Sensorless Vector Control Of PMSLM Based On Extended Adaptive Sliding Mode Observer

The permanent magnet synchronous linear motor(PMSLM)is widely used in military field and private enterprises with high dynamic response,high precision and high efficiency.Among them,the dynamic installation of mail conveying system in large postal logistics sorting yard is permanent magnet synchronous linear motor.In PMSLM vector control system,the speed and position angle of the movers are the key to complete the feedback of closed-loop control,but the need for additional position encoder and other hardware will increase the cost of the control system.Especially,the expensive linear position sensor greatly increases the cost of the mechanical and electrical control system,especially in the logistics center with large linear motor.For this kind of low profit industry,it is very meaningful to design a PMSLM sensorless control system with high robustness and easy to realize,so as to reduce the cost of use and improve the competitiveness of products.Based on the comprehensive comparison of the existing control systems without position,the paper designs an extended adaptive sliding mode observer,which verifies the correctness of the whole control system from three aspects: theoretical basis,simulation trial and experimental test.The main research work of this paper is as follows:(1)Based on the motor operation mechanism and FOC theory,and considering the side effect of linear motor,the mathematical model of PMSLM is established in d-q coordinate system.The simulation model of PMSLM vector control system is created on matlab/simulink,and the system model is tested to be of good performance.(2)In order to solve the problem of symbol function buffeting and low pass filter phase lag of traditional sliding mode position estimation observer,ASMO is adopted to solve the problem.On this basis,the extended adaptive sliding mode observer(EASMO)is proposed to solve the problem that the estimation accuracy of the dynamic position is affected by the amplitude change of the EMF in ASMO.Simulation results show that EASMO can effectively suppress chattering,phase compensation and high accuracy of position estimation,and achieve robust and fast response control compared with traditional sliding mode observer control.(3)According to the hardware part design,it is mainly divided into the driving board and control board of PMSLM control system.In view of the software program design,this paper uses tms320f28335 dsp digital signal processing chip to program PMSLM vector control system,and focuses on the programming of EASMO module and interrupt main function.(4)Build the PMSLM vector control system platform and complete the experimental verification.The theoretical analysis,simulation and experimental results show that the PMSLM position free control system based on EASMO can realize the accurate operation of constant speed and variable speed by magnetic field directional control,which is suitable for the situation with compression cost requirements and stable operation.