| 摘要 |
PURPOSE:To obtain a speed control method in which a noise-resistant characteristic is enhanced by a method wherein a position-error signal is created by the logical sum or the logical product of a reference signal and of the positional signal of a motor. CONSTITUTION:A positional-signal detector 4 detects the magnetic flux of a rotor magnet, and it generates a motor positional signal (MS) Si at a duty of 50%. Rotor positional signals C, D as phase switching signals of a motor M are used as the MS Si. Consequently, a position-error signal A becomes a signal which is output once at a cycle of 1/2 of a motor induced-voltage waveform. When the position-error signal A is phase-compensated as a logic signal, a phase-compensated-circuit output signal (PO) B is output so as to be delayed a little. The logical product of the PO B and the rotor positional signals C, D is created, and the motor M is driven. In addition, when a noise enters a reference signal SO, it is output to the position-error signal A and the PO B in an equivalent manner. However, since a period the noise is generated is extremely smaller than a period motor currents Im1, Im2 flow, a change in the speed of the motor M becomes extremely small. |
