POWER FACTOR CORRECTION CIRCUIT

• US 20150062986A1
• Filed: 02/27/2014
• Published: 03/05/2015
• Est. Priority Date: 09/02/2013
• Status: Active Grant

• Current Assignee: LSIS Co. Ltd. (LS Corporation)
• Original Assignee: LSIS Co. Ltd. (LS Corporation)
• Inventors: PARK, Chan Gi, LEE, Jae Ho, JIN, Ho Sang
• Granted Patent: US 9,337,721 B2
• Time in Patent Office: Days
• US Class Current: 363/89
• CPC Class Codes: H02M 1/0085 Partially controlled bridges
• CPC Class Codes: H02M 1/4208 Arrangements for improving power factor of AC input
• CPC Class Codes: H02M 1/4225 using a non-isolated boost converter
• CPC Class Codes: H02M 7/062 Avoiding or suppressing excessive transient voltages or currents
• CPC Class Codes: H02M 7/125 Avoiding or suppressing excessive transient voltages or currents
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

Provided is a power factor correction circuit correcting a power factor of AC voltage. The power factor correction circuit includes: a rectifying unit stopping rectifying the AC voltage in a transient state and generating an rectified voltage by rectifying the AC voltage in a steady state; a power factor correction unit generating a power-factor-corrected voltage by correcting the rectified voltage; a smoothing unit generating a smoothed voltage by smoothing the power-factor-corrected voltage; and an inrush current limiting unit providing a limited current by limiting an inrush current generated by the AC voltage in the transient state and stopping providing a current to the smoothing unit.

Claims

1. A power factor correction circuit correcting a power factor of AC voltage, comprising:

a rectifying unit stopping rectifying the AC voltage in a transient state and generating an rectified voltage by rectifying the AC voltage in a steady state;

a power factor correction unit generating a power-factor-corrected voltage by correcting the rectified voltage;

a smoothing unit generating a smoothed voltage by smoothing the power-factor-corrected voltage; and

an inrush current limiting unit providing a limited current by limiting an inrush current generated by the AC voltage in the transient state and stopping providing a current to the smoothing unit.

2. The circuit of claim 1, further comprising a current control signal generation unit controlling a current flow to the inrush current limiting unit according to whether the power factor correction circuit is in a steady state by generating a current control signal controlling the rectifying unit and the inrush current limiting unit.

3. The circuit of claim 2, wherein the current control signal generation unit generates the current control signal on the basis of a value of the power-factor-corrected voltage applied to one end of one capacitor or a plurality of capacitors connected in parallel.

4. The circuit of claim 3, wherein the current control signal generation unit prevents a current flow to the inrush current limiting unit by determining that the power factor correction circuit is in a steady state when a value of the smoothed voltage is equal to or greater than a reference voltage value.

5. The circuit of claim 4, wherein the current control signal generation unit allows a current flow to the inrush current limiting unit by determining the power factor correction circuit is in a transient state when the value of the smoothed voltage is less than the reference voltage value.

6. The circuit of claim 1, wherein the inrush current limiting unit comprises a silicon controlled rectifier (SCR) and the rectifying unit comprises an SCR.

7. The circuit of claim 6, wherein the current control signal generation unit generates a control signal when the power factor correction circuit is in a steady state to turn off the SCR in the inrush current limiting unit and turn on the SCR in the rectifying unit.

8. The circuit of claim 6, wherein the current control signal generation unit generates a control signal when the power factor correction circuit is in a transient state to turn on the SCR in the inrush current limiting unit and turn off the SCR in the rectifying unit.

9. A power factor correction circuit comprising:

a plurality of bridge diodes;

a power factor correction unit having an input terminal connected to an output terminal of the plurality of bridge diodes;

a smoothing capacitor having one end connected to an output terminal of the power factor correction unit;

a switch having one end to which AC voltage is applied;

a diode having one end connected to the other end of the switch;

a register having one end connected to the other end of the diode; and

a current control signal generation unit turning on the switch in a transient state and preventing a current from flowing into two upper bridge diodes among the plurality of bridge diodes to allow the register to provide a limited size of current to the smoothing capacitor.

10. The circuit of claim 9, wherein the current control signal generation unit generates a current control signal on the basis of a voltage value applied to one end of the smoothing capacitor connected to an output terminal of the power factor correction unit.

11. The circuit of claim 10, wherein the current control signal generation unit determines that the power factor correction circuit is in a transient state when a voltage value applied to one end of the smoothing capacitor connected to the output terminal of the power factor correction unit is less than a reference voltage value.

12. The circuit of claim 9, wherein the switch and the diode are SCRs.

13. A method of operating a power factor correction circuit correcting a power factor of AC voltage, the method comprising:

determining whether the power factor correction circuit is in a transient state;

limiting an inrush current generated by the AC voltage when the power factor correction circuit in the transient state;

generating a rectified voltage by rectifying the AC voltage when the power factor correction circuit is in a steady state;

generating a power-factor-corrected voltage by power-factor-correcting the rectified voltage; and

generating a smoothed voltage by smoothing the power-factor-corrected voltage.

14. The method of claim 13, further comprising controlling whether to limit the inrush current according to whether the power factor correction circuit is in a steady state by generating a current control signal.

15. The method of claim 14, wherein the controlling whether to limit the inrush current comprises generating the current control signal on the basis of a value of the power-factor-corrected voltage applied to one end of one capacitor or a plurality of capacitors connected in parallel.

16. The method of claim 15, wherein the determining of whether the power factor correction circuit is in the transient state comprises determining that the power factor correction circuit is in a steady state when a value of the smoothed voltage is equal to or greater than a reference voltage value.

17. The method of claim 16, wherein the determining of whether the power factor correction circuit is in the transient state comprises determining that the power factor correction circuit is in the transient state when the value of the smoothed voltage is less than the reference voltage value.

18. The method of claim 13, wherein the limiting of the inrush current comprises using a first SCR and the generating of the rectified voltage comprises using a second SCR.

19. The method of claim 18, wherein the generating of the rectified voltage by rectifying the AC voltage comprises:

turning off the first SCR; and

turning on the second SCR.

20. The method of claim 18, wherein the limiting of the inrush current comprises:

turning on the first SCR; and

turning off the second SCR.