Patent ID: 7075193

Claim:
A power factor correction circuit for an uninterrupted power supply, comprising an energy storing branch composed of a first capacitor and a second capacitor in serial, characterized by comprising a first converter having a first inductor, a first switch transistor and a first rectifier element for converting a given positive voltage to a desired positive DC voltage, a second converter having a second inductor, a second switch transistor and a second rectifier element for converting a given negative voltage to a desired negative DC voltage; each of said first and second converters having an input terminal and two output terminals, with said input terminal of each converter connected to the live wire of an AC power supply, said two output terminals connected to the two ends of said energy storing circuit respectively, and the parallel joints of the three acting as output terminals of positive and negative voltages; a common nod of the two capacitors in series of said energy storing branch acting as a common output terminal of positive and negative voltages and connected with the naught wire of said AC power supply; and a controller for controlling the switch transistors of said first and second converters to turn on and off, thereby allowing the input current in the live wire to be consistent with the phase and the waveform of the input voltage.