The Research On Flux Estimation In Direct Torque Control System Of Permanent Magnet Synchronous

Direct torque control(DTC)has the advantages of simple control structure,fast dynamic response and small dependence on parameters.The observation of stator flux is a very important link in direct torque control.The accuracy of stator flux observation directly affects the performance of the control system.When the stator resistance changes,it will affect the accuracy of the stator flux observation.At the same time,in order to ensure the accuracy of stator flux linkage observation of permanent magnet synchronous motor,besides stator resistance,there are other parameters of motor,such as stator inductance and rotor flux.According to the parameters of permanent magnet synchronous motor changes such as stator resistance,stator inductance and rotor flux caused by the accuracy of the stator flux observer is analyzed and improved,this paper combines the iterative algorithm for inequality identification of stator resistance and stator inductance and rotor flux with finite memory least squares method,proposes a new stator flux observer model reference adaptive control based on.In this paper,the mathematical model of permanent magnet synchronous motor is established.According to the basic principle of direct torque control,the influence of stator flux linkage observation caused by stator resistance,stator inductance and rotor flux linkage is analyzed.First,in order to reduce the influence of other motor parameters on the stator flux observation accuracy,the stator resistance,stator inductance and rotor flux linkage of the permanent magnet synchronous motor are identified,but the stator resistance identification is not accurate enough.In this paper,the finite memory least squares method is combined with the model reference adaptive method.The parameter identification of the stator inductance and the rotor flux can solve the problem of low real-time performance and data saturation of the traditional least squares method.It can not only enhance the parameteridentification Accuracy and rapidity also ensure the accuracy of stator flux observations.Secondly,in this paper,aiming at the disadvantage that the least square method does not accurately identify the stator resistance,an iterative algorithm of linear matrix inequality is used instead of the pole configuration method to obtain the gain matrix of the observer.The adaptive law of the stator resistance is designed according to Lyapunov stability theory.To overcome the problem of inaccurate observation accuracy of the pole assignment method and uncertainty of the proportional coefficient,the accuracy of the stator flux observation is enhanced,and the method is verified by simulation.In order to reduce the influence of other motor parameters on the stator flux observation accuracy,other parameters of the permanent magnet synchronous motor such as stator inductance and rotor flux linkage were identified.The simulation platform of the permanent magnet synchronous motor direct torque control system is set up in this paper,and a new adaptive flux observer simulation model is designed.At the same time using Matlab/Simulink and code compiler(CCS)built a software in the loop(SIL)simulation system,and the system of single-phase pulse width modulation(PWM)inverter circuit model and TMS320F28335 type digital signal processor(DSP)based on the control system of the software in the loop and hardware in the loop simulation experiment.