| 摘要 |
PURPOSE:To eliminate the torque loss and abnormal vibration of a brushless motor by controlling via a switching mode power source the collector vs. emitter voltage so that an output transistor may always have the prescribed current amplification factor capable of being predetermined by a reisitor. CONSTITUTION:Assume that the only transistor Q1 of output transistors Q1-Q3 is conducted by the positional relation between a rotor 1 and an armature winding 3. Since the hFE of the Q1 varies in response to the collector vs. emitter voltage VCE, the VCE of the Q1 when the loop gain of a negative feedback loop via a differential amplifier 13, a low pass filter 14, a switching mode power source 15, windings L1, Q1, and resistor 7 are sufficiently high are automatically determined, the hFE of the Q1 becomes constant. When the torque command voltage varies, the emitter current of the Q1 alters, and the VCE of the Q1 is automatically varied. Since the hFE of the Q1 is maintained at constant value, the Q1 is not saturated, but maintains the operating state of minimum power consumption. |
