Improved Sliding Mode Observer Sensorless Control Of Permanent Magnet Synchronous Motor With Anti-load Disturbance

Permanent magnet synchronous motor(PMSM)has the advantages of high power density、high reliability and so on,and has become one of the mainstream motors in many industrial applications.It is essential to detect the speed and rotor position in the high-performance PMSM speed control system.The common method is to install position sensor in the motor control system to obtain the rotor position and speed.However,in some extreme temperature environments and strong interference environments,the use of mechanical sensors is restricted.The sensorless control has the advantages of small size、low cost、and suitable for harsh environments.Therefore,the sensorless control technology of PMSM has become a research hotspot in recent years.In PMSM position sensorless control,the sliding mode observer(SMO)uses a discontinuous switching function,which causes serious chattering at the estimated speed.At the same time,the use of low-pass filter(LPF)will bring certain digital delay,resulting in the phase delay problem of the estimated rotor position angle.Aiming at the problem of speed chattering estimated by SMO and phase delay of rotor position angle estimation,this paper studies an improved sliding mode observer(ISMO).The ISMO replace the switching function with a sine saturation function,and introduce a synchronous rotating filter,which can simultaneously reduce estimated speed chattering and phase delay in estimated rotor position angle.In addition,in view of the poor anti-load disturbance performance of position sensorless control of PMSM,a load disturbance observer(LDO)is introduced on the basis of the ISMO,and the estimated load torque is forward-compensated to the controller to improve system performance.In order to prove the feasibility and effectiveness of improved sliding mode observer sensorless control of permanent magnet synchronous motor with anti-load disturbance,the simulation model was built in the MATLAB simulation software Simulink,and the research method was simulated and verified under different working conditions.The control algorithm is written and verified by experiments on a 2.4 kW PMSM.According to the simulation and experimental results,it can be concluded that the improved sliding mode observer sensorless control of permanent magnet synchronous motor with anti-load disturbance studied in this paper,it not only reduces the chattering of the estimated speed,but also effectively reduces the phase delay existing in the estimation of rotor position angle.At the same time,the anti-load disturbance performance of the system is improved.