The invention provides a control method of an approximately-discrete fate
terminal sliding mode of a PMSM speed regulating
system. The control method comprises the steps of firstly receiving the main command of angular rate, extracting the motor
angular velocity feedback, and calculating the first-order derivative of speed error; secondly calculating the fast
terminal sliding mode surface of a speed ring and the
electric current loop command of a speed regulating
system; thirdly calculating the
electric current loop controlled variable by means of
angular acceleration feedback, collecting
line current and calculating the A-axis and D-axis current of PMSM under dq coordinate and the first-order variable quantity of the error, and calculating the fast
terminal sliding mode surface of the dq coordinate
electric current loop; lastly completing
motor control by using the calculated electric
current loop dq coordinate
voltage controlled variable as the input of adverse park transformation of PMSM. The invention is advantageous in that the control robustness of the
servo-actuated speed regulating
system is improved, the control method is not sensitive to the change of the motor parametric and external moment interference, and the system's
adaptive capacity to environment is enhanced; the speed ring and the electric
current loop control item both adopt integration to conduct
smoothing on sliding mode variable structure switching phase, and the control chattering of conventional linear sliding mode can be prevented.