The design of industrial sewing machine servo system based on PMSM

According to the requirements of one industrial sewing machine (ISM) manufacture, a kind of digital servo system for ISM has been designed in this paper. First of all, SVPWM has been analyzed in driving Permanent Magnet Synchronous Machine (PMSM) carefully. Afterwards, a reliable method adopted for both speed and position measurement without photoelectric encoder has been presented. Then, considering about the speed regulating for the servo system, nonlinear PI control algorithm with the control strategy of single closed loop has been proposed. And meanwhile, a ‘Five Steps’ algorithm for needle location of the system has been discussed in detail. At last, with both simulation and test results, the validity and veracity of the control strategies for motor driving, motor speed regulating and needle location of ISM can be proved effectively.