The Vector Control Of Permanent Magnet Synchronous Motor Based On Speed Sensorless At Full Speed Range

Permanent magnet synchronous motor(PMSM),with high power density,simple maintenance,high reliability,had been widely used in AC speed regulating system.In order to realize high-performance vector control of synchronous motor,it must obtain accurate of the motor rotor position.In the traditional AC speed control system,usually using the rotary transformer,photoelectric encoder to detect the position,which would increase the complexity of the system and maintenance costs due to the introduction of mechanical sensors.Therefore,in order to overcome the shortage of mechanical sensors,speed sensorless technology has become a hot spot in the field of motor control.Firstly,the paper introduced the research status and trend of the speed sensorless technology of PMSM.The algorithm of zero speed,low speed,medium and high speed velocity sensor control was compared and analyzed,and the motor mathematical model was deduced under different coordinate systems.Secondly,on the basis of id=0,the rotor position was estimated by using the pulsating high-frequency voltage injection method and sliding mode observer.At low speed,the pulsating high-frequency voltage injection method based on the motor rotor salient pole effect was adopted,which could not only insensitive to the parameters of the motor,but also did not depend on the fundamental wave equation of the motor.This method accurately estimate the rotor position,but could not effectively track the dynamic process of the system because of multiple filters resulting at high-speed At the middle and high speed,the phase locked loop(PLL)was proposed to estimate the rotor position for the estimation of the jitter and hysteresis of the rotor position by the traditional sliding mode observer.Instead of the symbol function,the Sigmoid function and gain method was introduced,which effectively improved the estimate performance of the traditional sliding mode observer.The smooth transition of pulsating high-frequency voltage injection method to sliding mode observer method was realized by weighted average switching.Finally,the simulation model of the sensorless control system was built on the Matlab/Simulink software.The simulation results show that the proposed method can switch between two algorithms without fluctuation.In order to further verify the practicality of the project,the no-load and loading experiments were carried out on the hardware experiment platform.The experimental results show that the performance of the motor is excellent under the rotor composite estimation,with certain practical value in engineering.