Research On Sensorless Control System Of Permanent Magnet Synchronous Motor

Permanent magnet synchronous motor have many advantages,such as simple structure,high efficiency,and high power density.It have been widely used in many fields such as industry,aerospace,transportation and household appliances.In the vector control system of permanent magnet synchronous motor,the motor speed and rotor position usually need to be obtained by mechanical sensors,which causes the motor to be limited by the application and operating environment,and the position sensorless control technology can broaden the application range of the motor and improve the reliability of the system.Therefore,it is of theoretical and practical value to study the position sensorless control technology with high control precision,strong robustness and wide speed range.In order to design the vector control system of permanent magnet synchronous motor,the mathematical model in different coordinate systems is builted.At the same time,the basic principle of vector control and the commonly used control methods are analyzed and compared.Through the analysis,the vector control method id=0 with the advantages of simple and flexible implementation process and good torque characteristics is selected,and the parameter design of PI regulator and space vector pulse width modulation technology in vector control system are discussed in detail.On the basis of the vector control system of permanent magnet synchronous motor,the estimation accuracy of the model reference adaptive observer is reduced for the motor parameter variation disturbance,and the single parameter PI controller as the adaptive law makes it difficult for the system to achieve the performance in the wide speed range.The problem is based on the sliding model reference adaptive position sensorless control strategy,which combines the model reference adaptive algorithm with the sliding variable structure control method,and uses the reference model of the motor body and the output difference structure of the corresponding adjustable model.The sliding surface switching function replaces the PI regulator as an adaptive law by the sliding surface switching function,which enhances the robustness of the system parameter perturbation and the adaptability to interference.For the chattering phenomenon of sliding variable structure control,it is suppressed from two aspects:on the one hand,Sigmoid function is used to replace the traditional mode switching function,on the other hand,adaptive adjustment of the sliding model gain value by fuzzy control.In order to verify the effectiveness of the adopted strategy,a simulation model was built on the Matlab/Simulink platform,and the simulation comparison analysis was carried out under the conditions of sudden rotation speed,load mutation and motor parameter variation.The simulation results show that the improved method has high observation accuracy,strong robustness and wide application speed range.A two-level inverter hardware platform based on TMS320F28335 is builted.The software program is designed and written in the CCS7.4 software environment,then the speed regulation experiment is carried out.The experimental results show that the observed motor speed and rotor position are consistent with the actual values.,which verifies the feasibility and effectiveness of the proposed strategy.