Nonlinear Control Of Permanent Magnet Synchronous Wind Power Generation System Based On Inverse System Method

In order to tackle the more and more serious fossil fuel energy shortage and environmental pollution problems, various countries in the world focus on the development of renewable clean energy, in which wind energy is one of the most promising new clear energy. The effective control of wind power generation system can guarantee the high efficiency, high performance of the system. But wind power generation system is high nonlinear and stochastic. In this thesis, the inverse system method and linear quadratic Gaussian(LQG) optimal control theory is used to investigate the nonlinear control of permanent magnet synchronous wind power generation system. The main contributions of the thesis can be summarized as follows:(1) The construction of the permanent magnet synchronous wind power generation system is briefly introduced. The dynamic model of the wind turbines, generators, transmission systems, detection and control systems is established.(2) For the wind power generation system operating under rated wind speed, the inverse system is constructed for the nonlinear dynamic model of the system. Then, a exact linearization feedback controller is constructed. Based on the linearized dynamic model, a LQG optimal controller is put forward. The stability of the closed loop system is analyzed as well. Finally, the simulation model of the permanent magnet synchronous wind power generation system is constructed based on the MATLAB/ Simulation platform. The simulation results demonstrate the effectiveness of the proposed maximum wind energy capture control scheme.(3) When the wind speed is higher than the rated speed, a variable pitch controller is proposed by the usage of inverse system method. The proposed controller is designed based on the original nonlinear dynamic model of the system and can overcome the shortages of the conventional approximation linearization method. Therefore, the response to the change of wind speed is more sensitive and pitch motion can track the change of wind speed quickly. Simulation results show that the proposed variable pitch control strategy can achieve the constant power control of permanent magnet synchronous wind power system effectively.