| 摘要 |
<p>A power factor control system (100) for an A.C. induction motor (106) determines the difference in phase between the voltage applied to the motor (106) and the current drawn by the motor (106). Based upon this difference in phase, an integrator (178) generates an error signal. The error signal is compared with a ramp wave to derive a pulse signal which controls the voltage applied to the motor (106), which in turn controls the amount of current supplied to the motor (106), in order to reduce the power consumed by the motor (106). The integrator (178) includes a dual-path feedback filter (192) having a polarized capacitor in each path. A power supply (110) is used to quickly provide the full operating bias voltages required by several of the components contained in the control system (100).</p> |
