Research On Speed Sensorless Control Of Permanent Magnet Synchronous Motor

With the continuous improvement and progress of power electronics technology and AC speed regulation technology,permanent magnet synchronous motor PMSM is widely used in industrial production,transportation and other fields because of its simple structure,good performance and safe and reliable operation.In order to control the motor,it is necessary to accurately measure the speed and position of the rotor in PMSM.In general,mechanical sensors such as photoelectric encoder and Hall sensor are installed on the axis of the motor.However,the installation of mechanical sensors will increase the volume and cost of the system,and improper installation will seriously affect the stable operation of the motor.Therefore,it is particularly important to study the speed sensorless control method of permanent magnet synchronous motor.It estimates the position and speed of the rotor through an algorithm,which fundamentally eliminates the mechanical sensor,thus reduces the size of the motor,reduces the cost,and enables the motor to operate steadily and reliably in some harsh environments.On the basis of summarizing and combing the existing literature,this paper chooses the surface mounted permanent magnet synchronous motor through comparative analysis.The mathematical models of PMSM in different coordinate systems are analyzed,including voltage equation,electromagnetic torque equation and flux linkage equation.It can be seen that PMSM is a high-order,non-linear and strong coupling system.The control method of permanent magnet synchronous motor,especially the vector control method,is studied,because the vector control method can decouple the motor.Finally,the speed sensorless control method ofPMSM in different rotational states is analyzed.Model reference adaptive method is used in low or zero speed state,pulse high frequency voltage injection method is used in medium and high speed state,and the control in full speed range requires the combination of the above two control methods,through transition.The algorithm of weighted average of region achieves its purpose.Through the simulation experiment of MATLAB/Simulink,the data are saved and the waveform is drawn to get the corresponding simulation results,which verifies the feasibility of the control method.