Research on Low Speed Operation of PMSM Based on Improved Non-Singular Fast Terminal SMC

A non-singular fast terminal sliding mode control (SMC) strategy with a new piecewise reaching law (PRL) of permanent magnet synchronous motor is presented to reduce the steady-state buffeting in this paper. A speed adaptive regulator is designed to make the motor work stably at the lowest speed value under the limitation of the DC bus voltage condition when the motor starts non-normally or with locked rotor, and a disturbance observation is introduced to further improve the anti-interference ability of the control system. The experiment test is carried out. Compared with the experimental results of traditional SMC, the buffeting suppression of the control system using non-singular fast terminal SMC with PRL is reduced by 66.7%, 57.9% and 60% at 20 rpm, 30 rpm and 40 rpm under no-load condition, respectively. The buffeting suppression and the dynamic stability time of the proposed method are reduced by 52.3% and 53.3% under load condition, respectively.