On Fuzzy Control Method Of Speed For Permanent Magnet Synchronous Motor

Permanent Magnet Synchronrous Motor (PMSM) is a highly nonlinear and coupling, structure varying, and multivariable object. Permanent Magnet Synchronous Motors are widely used in industrial and agricultural production and the field of Aeronautics and Astronautics for their advantages, such as compactness, high efficiency, reliability and adaptability to the environment. With the continuous development of these areas, the speed control system for PMSM is urgently needed to have better precision, wider speed-regulating range and faster response. Based on the basic theory of fuzzy control, a fuzzy PI controller and a robust H∞controller of T-S fuzzy system are designed, respectively. The main contributions are listed as follows:Firstly, in this thesis the mathematical model of PMSM is built under the dg0coordinate. After analysis of vector control strategies, it chooses id=0control strategy to decouple the system. To deal with the variation of the parameters in PMSM, this thesis adopts the fuzzy strategies, and deduces the fuzzy principle, and designs the fuzzy PI controller based on the operating characteristics of PMSM, and then gives the effect diagram of the controller.Secondly, the robust H∞controller of T-S fuzzy system for PMSM is studied. It has already been proved that the T-S fuzzy model can approximate any large-scale nonlinear systems under the certain conditions. In this thesis, the mathematical model of PMSM is built by using the method of T-S fuzzy model based on the operating characteristics of PMSM. Based on Lyapunov stability theory and robust control theory, a new stability theory is given and proved, which has a low cost. And then, the robust H∞controller for PMSM is designed which is based on the new stability theory.Then, PMSM is simulated by using the PI controller, fuzzy PI controller, and robust H∞controller of T-S fuzzy system, respectively. The simulation results of the PMSM prove the designed controllers’ feasibility and effectiveness. At the end, this thesis summarizes the whole work we have done, and then gives some conclusions and points out some future work.