Research On Rotation Speed Stability Of AC Permanent Magnet Synchronous Motor

With the rapid development of microprocessor, power electronic and material technology and the gradual improvement of motor manufacturing technology level, Ac servo motor and Ac servo control system will gradually replace the dc servo systems and become the basic measures to realize industrial automation. We are rich in rare earth resources and manufacturing technology of permanent magnet material has got great development; in addition, permanent magnet synchronous motors (PMSM) have excellent performance than other kinds of motors. In view of this, more and more attention has been focused on AC servo control system with PMSM as the executive motor. The paper has done thorough and comprehensive research on full digital AC PMSM servo control system and given the corresponding control strategies aiming at improving the low-speed characteristics of motors.Firstly, this paper presented the mathematical model in three-phase electronic coordinates, two-phase static coordinates and the synchronization reference frame of PMSM vector and set the control mode of id=0.The paper also elaborated vector control technology and the principle and implementation of SVPWM.On this basis, the paper introduced the phase-locked loop technology in order to achieve a wide speed range and stable velocity of the system. The frequency multiplier circuit based on CD4046 resolved the instability problem when motors operated in super low speed. Furthermore, the design of electronic gear improved the stability greatly and enhanced this servo controller adaptability to different motors.Finally, the author described the hardware and software designing on the platform DSP TMS320F2812. Hardware circuits mainly include main circuit, IPM power driver circuit and current/speed/position detecting circuit. According to the modular idea, software program was sub-divided into sectors, including overall design, initialization of rotor position, timer interrupt service program, SVPWM algorithm, speed/position detecting and currents AD conversion, etc. Beyond that, the paper offered some experimental results and the physical maps of control/drive boards.