Single stage power factor corrected power converter with reduced AC inrush

• US 20070217235A1
• Filed: 03/14/2006
• Published: 09/20/2007
• Est. Priority Date: 03/14/2006
• Status: Active Grant

• Current Assignee: ABCO Energy, Inc.
• Original Assignee: ABCO Energy, Inc.
• Inventors: Quazi, Fazle
• Granted Patent: US 7,706,161 B2
• Time in Patent Office: Days
• US Class Current: 363/89
• CPC Class Codes: H02M 1/425 using a single converter stage both for correction of AC input power factor and generation of a high frequency AC output voltage
• CPC Class Codes: H05B 41/28 using static converters
• 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

The improved single stage power converter circuit topology substantially reduces EMI that is conducted to the AC line, reduces input AC current inrush, improves output ripples by the use of an auxiliary supply near zero crossings of the line AC voltage, provides Power Factors greater than 0.95, provides Total Harmonic Distortions less than 15%, and maintains constant power, including constant power in a non-linear output load. Further, this circuit topology provides output open and short circuit protections by reducing current stress in power components. This topology can also make the power source to appear as a fast-acting variable impedance source, an ideal source for powering an output load that has negative resistance characteristics such as gas discharge lamps.

Claims

1. A control circuit that interconnects an output line to a load, said control circuit being connected to a source of DC voltage, having first and second terminals, said control circuit being powered by a DC voltage applied from said source of DC voltage across a pair of input lines, the control circuit comprising:

smoothing capacitor means connected across said pair of input lines,

a pair of switching devices connected in series across said pair of input lines, said output line being connected to the junction of said pair of serially connected switching devices, there being a switching control associated with the switching devices for switching the switching devices to conduct alternatively between positive and negative ones of said pair of input lines at a predetermined high frequency, there being a finite time between each of the switching during which both of said switching devices are in a non-conductive state;

resonant circuit means having a first, second and third terminals and comprising a series connected resonant inductor means and an AC blocking capacitor means, said resonant circuit means being connected at said first terminal to said output line and at said second terminal to both of said pair of input lines;

load means connected between said third terminal of said resonant circuit means and said a first of said pair of input lines; and

a secondary power source means for providing an auxiliary source of power to said load means near zero crossings of the line AC voltage.

2. The control circuit of claim 1 wherein said resonant circuit means comprises:

resonant inductor means connected at a first terminal to said output line;

AC blocking capacitor means connected at a first terminal to a second terminal of said resonant inductor means; and

a second terminal of said AC blocking capacitor means being connected to both of said pair of input lines.

3. The control circuit of claim 1 wherein said resonant circuit means comprises:

AC blocking capacitor means connected at a first terminal to said output line;

resonant inductor means connected at a first terminal to a second terminal of said AC blocking capacitor means; and

a second terminal of said resonant inductor means being connected to both of said pair of input lines.

4. The control circuit of claim 1 wherein said secondary power source means comprises:

a secondary winding of said resonant inductor means, a first terminal of which is connected to a second of said pair of input lines, for generating a high frequency AC voltage across said secondary winding; and

rectifying diode means having an anode terminal connected to a second terminal of said secondary winding and a cathode terminal connected to a first of said pair of input lines, for rectifying said high frequency AC voltage to produce an auxiliary DC power which is applied to said first one of said pair of input lines.

5. The control circuit of claim 4 wherein said secondary power source means further comprises:

smoothing capacitor means connected between said cathode of said rectifying diode means and said second of said pair of input lines for smoothing said auxiliary DC power.

6. The control circuit of claim 1 wherein said secondary power source means comprises:

diode means having an anode terminal connected to said second of said pair of input lines and a first terminal of said load means to produce a higher energy flow into said load means.

7. The control circuit of claim 1 wherein said secondary power source means comprises:

full bridge high frequency rectifier means, the input terminals of which are connected between a one of said first and said second of said pair of input lines and said second terminal of said resonant circuit means, and the positive and negative output terminals of which are connected to said load means.

8. The control circuit of claim 7 wherein said secondary power source means further comprises:

AC inrush control means comprising;

smoothing capacitor means, a first terminal of which is connected to said second of said pair of input lines; and

diode means, the cathode of which is connected to a second terminal of said smoothing capacitor means and the anode of which is connected to said negative output terminal of said full bridge high frequency rectifier means.

9. The control circuit of claim 8 wherein said AC inrush control means further comprises:

diode means, the cathode of which is connected to said first of said pair of input terminals and the anode of which is connected to said second terminal of said smoothing capacitor means.

10. The control circuit of claim 8 wherein said AC inrush control means further comprises:

wherein said second terminal of said smoothing capacitor means is connected to said first of said pair of input terminals; and

MOSFET means connected between said first terminal of said smoothing capacitor means and said second of said pair of input terminals for regulating current flow to said smoothing capacitor means.

