Research On Speed Sensorless Control System Of Permanent Magnet Synchronous Motor Based On Parameter Identification

Permanent magnet synchronous motor(PMSM)has the advantages of relatively simple system structure,easy to control,large speed adjustable range and high Starting performance,etc.Therefore,it has been applied in the field of high performance motor drive such as robot,computer numerical control device,high-speed railway drive system.When the PMSM is running under different load conditions,when the ambient temperature,the saturation of the motor circuit changes or the cross-coupling of the motor circuit occurs the main electromagnetic parameters may also change,It is more difficult to modeling and synchronous analyze.and it is difficult to carry out linear analysis with traditional methods.Aiming at this problem,this thesis makes an intensive study on the identification of PMSM parameters of q-axis and d-axis,the design of vector control strategy and its improvement and optimization based on the finite element model of PMSM.The main research contents are as follows:Firstly,several mathematical models in different coordinate systems,PMSM control strategy,PI control and SVPWM technology of PMSM are studied,and the simulation of PMSM control system in MATLAB/Simulink,which provide a basis for control system optimization,parameter identification algorithm design and field circuit coupling analysis.Secondly,the on-line identification of motor parameters based on model reference adaptive(MRAS)method is studied,and the on-line identification of main electromagnetic parameters of PMSM is studied;And the motor speed and rotor position estimation based on this method to realize the speed sensorless control of the motor.Then,using FEA of the PMSM,the running state of the PMSM under different saturation degrees of magnetic circuit is analyzed,and the variation laws of main electromagnetic parameters when considering the cross coupling effect of magnetic circuit.Through three-dimensional interpolation and Fourier decomposition,The fitting curves and general fitting polynomials of the main electromagnetic parameters of the motor under different magnetic circuit saturation degrees are obtained.Finally,according to the variation law of the main electromagnetic parameters of the above motor,the regulator of the PMSM vector control system is improved and optimized,and the fitting polynomial is applied to the PI parameter setting link in the motor control strategy.Through the field circuit coupling simulation,the variable PI parameter control analysis of the PMSM is realized,the adaptive control of the motor is realized,and the control performance is improved.In addition,through the comparative analysis of the control effects of different operating states of the motor,the correctness of the calculation method of the main electromagnetic parameters of the motor and the effectiveness of the motor control strategy proposed in this thesis are verified.