Research On Field Weakening Control Systcem Of Hybrid Permanent Magnet Synchronous Motor

Permanent magnet synchronous motor(PMSM)has the advantages of high efficiency,high power factor and high reliability.But there also exists the shortage of poor field weakening performance.Improving the field weakening performance and broadening the scope of speed control of PMSM have been research focus for a long time.Rotor magnetic system of hybrid PMSM is made up of permanent magnet ring which is axially magnetized and iron core between two permanent magnet rings.Air gap and excitation magnetic potential of hybrid PMSM is small,and its magnetic resistance of the armature magnetic field circuit is small,so the demagnetization effect is obvious.Three-phase hybrid PMSM with good field weakening performance is the research object of this paper.A permanent magnet synchronous motor field weakening control system based on MC56F82748 chip was designed.The field weakening performance of hybrid PMSM was studied on this system.Firstly,this paper introduced the current situation of the development of PMSM and its control theory,introduced the commonly used methods of vector control and promoting field weakening performance.Control methods of the system were selected by comparative analysis of these methods.Secondly,this paper introduced the structure and mathematical model of hybrid PMSM,analyzed the field weakening performance of the hybrid PMSM qualitatively.Then simulation model of hybrid PMSM vector control system was established in MATLAB/Simulink and simulation research was done.Finally,hardware and software design of hybrid PMSM control system based on the MC56F82748 chip was accomplished.Double closed-loop vector control of current and speed based on i_d =0 strategy and field weakening control based on additional voltage feedback method was achieved.4 times of reference speed was realized by field weakening control of the hybrid PMSM.