11. The control circuit of claim 1 wherein said secondary power source means comprises:

half bridge high frequency rectifier means, the input terminals of which are connected to a one of said first and said second of said pair of input lines and the positive and negative output terminals of which are connected to said load means; and

first and second series connected high frequency filter capacitors connected across said load means, the junction of said first and said second series connected high frequency filter capacitors being connected to said second terminal of said resonant circuit means.

12. The control circuit of claim 11 wherein said secondary power source means further comprises:

AC inrush control means comprising;

smoothing capacitor means, a first terminal of which is connected to said second of said pair of input lines, and

diode means, the cathode of which is connected to a second terminal of said smoothing capacitor means and the anode of which is connected to said negative output terminal of said half bridge high frequency rectifier means.

13. The control circuit of claim 12 wherein said AC inrush control means further comprises:

diode means, the cathode of which is connected to said first of said pair of input terminals and the anode of which is connected to said second terminal of said smoothing capacitor means.

14. The control circuit of claim 12 wherein said AC inrush control means further comprises:

wherein said second terminal of said smoothing capacitor means is connected to said first of said pair of input terminals; and

MOSFET means connected between said first terminal of said smoothing capacitor means and said second of said pair of input terminals for regulating current flow to said smoothing capacitor means.

15. The control circuit of claim 1 wherein said resonant circuit means further comprises:

resonant capacitor means connected between said second terminal of said resonant circuit means and said first one of said pair of input lines.

16. The control circuit of claim 15 wherein said resonant circuit means further comprises:

secondary resonant inductor means connected in parallel with said resonant capacitor means.

17. The control circuit of claim 1 wherein said resonant circuit means further comprises:

resonant capacitor means connected between said a winding tap terminal of said resonant inductor means and said first one of said pair of input lines.

18. The control circuit of claim 1 wherein said resonant circuit means further comprises:

secondary resonant inductor means connected between said output terminal and said first terminal of said resonant inductor means; and

resonant capacitor means connected between said first terminal of said resonant inductor means and said first one of said pair of input lines.

19. The control circuit of claim 1 wherein said resonant circuit means further comprises:

a secondary winding of said resonant inductor means, a first terminal of which is connected to a second of said pair of input lines, for generating a high frequency AC voltage across said secondary winding; and

resonant capacitor means connected between a second terminal of said secondary winding of said resonant inductor means and said first one of said pair of input lines.

20. The control circuit of claim 1 further comprising:

an electromagnetic interference suppression circuit connected between said source of DC voltage and said basic control circuit, comprising;

a unidirectional device serially connected between said first terminal of said source of DC voltage and a first of said pair of input lines to prevent current from flowing from said basic control circuit to said source of DC voltage; and

a filter capacitor connected across said first and said second terminals of said source of DC voltage.

21. The control circuit of claim 20 wherein said unidirectional device comprises:

diode means having an anode terminal and a cathode terminal, said anode terminal being connected to said first terminal of said source of DC voltage and said cathode terminal being connected to said first of said pair of input lines.

22. The control circuit of claim 1 further comprising:

load voltage sense means connected between said second terminal of said resonant circuit means and said a first of said pair of input lines for measuring the load voltage across said load means;

comparator means, responsive to said load voltage and a reference voltage, for generating an error voltage indicative of the difference between said load voltage and said reference voltage; and

error compensation means, responsive to said error voltage, for closed loop control of output DC voltage.

23. The control circuit of claim 22 wherein said error compensation means comprises:

resonant circuit control means for modulating the operating frequency of said resonant circuit means.

24. The control circuit of claim 1 further comprising:

resonant circuit current sense means for generating a load voltage indicative of a sum of current through said AC blocking capacitor means and said output load current;

comparator means, responsive to said load voltage and a reference voltage, for generating an error voltage indicative of the difference between said load voltage and said reference voltage; and

error compensation means, responsive to said error voltage, for closed loop control of output DC voltage.

25. The control circuit of claim 24 wherein said error compensation means comprises:

resonant circuit control means for modulating the operating frequency of said resonant circuit means.

26. The control circuit of claim 1 further comprising:

output load power sense means for generating a load voltage indicative of an output load current and an output load voltage; and

error compensation means, responsive to said output load voltage, for providing a feedback signal to said switching control for closed loop control of said output power.

27. The control circuit of claim 1 further comprising:

input voltage sense means connected across said pair of input lines for measuring the input voltage across said input lines;

comparator means, responsive to said input voltage and a reference voltage indicative of a predetermined maximum value of said input voltage, for generating an error voltage indicative of the difference between said input voltage and said reference voltage; and

switching circuit control means for modulating the operating frequency of said pair of switching devices to maintain the predetermined maximum value of said input voltage.

28. The control circuit of claim 1 further comprising:

wherein said switching circuit control means is responsive to an output short circuit condition when the impedance of said load means approaches zero and the inductor energy in said resonant circuit means rapidly increases said input voltage, for increasing said operating frequency in order to maintain the predetermined maximum input voltage value.