Research On Speed Regulating System Of Permanent Magnet Synchronous Motor Based On Feedback Linearization Decoupling Sliding Mode Control

Permanent magnet synchronous motors are widely used in the fields of national defense, industry, medical, and civil applications due to the advantages of small size, simple structure, high power density, high efficiency and high reliability. This thesis takes permanent magnet synchronous motors as the object, studies different control strategies which can realize well dynamic and static performance of the control system. The main research contents are as follows:First, the mathematical model of PMSM is analyzed and established in dq coordinates by coordinate transformation theory. And based on this, combining id=0 vector control strategy with PI controller, double closed loop control system for PMSM is designed. Detailed description for the design of PI controller in each link is given and method of voltage feedforward decoupling is used to solve the problem of coupling phenomenon in the motor model. Theory analysis and simulation results show that vector control of PMSM has a well control effect.Second, based on the control method of exact linearization method in nonlinear system, the principle of feedback linearization is taken to implement input-output linearization of PMSM. This method divided the mathematical model of the system into two linear subsystems though the method of coordinate transformation and state feedback, which can realize both the linearization of the system and the exact decoupling for the coupling phenomenon in current and speed of the system. Then, the controllers for the two linear subsystems are designed by the principle of pole assignment. The simulation results show that the feedback linearization control has a better dynamic performance in aspect of motor control compared with traditional vector control.Third, combine the advantages of sliding mode variable structure control, this thesis proposes a new exponential reaching law control method with a terminal attractor to against the chattering problem in the system on the basis of traditional sliding mode reaching law control method. This method can effectively suppress the chattering phenomenon. Combining the modified sliding mode variable structure control method with the feedback linearization control, a better control effect could be achieved on the motor. The simulation results show that combining with the feedback linearization control and the modified sliding mode control not only can improve dynamic effect of the system, but also improve the robustness of the system.Finally, based on the existing facilities of laboratory, an experimental platform for PMSM control system is established. The traditional vector control of the PMSM control system experiments, feedback linearization control system experiments and sliding mode experiments are completed based on this platform. The experimental results verify that the control strategy has a good control performance in this thesis.