Improved sliding mode observer control of surface mounted permanent magnet synchronous motor

In order to solve the chattering problem of permanent magnet synchronous motor sliding mode observer sensorless control system at medium and high speed, an improvement method of using continuous switching control function at zero to replace discontinuous switching control function at zero is proposed, which is combined with approach law control. Taking the phase current and phase voltage of the motor as the input and the speed and rotor position angle as the output, the sliding mode observer was reconstructed and the improved sliding mode observer algorithm is obtained. The surface mounted permanent magnet synchronous motor was selected, and the double closed-loop field oriented vector control method of speed and current was used for simulation and experiment. By comparing the experimental data and results of the improved sliding mode observer, it is concluded that the chattering phenomenon of the traditional sliding mode observer can be reduced by using the continuous switching control function at the zero point or the approach law control method alone. The combination of the two control methods can further reduce the chattering, improve the estimation accuracy of the algorithm, and make the estimated speed and estimated rotor position angle of the motor closer to the actual value. © 2021, Harbin University of Science and Technology Publication. All right reserved.