Research On Sensorless Control Strategy Of Permanent Magnet Synchronous Motor

With the rapid development of Industry 4.0 era,the Internet and industrial production complement each other,and the era of intelligence promotes industrial production.As one of the most common equipment in industrial production,permanent magnet synchronous motor is required to have better performance.However,the Permanent Magnet Synchronous Motor(PMSM)mechanical sensor itself is vulnerable to environmental factors,and has been gradually replaced by the simple Sliding Mode Observer(SMO),However,the estimation accuracy of traditional sliding mode observer is not high,and the observation results are usually mixed with obvious chattering.Taking permanent magnet synchronous motor as the research object,this paper explores the advantages and disadvantages of the observation performance of the traditional sliding mode observer and the improved sliding mode observer,and establishes the permanent magnet synchronous motor experiment platform to explore the optimization effect of the improved sliding mode observer on the control strategy of PMSM,so as to further research the control strategy of PMSM without position sensor.Specific work is as follows:Firstly,this paper describes the research background,research significance and development status of the sensorless control strategy of PMSM,introduces the mathematical model of permanent magnet synchronous motor in detail,analyzes the basic principle of the vector control strategy of permanent magnet synchronous motor in depth,and selects the vector control strategy based on i_d=0 for the research object of permanent magnet synchronous motor.Then,the basic principle and existing problems of sliding mode variable structure control are briefly described,and the traditional sliding mode observer with chattering and poor observation accuracy is improved.Concrete improvement methods:Firstly,the boundary layer variable piecewise compound function is used to replace the sign function in the traditional sliding mode observer,and the sliding mode gain parameter is designed to adapt to the change of current error.Secondly,the variable cutoff frequency low-pass filter is designed to replace the traditional constant cutoff frequency low-pass filter.Finally,the back potential information was observed by the back potential filter,and the observed information was fed back to the equation of state to further optimize the sensorless control strategy of PMSM.The effects of motor parameters on the performance of the sliding mode observer based on Phase Locked Loop(PLL)were also investigated.Finally,in order to explore the optimization effect of permanent magnet synchronous motor control strategy based on the improved sliding mode observer,TMS320F28379 was used as the main control chip to design the system hardware,and the sliding mode control algorithm was optimized and developed based on Code Composer Studio(CCS)software.Then a 6 pole 1kw permanent magnet synchronous motor was used to build the experimental platform of permanent magnet synchronous motor control system,and the software CCS6.2 was used to control PMSM in real time.The experimental results show that the observation accuracy of the improved SMO for motor speed and rotor Angle is higher than that of the traditional SMO,and the inherent chattering problem of the traditional SMO is further weakened by the improved SMO,and the control accuracy of the improved sliding mode observer for permanent magnet synchronous motor is further improved.