| 摘要 |
PURPOSE:To accurately and speedily decide that a constant speed has been reached, in an electric motor speed controlling system controlled so that the rotational speed is proportioal to the frequency of a reference signal, by detecting the coincidence of the sampled values of the deviations between the frequencies of the reference signal and the feedback signal. CONSTITUTION:In a control system for the electric motor rotational speed or the like, the phase difference between the frequency of the reference pulse applied as a speed instruction and that of the feedback pulse generated according to the number of revolutions of an electric motor is detected, and a driving current according to the phase difference is supplied in order to control the electric motor speed omega so as to be a constant speed omega0 proportional to the frequency of the reference pulse. To decide that the motor has reached a constant-speed state after rising, the deviations between the frequencies of the reference pulse signal and the feedback pulse signal are sampled. Said sampling cycle is made shorter than 1/2 of the shortest oscillation cycle in the transient state, (t1 t3, t3 t4), and the deviations are read more than 3 times, (Pa.Pb.Pc). By deciding a constant speed state from the coincidence thereof, an accurate and speedy decision is made possible. |
