Reserch Of Novel AC Servo System Based On DSP

With the widely use of Permanent Magnet Synchronous Motor(PMSM), the study on PMSM servo system has become an inevitable trend and has huge theoretical significance and practical application value. This paper uses the TI's Digital Signal Processor(DSP)LF240A as the core processor of the motor servo system. Design and develop the hardware and software of the position sensorless PMSM vector control servo system. Simulation by Matlab and parameter optimization have been done, and the debug of software and hardware platform also have been done.Firstly, after presenting the background of the project and some knowledge of servo system ,deeply study the theory of vector control on PMSM and the mathematical model of PMSM. Based on the model, the position sensorless PMSM vector control servo system is discussed. The control block diagram is presented.Secondly, SVPWM and SMO(sliding mode observer) are thoroughly discussed. Also, an improved phase-compensation strategy is proposed to minimize the unwanted phase lag mostly introduced by sliding mode observer's low pass filter, which is robust to unknown paramter variation .The sliding mode observer structure and its compensation method are described. To show the validity of the proposed control scheme, simulations are carried out and the results are analyzed at last.Thirdly, the main structures of the software and hardware are introduced. The main functional blocks are illuminated. To the hardware, each part of the control circuit and the design and debugging of the peripheral circuits are thoroughly discussed. The control software has been programmed with C and assemble language. Position sensorless PMSM dual close-loop vector control with feedback of speed and current are realized. The flow charts of main program and PWM interrupt service routine are given. The important control strategies of position sensorless PMSM vector control such as voltage sensing, current sensing, SMO rotor position estimation, speed calculation, generation looking-up table of sine and cosine, vector coordinate transformation, PI regulators, SVPWM vector modulation algorithm are all accomplished in the PWM interrupt service routines. All the parameters and variables in the program have been scalled.Lastly, the program is debugged in the IDE of CCS2000. after setting the parameters of the program, Experiments has been carried out on the software and hardware platform, and the experimental results are also given. It's proved that the SVPWM algorithm and the startup scheme without current loop work well , but till now the characteristic of system even with position sensor is not so good, so the position sensorless scheme is not successful.In the conclusion and prospects, there is a list of finished work and advices for further work.