METHOD FOR CALCULATING SPEED ESTIMATED VALUE IN SPEED CONTROL SYSTEM

A method for calculating a speed estimated value in a speed control system, comprises the steps of: (a) storing the number of speed detection pulses obtained at each interval of a speed control process and time that the speed detection pulse was obtained; (b) calculating a detection speed from the number of latest speed detection pulses and its detection time, and the number of the previously stored speed detection pulses and its detection time; (c) executing an averaging process of motor model output corresponding to time that the detection speed was obtained; (d) obtaining a difference between an output obtained at said step (c) and the detection speed; (e) executing a calculation of a load torque estimation by multiplying the difference of the step (d) by an observer gain; (f) executing an estimation of a motor speed for next processing from the difference of the step (d) and a difference between the detection speed and the motor model output; (g) calculating an output of a speed amplifier by constituting the speed amplifier by a proportion element and from a speed estimated value obtained in the step (f); (h) obtaining a torque command by summing the speed amplifier and the load torque estimated value; and (i) outputting the torque command of the step (h) at a start point of the next speed control interval. Therefore, an output time of the torque command becomes clear, and the estimated value of the motor speed at a correct time can be obtained.