Research And Design Of Sensorless Control System For Permanent Magnet Synchronous Motor

In recent years,Permanent magnet synchronous motor has many advantages,such as simple structure,small volume,excellent driving performance,high starting torque,high power density.In recent years,it has been widely used in aerospace,industrial robots,new energy vehicles,CNC machine tools,fans and pumps,industrial manufacturing,home appliances and other fields.In practical application,people often use mechanical position sensor to determine the position information of rotor in real time However,in some complex working conditions,mechanical position sensor is easy to be interfered by electromagnetic,noise,temperature and other factors,which greatly reduces the accuracy of detection,and the use of position sensor also increases the economic cost of enterprises.Therefore,it is of great significance to study the position sensorless technology of PMSM.Firstly,in this paper,the method of coordinate transformation is first described,and an ideal PMSM mathematical model is established for decoupling operation.After elaborating several control strategies of the vector control algorithm,we derive the mathematical equation containing the inverse electromotive force according to its mathematical model in the two-phase(stationary)coordinate system,which provides a certain theoretical basis for the design of the sliding-mode observer.Secondly,when the PMSM is running in the middle and high speed area,a new smooth and continuous exponential function is proposed to replace the symbol function SGN(s),which can effectively cut off the chattering of the system,and the normalization processing is added in the phase-locked link to perfect the control system again and increase the accuracy of the rotor position estimation.Then,in the simulation environment of MATLAB / Simulink,the simulation model of PMSM vector control system is established to verify the effectiveness and rationality of the algorithm.Compared with the traditional sliding mode observer,the improved sliding film observer can accurately measure the position and speed of the rotor,which effectively improves the stability and dynamic performance of the system.Thirdly,In order to solve the problem that the rotor position information can't be acquired accurately near the zero and low speed region,the high frequency voltage signal injection method is introduced.Although this control algorithm needs to add a high frequency voltageinput signal generator in the control system,it increases the industrial cost.However,it can solve the problem that the rotor position information can not be obtained accurately near the zero and low speed regions.After the high frequency signal passes through the motor,it carries the rotor position information of the motor,and obtains the useful position signal through the filtering algorithm.Then,it uses PLL technology or position tracking observer to extract the accurate rotor position information.Finally,in order to verify that the algorithm can be applied in practical applications,this paper designs the experimental platform,the design of hardware and software for the control system image,and then the experiment verifies the effectiveness and feasibility of the proposed control method.