Research On Sensorless Control System Of Permanent Magnet Synchronous Motor Based On Improved Luenberger Observer

With the rapid development of various technologies,permanent magnet synchronous motors have been applied to many high-demand occasions due to their unique advantages.At this stage,some home appliances,factories,aviation,etc.are pursuing integration,so the sensorless control of PMSM has become a research hotspot.The principle of the conventional sensorless control system is to estimate the rotor speed and position by the variable back EMF in the motor fundamental excitation model.However,this method has obvious disadvantages.When the motor is at low medium speed,the back EMF is small.The signal to noise of useful signals is relatively small and often difficult to extract.To this end,this article takes PMSM as the research object,the main research is as follows:(1)Aimed at the fact that traditional PI speed controllers are susceptible to external disturbances and changes in internal parameters of motors,this paper designs a fast terminal sliding mode speed controller combined with a new reaching rate,and proves the convergence and stability of this method.The simulation results show that the speed response speed of this method is slightly faster than that of traditional PI,the waveform jitter follows and the overshoot is small.When the sudden load is applied,the anti-interference performance of the speed is high,and it can be restored to a stable value in a short time.(2)Pointed at the system with no mechanical sensors,this paper realizes sensorless control based on improved Luenberger observer combined with high frequency voltage injection method.In this paper,the original Luenberger observer structure is improved in two aspects.Additional integral terms are added from stability,and matrix instructions are used as feedforward inputs from rapidity.The simulation results show that the response speed of the optimized system is faster,the overshoot of speed estimation is reduced by 10 r/min,and the position measurement error is 1/5 of the traditional one.(3)In order to improve the dynamic performance of the system in the near future,this paper analyzes the influence of the nonlinearity of the inverter on the signal injection.In order to extract the rotor position information by using the Luenberger observer,the new phase compensation module and the dead time compensation method based on the disturbance observer are proposed respectively to reduce the influence of the dead time of the inverter.Through the comparative analysis,the new phase compensation module is selected to improve the whole system.The simulation results show that the position error after compensation is about 1 / 2 of the original.