Research And Design Of PMSM Servo System Based On DSP

With the development of motor control technology, power electronics technology and Digital Signal Processor (DSP), the AC servo system can already achieve the speed performance comparable to that of DC servo system, and it also has the advantages of simple structure, reliable operation and higher efficiency. Compared with the induction motor, Permanent Magnet Synchronous Motor (PMSM) not only has the advantages of high power factor, low inertia, no excitation loss and wide speed range, but also can be simply controlled and has favorable control performance. Suppoted by the test equipment renovation project of my unit, this subject studies and designs a PMSM speed servo system based on DSP, Which is used on the test equipment for the automatic transitional device of DF diesel locomotives, to replace the existing DC drive system.At first, the thesis introduces the background and importance of the research on the subject, discusses the developing situation of the AC servo system and related fields at home and aboard. After introducing coordinate transformation, the mathematical model of PMSM is established in dq coordinate system and the rotor field-orientated vector control theory with isd=0strategy is analyzed. Then the fundamentals of Space Vector Pulse Width Modulation (SVPWM) and the implementation of the seven-segment SVPWM waves are described in detail. Next, the simulation model of the PMSM vector control system is established in MATLAB/Simulink and simulation is carried out, simulation results verify the correctness of relevant theory and the feasibility of the real system, and show that the PMSM vector system is fairly good in performance.After principle analysis and simulation, the thesis elaborates the design of the hardware and software of the PMSM speed servo system. The hardware, which adopts TMS320LF2407A DSP of TI as its control core, includes a DSP control board, a power driver board and a signal processing board. The software includes the main routine, the Timer1(T1) underflow interrupt service routine and the Capture3(CAP3) interrupt service routine, the program is written in assembly language. In addition, the traditional method to initialize the PMSM rotor position by magnetic force is improved. Finally, the test for the whole system is carried out and the test results, which are briefly analyzed and explained, are given. The test results show that the performance of the system can meets the requirements for the test equipment for the automatic transitional device of DF diesel locomotives.