摘要 |
PURPOSE:To reduce the variation of torque and speed by applying a sinusoidal voltage to the exciting coil of a brushless motor. CONSTITUTION:A brushless motor 1 is equipped with an encoder 2, and its control block is composed of DC converter 11, a speed comparator 12, a ROM 9, a multiplier 8, a current sensor 13, a current comparator 7, a PWM pulse generator 4 and a driver 3. Then, the difference between the preset rotational speed command signal of said motor 1 and a speed signal detected by the encoder 2 is outputted as a speed deviation signal by the speed comparator 12, and is multiplied by a reference sinusoidal signal at the multiplier 8 to output a sinusoidal speed deviation signal. Further, a sinusoidal pulse signal is generated by a PWM pulse generator 4 in the basis of a current deviation signal by the current comparator 7 and applied to the exciting coil of said brushless motor 1 via the driver 3. |