Research And Realization Of Variable Frequency Drive System Of Permanent Magnet Synchronous Motor

With the continuous development of material technology,permanent magnet synchronous motor(PMSM)using permanent magnet as rotor has been more and more widely studied and applied.It has the advantages of simple structure,high efficiency and high reliability.In this paper,permanent magnet synchronous frequency conversion drive system is studied,using AC-DC-AC converter to control the motor.Because of the full-control rectifier used in the front stage,it can effectively improve the harmonic characteristics and power characteristics of the system,reduce the impact of harmonics on the grid,and realize the two-way flow of electric energy,and improve the utilization of energy.Firstly,the control method of PWM rectifier in operation is analyzed,and its model expression is derived.On this basis,the double closed-loop control method which satisfies the stability control is analyzed,and the specific process of parameter calculation is given.The principle and implementation method of SVPWM algorithm are introduced in detail.Finally,the simulation model is built based on MATLAB simulation software for simulation and verification.Then,the control method of PMSM in operation is analyzed,and the model expression is deduced.In order to simplify the control,the coordinate transformation process of the model expression is deduced.The different operation control methods are studied,and the id-0 control method which is more suitable for this paper is selected after summarizing and comparing.The double closed-loop control strategy of PMSM based on PI controller is analyzed,and the calculation method of PI controller parameters is given.Finally,the simulation model is built to verify the operation control method of PMSM.Moreover,the high frequency pulse voltage injection method is used to establish the motor model expression.Based on the analysis process,the current component is studied,and the judgment method of rotor position based on DC offset is obtained.Finally,the whole structure of the variable frequency drive system of PMSM is analyzed and designed,and the design methods of its main circuit,control circuit and control program are given.Based on the designed test platform,the detection method of the initial position of permanent magnet synchronous motor and the frequency conversion drive control system are tested and analyzed.