Research On The Method Of Vector Control And Field Weakening Of PMSM

Permanent magnet synchronous motor (PMSM) has the advantage of smaller volume, higher efficiency and higher power density over the induction motor. Therefore PMSM is applied more and more in the small and medium-sized capacity of the motion control system since the1980s with the development of microcomputer technology, power electronic technology and the use of the rare earth permanent magnet materials. At the same time, the research on the performance of PMSM system has entered a new stage.Space voltage vector control technology is the basic of vector control and flux weakening control technology, its principle is deeply studied in this paper, various parts of simulation model is built in Matlab/SimuLink, which lays a foundation for later simulation of vector control system and flux weakening control technology.The vector control system of PMSM is studied, mainly including coordinate transformation theory, mathematical model under dq coordinate system and vector control theory, based on this, the simulation model of vector control system is built. The correctness of vector control theory is verified by simulation results which including dynamic and static performance of start, speed adjusting and load disturbance, etc.The gradient descent algorithm is used for field-weakening in this paper based on deeply study of field-weakening technology of PMSM. Among them, the division of field weakening region, the determination of stator current reference under dq coordinate, the modification of current reference in different field weakening regions and the choice of coefficient in modification are deeply studied; the simulation model of field-weakening system is built on the basis of the simulation model of vector control system, the feasibility of the control method is verified by simulation results of dynamic and static performance in field weakening region, which lays a foundation for realization of follow-up system.In terms of the realization of software and hardware of experimental system, CAN-USB communication circuit is designed on the experimental platform based on digital signal processing (Digital signal processing, DSP) chip TMS320F2812which have already existed in laboratory in order to facilitate debugging program, the communication program of PC computer and DSP is written by VB and C language respectively, the data exchange and processing between PC computer and DSP is realized, program debugging is greatly facilitated.Initial positioning of the rotor, make sure that it can quickly go to system settings from anywhere in the starting position;Commissioning the current inner ring of the system, make the feedback of the quadrature axis component of current tracking a given value by adjusting the parameters of the PI adjuster, At the same time tested the stator current, motor can meet the condition of constant amplitude after stability.