LOW-CARRIER-RATIO DEADBEAT CONTROL SYSTEM AND METHOD FOR PMSM

Disclosed are a low-carrier-ratio deadbeat control system and method for a permanent-magnet synchronous motor (PMSM), comprising: the PMSM, an encoder, an abc-dq coordinate transformation unit, a speed outer loop PI controller, a unit for current estimation at 1/2 moment, a current deadbeat controller, a dq-?? coordinate transformation unit, an SVPWM modulation module, and an inverter. During modeling of a current prediction model, the present invention regards the inverter and the motor as a whole for modeling, takes the delay effect of the inverter into consideration, and adds current estimation at 1/2 moment to correct a discretization error, so that the established model is more accurate than the conventional current prediction model; and the present invention adds a current error decoupling and integral compensation module to the deadbeat controller, so that a control static error of a stator current is greatly improved, thus finally realizing good deadbeat control at a low carrier ratio. The results show that the motor speed and the stator current is well controlled, the control static error of the stator current of the motor is relatively small, and the pulsation of output torque is also improved.