Study on speed detection and control method of PMSM under ultra-low speed

The mathematical model of permanent magnet synchronous motor (PMSM) and the digital control method of current loop have been studied, including P regulator, P regulator plus feed forward control and PI regulator. And PI has the best performance. Under ultra low speed, the coupling of d axis current and q axis current do not exist, so the speed control system become a single input and single output system. The speed detection problem of PMSM has been studied also in this paper. The method of T and M/T speed detection will deteriorate the performance of the servo system under ultra-low speed. The M method is suitable for high speed and low speed range both. The deference of PLL and M speed detection method has been studied also. System software flowchart using TMS320F2812 is presented. The experiment results are given, and the validity of this theory is proved.