| 摘要 |
PURPOSE:To obtain rotary torque having no torque ripple by reading the accurate sine wave information stored in a memory in synchronism with the magnetic field from a rotor magnet and digitally processing it and driving the brushless DC motor. CONSTITUTION:Digital information is read from ROM31, 41 storing accurate sine wave signal digital information sampled at the number of samplings relative to the magnetic field of the rotor magnet and the repetition number per revolution of the rotor of a rotor revolution speed corresponding signal FG from a frequency generator 51 in accordance with the outputs from counters 32, 42 for counting the pulses PFG. The read information through an oscillator 82 servo controlled by a signal FG, a counter 83, digital comparators 84S, 84C, inhibit gates 85S, 85C and flip-flops 81S, 81C is converted into pulse width modulation signals PWS, PWC, and the signals PWS, PWC are inputted through switching circuits 66, 76 in synchronism with the magnetic field signals ES, EC from the hall elements 61, 71 into driving circuits 100, 110 respectively. |
