Study On Sensorless Full Speed Range Control Of Surface Mounted Permanent Magnet Synchronous Motor

Permanent magnet synchronous motors(PMSM)are widely used in industrial and civil systems beacaus of its high efficiency,high power density and high power factor.As an important parameter of PMSM,rotor position is not only used for magnetic field orientation,but also for calculating speed and providing real-time speed to motor driver.Traditional permanent magnet synchronous motor(PMSM)obtains rotor position mainly by mechanical sensors such as photoelectric encoder and resolver.However,mechanical sensors not only increase the cost of the system,but also make the motor system more complex and increase the axial length of the rotor,which is not conducive to the use and maintenance of the motor.In order to solve the disadvantageous factors brought by mechanical sensors,sensorless control technology of permanent magnet synchronous motor(PMSM)is proposed and widely concerned.In this paper,the surface mounted permanent magnet synchronous motor(SPMSM)is taken as the research object to study the speed sensorless control in full speed range.A new method of initial rotor position estimation,virtual voltage vector injection method,is proposed.Based on the deduced principle of virtual voltage vector injection method,the initial rotor position of SPMSM can be estimated experimentally.Firstly,this paper summarizes the structure classification of PMSM and the development history and status quo of its control technology,and gives a detailed introduction to the existing sensorless control strategy of PMSM.Secondly,the mathematical models of PMSM in stator three-phase static coordinate system,two-phase static coordinate system and rotor synchronous coordinate system are established,respectively.The Vector Control principle and SVPWM modulation principle of PMSM are elaborated in detail.Finally,the control method of id=0 is selected to build the simulation model,and the control performance of vector control system of PMSM is simulated and verified.Thirdly,the sensorless control principle of high frequency voltage injection method,which is commonly used in low speed control of SPMSM,is deduced.Because the estimation process of high frequency voltage injection method is complex and there are filtering and modulation processes in the initial rotor estimation process,a new method of rotor initial position estimation,voltage vector injection method,is proposed,and the proposed method is also discussed.Subsequently,the principle of MRAS method for high-speed control in SPMSM is deduced,and the performance of model reference adaptive control at low-speed and high-speed is analyzed.By weighting method,the estimated rotor speed and position information are combined to make the speed transition from low-speed to high-speed smoothly.Finally,a simulation model is built in Matlab/Simulink to simulate the full speed range of SPMSM.Sensorless control is simulated and verified.Finally,an experimental platform for rotor initial position estimation based on virtual voltage vector injection is built,including hardware and software parts of the experimental platform.The experimental results of the proposed virtual voltage vector injection method for SPMSM initial position detection verify the accuracy and feasibility of the proposed virtual voltage vector injection method for estimating the initial position of the rotor.