Research On High-power Digital AC Servo System

For the past few years, with the development of power electronic technology, micro-electronic technology and motor control theory, the AC servo system has taken the place of DC drive system in various fields. Permanent magnet synchronous motor (PMSM) has the advantage of high power density, simple structure, low intensity noise, high efficiency and wide speed regulation ability without weakening magnetic. And it is widely applied at the area of high precision servo system. So, the research on the control strategies of the PMSM control system has significant meaning.First, the math model of surface mounted permanent magnet synchronous motor (SPMSM) is analyzed. After comparing various control methods, the control method of id=0 rotor flux orientation is selected. And the system simulation model with position loop, speed loop and current loop based on id=0 rotor flux orientation and space voltage vector pulse width modulation (SVPWM) is established at the environment of Matlab/Simulink. The parameters of motor in simulation are the same as actual motor parameters. The modified PI method about permanent magnet synchronous motor vector control system is researched and verified by experiment. The experimental results is consistent to simulation results, indicate that the modified PI method can improve the system dynamic and static performance. The simulation of sudden load on the system, the simulation results show that the SPMSM control system have fast response performance and good anti-jamming performance.Second, the software and hardware of permanent magnet synchronous motor servo control system is designed. The hardware takes TMS320F2812 as the control core, and uses IPM of Mitsubishi as main power circuit. The optically coupled isolation driven circuit, current and bus voltage detection circuit, various protection circuits and serial port communication circuit is designed. The software of servo control system is designed by C language at the environment of CCS3.1. Every function module of servo control is realized with module structural programming. And the current filter, zero compensation, rotor position correction and so on is analyzed and designed detailedly. The running process of main programme and interrupt programme is deeply researched. And the feature of programming and data processing about fix point DSP is introduced detailedly.At last, the software and hardware of servo control system is debugged. Every function modules worked normally. The waveform of open-loop stator current, speed close-loop stator current and line voltage is observed. And the processes of transient and steady state is analyzed when the motor starting, braking and reverse. The effect on servo system working performance in diffent switching frequences is researched. And the software and hardware problems appeared in debugging are researched deeply. And the experiment results have proved the correctness and validity of the designed system.