Research On Vector Control Of PMSM Based On Sliding Mode Variable Structure Control

In recent years,with the continuous progress of science and technology,new type of power electronic devices and high performance materials are developed and used.The emergence of new permanent magnet material makes PMSM developed more and more fast in various areas.The control strategy of PMSM becomes a hot topic for experts and scholars to be discussed.The vector control based on magnetic field orientation is an excellent control strategy with precise control performance.It becomes one of the most important control strategies in the field of PMSM control because of its simple control and easy realization.The research content of this thesis is vector control of PMSM.Improving the motor's dynamic response speed and reducing steady-state error are the important performance indicators that are continuously pursued by modern motor control.VSC(Variable Structure Control)theory is an advanced nonlinear control theory proposed by the former Soviet scholar in the 1950 s.The control is characterized by the fact that the control mode is not static and the control state changes according to the system state.There are several different control modes in the controller,those modes are constantly switching in a high frequency to achieve the intended control purposes.SMC(Sliding Mode Control)is a new control theory developed by the VSC.The most prominent advantage of sliding mode variable structure control is that the design of the control model is not dependent on the control object's model.The control isn't sensitive to the perturbation of the system parameters and has strong robustness,so it is widely used in the field of motor control.In this thesis,the PMSM vector control is taken as the research object,and the SMC is introduced into the traditional vector control.In order to reduce the steady-state error of the speed regulation,the integral SMC is designed into the controller.The PMSM's control needs to know its precise rotor position and speed information,the use of sensor to detect PMSM's speed and position makes the motor's structure complex and reduces the reliability of the control.This thesis designs two kinds of control strategies to detect the PMSM rotor's information,one is model reference adaptive observer control strategy based on the SMC,the other is the sliding mode observer control strategy.Finally,the simulation models were built to verify the control performance,the simulation results show that the designed control strategies can effectively detect the rotor phase and speed of the PMSM,and realize the PMSM speed sensorless control.