The Research On Detection Of Flux Parameters For Permanent Magnet Synchronous Motor

Permanent magnet synchronous motors had occupied apivotal position in industrial production area relying on its advantages such as high power density,smaller size and high efficiency.However,due to the complex operating environment of permanent magnet synchronous motor and the characteristics of the special structure of the permanent magnet synchronous motor itself,it is very easy to cause the demagnetization in the motor.In order to ensure the safe and stable operation of permanent magnet synchronous motor,it is very important to study the method to monitor the flux linkage of permanent magnet synchronous motor.Therefore,in this paper,the permanent magnet flux linkage of permanent magnet synchronous motor is monitored under the control strategy of id=0 and MTPA by establishing a proper mathematical model and using nonlinear control theory.The main contents of this paper are as follows:Under the control strategy of id=0,in order to improve control performance of permanent magnet synchronous motor,a sliding mode speed regulation method based on the on-line observation of permanent magnet flux linkage is adopted.Firstly,the sliding mode observer is used to construct the speed loop control model,and the effect of the load capacity caused by flux linkage of permanent magnet will be analyzed.Then,a new state equation for flux linkage parameters observation of permanent magnet synchronous motor is established under magnetic field oriented coordinate.Using the Luenberger observer keep the observer equation error free from motor speed.The stability of the sliding mode observer is proved by the Lyapunov stability theory.Based on the equivalent control principle of sliding mode variable structure,equation for permanent magnet flux linkage is constructed.Simulation results show the method is feasible.Under the control strategy of MTPA,a sliding mode observer based detection method for identification problems of permanent magnet flux linkage parameters is adopted for permanent magnet synchronous motor.By using the product of inductance and stator current under magnetic field oriented coordinate as state variables,a state equation for identification of permanent magnet flux linkage parameters is established for the permanent magnet synchronous motor.A method about combining the sliding mode variable structure control with state equation is used and a flux linkage sliding mode observer is designed.The stability of the sliding mode observer and convergence of the identified parameters is proven by Lyapunov stability theory.Simulation results show the feasibility of the method to the identification of permanent magnet flux linkage parameters for interior permanent magnet synchronous motor.Under the control strategy of MTPA,with regard to the problem that the traditional methods difficult to precisely detect the demagnetization of permanent magnet synchronous motor when the stator resistance parameter changes,a adaptive nonsingular terminal-sliding-mode control algorithm is discussed for permanent magnet synchronous motor.Firstly,the mathematical model of permanent magnet synchronous motor is established according to permanent magnet demagnetization condition.Then,adaptive observer and nonsingular terminal-sliding-mode observer is constructed for permanent magnet demagnetization detection and the adaptive estimation of stator resistance is given.The stability of the sliding mode observer is proved by the Lyapunov stability theory.Based on the equivalent control principle of sliding mode variable structure,equation for permanent magnet flux linkage is constructed.Finally,it is verified by simulation experiments that after changing the stator resistance parameter,the adaptive high-order sliding mode permanent flux observer can detect the flux parameters accurately.