Power factor correction device

摘要

Disclosed is a PFC (power factor correction) device for shaping an input current of a power converter. The device includes means for receiving a rectified input voltage derived from an AC input voltage; load determining means for determining a load value L which represents the power drawn by a load supplied by the power converter; current shaping means for shaping the input current of the power converter to follow a reference waveform; and control means for controlling the current shaping means to operate over a conduction interval α during each positive and negative half cycle of the AC input voltage. The duration of the conduction interval is controlled in accordance with the load value L. The current shaping means may shape the input current to follow the reference waveform which crosses zero at phase angles which substantially correspond to the start and end of the conduction interval.

主权项

1. A PFC (power factor correction) device for shaping an input current of a power converter, the PFC device comprising:
a receiving module for receiving a rectified input voltage Vrec derived from an AC (alternating current) input voltage VAC; a load determining module for determining a load value L which represents a power drawn by a load supplied by the power converter; a reference determining module for determining a reference offset voltage Voff in accordance with the load value L; a reference waveform module for generating a reference waveform Iref, wherein the reference waveform Iref is proportional to Vrec−Voff; a current shaping module for shaping the input current of the power converter to follow the reference waveform Iref; and a control module for controlling the current shaping module to operate over a conduction interval α, in which the rectified voltage input Vrec is higher than a value substantially equal to said reference offset voltage Voff, during each positive and negative half cycle of the AC input voltage; wherein a duration of the conduction interval α is controlled in accordance with the load value L.