| 摘要 |
PURPOSE:To obtain a rotary torque adapted for the brushless DC motor without torque ripple by reading an accurate sine wave information, stored in a memory in synchronism with the magnetic field of a rotor magnet, modulating it into pulse signal and driving the brushless DC motor therewith. CONSTITUTION:Digital information is read from ROMs 21, 31 storing accurate sine wave signal digital information sampled by the repetition number per one revolution of a rotor 1 of the rotor revolving speed corresponding signal FG from a frequency generator 41 and sampling number relating to the magnetic field of the rotor magnet in accordance with the outputs from counters 22, 32 for counting the pulses PFG. The read information is obtained through flip-flops 71S, 71C reset by the output from the oscillator 76 and set by the output of the counter 73 for counting the output of the oscillator 72. The read information is converted into pulse width modulation signals PWS, PWC having repetition frequency of the oscillated output of the oscillator 76, and is thus inputted to the drive circuits 80, 90 through switches 55, 65 switched in synchronism with the magnetic signals ES, EC from Hall elements 51, 61. |
