POWER FACTOR CORRECTION CIRCUIT FOR A POWER ELECTRONIC SYSTEM

• US 20150364989A1
• Filed: 06/13/2014
• Published: 12/17/2015
• Est. Priority Date: 06/13/2014
• Status: Active Grant

• Current Assignee: City University of Hong Kong
• Original Assignee: City University of Hong Kong
• Inventors: Chung, Shu Hung Henry, Yuen, Kuen Faat, Fan, Wing To
• Granted Patent: US 10,177,646 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02M 1/0045 Converters combining the concepts of switch-mode regulation and linear regulation, e.g. linear pre-regulator to switching converter, linear and switching converter in parallel, same converter or same transistor operating either in linear or switching mode
• CPC Class Codes: H02M 1/007 Plural converter units in cascade push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826
• CPC Class Codes: H02M 1/12 Arrangements for reducing harmonics from ac input or output
• CPC Class Codes: H02M 1/4225 using a non-isolated boost converter
• 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

A power factor correction circuit for a power electronic system comprising a series-pass device arranged to control an input characteristic of a power converter, and a control mechanism arranged to control an operation of the series-pass device during a power conversion process, so as to increase a power factor of the power electronic system and/or to reduce a harmonic distortion generated by the power converter to an electrical current supplied by a power source in the power electronic system.

Claims

1. A power factor correction circuit for a power electronic system comprising:

a series-pass device arranged to control an input characteristic of a power converter; and

a control mechanism arranged to control an operation of the series-pass device during a power conversion process, so as to increase a power factor of the power electronic system and/or to reduce a harmonic distortion generated by the power converter to an electrical current supplied by a power source in the power electronic system.

2. A power factor correction circuit for a power electronic system in accordance with claim 1, wherein the input characteristic of the power converter includes an input current waveform of the power converter.

3. A power factor correction circuit for a power electronic system in accordance with claim 1, wherein the series-pass device is connected in series with an input of the power converter.

4. A power factor correction circuit for a power electronic system in accordance with claim 1, wherein the series-pass device is a bipolar junction transistor.

5. A power factor correction circuit for a power electronic system in accordance with claim 1, wherein the series-pass device is arranged to operate in an active region of a current-voltage characteristic of the series-pass device.

6. A power factor correction circuit for a power electronic system in accordance with claim 5, wherein an operating point of the series-pass device is regulated at boundaries between an active region and a saturation region of a current-voltage characteristic of the series-pass device.

7. A power factor correction circuit for a power electronic system in accordance with claim 1, wherein the control mechanism is a feedback mechanism arranged to receive an output voltage of the power converter and to generate an input signal for the series-pass device so as to control the input characteristic of the power converter.

8. A power factor correction circuit for a power electronic system in accordance with claim 7, wherein the feedback mechanism includes a first error amplifier arranged to compare the output voltage of the power converter with a first reference voltage.

9. A power factor correction circuit for a power electronic system in accordance with claim 8, wherein the first reference voltage equals to a predetermined output voltage of the power converter.

10. A power factor correction circuit for a power electronic system in accordance with claim 8, wherein the feedback mechanism further comprises a second error amplifier arranged to compare the input current with a reference input current obtained by multiplying an output of the first error amplifier with a sensed input voltage of the power converter.

11. A power factor correction circuit for a power electronic system in accordance with claim 10, wherein the first error amplifier and/or the second error amplifier is a proportional-plus-integral controller.

12. A power factor correction circuit for a power electronic system in accordance with claim 1, wherein an input capacitor is connected in parallel to the power converter arranged to absorb a high-frequency current pulse generated by the power converter.

13. A power factor correction circuit for a power electronic system in accordance with claim 12, wherein the input capacitor is a film type capacitor

14. A power factor correction circuit for a power electronic system in accordance with claim 1, wherein the input characteristic of the power converter includes an input voltage of the power converter.

15. A power factor correction circuit for a power electronic system in accordance with claim 14, further comprising a voltage controller arranged to sense a voltage across the series-pass device, and to control the input voltage of the power converter.

16. A power factor correction circuit for a power electronic system in accordance with claim 15, wherein the voltage controller includes a voltage comparator arranged to compare the sensed voltage across the series-pass device with a second reference voltage, and to output an error voltage to a switch driver arranged to control the input voltage of the power converter.

17. A power factor correction circuit for a power electronic system in accordance with claim 16, wherein the second reference voltage is slightly greater than a saturation voltage of the series-pass device.

18. A power factor correction circuit for a power electronic system in accordance with claim 16, wherein the switch driver is also arranged to control a switching frequency and/or a duty cycle of the input voltage of the power converter.

19. A power factor correction circuit for a power electronic system in accordance with claim 1, wherein the power converter is a AC-DC converter.

20. A power factor correction circuit for a power electronic system in accordance with claim 1, wherein the power converter is a switching converter.

21. A power factor correction circuit for a power electronic system in accordance with claim 1, wherein the power converter is a boost converter.

22. A power factor correction circuit for a power electronic system in accordance with claim 21, wherein the boost converter operates at a discontinuous conduction mode.

23. A power factor correction circuit for a power electronic system in accordance with claim 1, further comprises a monolithically integrated structure.

24. A power factor correction circuit for a power electronic system in accordance with claim 1, wherein the series pass device is further arranged to filter a noise signal generated by the power converter from reaching the power source of the power electronic system.

25. An electrical power switching converter, comprising:

a switching network arranged to process an input electrical power between an electrical power source and an electrical load;

a power factor correction circuit in accordance with claim 1, wherein the series-pass device is connected in series between an input of the switching network and the electrical power source; and

an output filter connected between the electrical load and the switching network.