Research On Sensorless Position Identification And Control For PMSM

In the PMSM vector control system,the rotor position signal acquisition is a necessary condition,usually using mechanical sensors to detect rotor position information,some high temperature,high corrosive occasions are not suitable for mechanical sensor applications.this paper for the realization of PMSM sensorless wide speed range of the control,carried out the following aspects of the study:First of all,this paper establishes a surface-mount PMSM vector control system based on rotor field orientation and control.Secondly,the sliding mode variable structure control theory is introduced,and the sliding mode observer is designed to detect the position and speed of the rotor by observing the back electromotive force.In order to solve the problem of high frequency jitter of sliding mode observer,this paper introduces the saturation function to replace the switching function,and designs the phase locked loop to replace the traditional arctangent function to reduce the angle estimation error.When the motor is running at zero or low speed,the back electromotive force is very small,so the low speed down mode observer method dynamic performance is not ideal.Considering the dynamic performance of the high-frequency voltage injection method in the low-speed operation of the motor,this paper focuses on the operation effect of the high-frequency voltage injection method at the low speed of the motor.On this basis,the weighting coefficient method Synchronous motor without sensor composite control,that is,the motor running at low speed,the use of pulse high frequency voltage injection method,with the speed of the gradual change to the sliding mode observer method to detect the motor rotor position.Finally,the simulation based on Maltlab / Simulink is carried out on the pulse frequency high voltage voltage injection method and the compound control method.The simulation results show that the sensorless composite control method proposed in this paper is suitable for both low speed and high speed.The experimental results verify the feasibility of the method.