| 摘要 |
<p>Power factor is increased and harmonic distortion is decreased in a boost circuit by varying the current drawn in phase with the ripple voltage from a rectifying bridge. The boost circuit includes a series connected inductor (21) and switching transistor (Q1) and the control electrode of the switching transistor is connected to a second inductor (26). The second inductor is magnetically coupled to the first inductor and provides feedback for sustaining high frequency oscillations in the boost circuit. A third inductor (51) is magnetically coupled to the first and second inductors and to the control electrode of the switching transistor. The voltage from the third inductor is rectified (53) and filtered (55) to remove the high frequency pulses but not the ripple and the voltage is coupled (56, Q2) to the control electrode of the switching transistor for changing the power consumed by said boost circuit in phase with the ripple.</p> |
