratory, a dynamic simulation was implemented to check the proposed algorithm, and the results of the experiments verified the good performance of the control strategy.