Single stage resonant power converter with auxiliary power source

• US 7,706,161 B2
• Filed: 03/14/2006
• Issued: 04/27/2010
• Est. Priority Date: 03/14/2006
• Status: Expired due to Fees

• Current Assignee: ABCO Energy, Inc.
• Original Assignee: ABCO Energy, Inc.
• Inventors: Quazi, Fazle S.
• Primary Examiner(s): Tso; Edward
• Assistant Examiner(s): WILLIAMS, ARUN C
• Application Number:
  US11/375,558
• Publication Number:
  US 20070217235A1
• Time in Patent Office: 1,505 Days
• Field of Search: 323/89, 323/205, 323/207, 323/222, 323/319, 315/307, 363/17
• 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 single stage power factor corrected power converter for providing power to a load, comprising:

a smoothing capacitor connected across first and second terminals of a source of DC voltage;

a pair of switching devices connected in series across said first and second terminals of said source of DC voltage, an output line being connected to a 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 first and second terminals of said source of DC voltage 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;

a resonant circuit having a first, second and third terminals and comprising a series connected resonant inductor and an AC blocking capacitor, said resonant circuit being connected at said first terminal to said output line and at said second terminal to said first and second terminals of said source of DC voltage;

a load connected between said third terminal of said resonant circuit and one of said first and second terminals of said source of DC voltage; and

a secondary power source, connected to said resonant circuit for providing an auxiliary source of power to said load near zero crossings of said AC voltage.

2. The single stage power factor corrected power converter of claim 1 wherein said resonant circuit comprises:

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

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

a second terminal of said AC blocking capacitor being connected to said first and second terminals of said source of DC voltage.

3. The single stage power factor corrected power converter of claim 1 wherein said resonant circuit comprises:

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

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

a second terminal of said resonant inductor being connected to said first and second terminals.

4. The single stage power factor corrected power converter of claim 1 wherein said secondary power source comprises:

a secondary winding of said resonant inductor, a first terminal of which is connected to a second of said first and second terminals of said source of DC voltage, for generating a high frequency AC voltage across said secondary winding; and

a rectifying diode having an anode terminal connected to a second terminal of said secondary winding and a cathode terminal connected to second terminal of said resonant circuit, for rectifying said high frequency AC voltage to produce an auxiliary DC power which is applied to said second terminal of said resonant circuit.

5. The single stage power factor corrected power converter of claim 4 wherein said secondary power source further comprises:

a smoothing capacitor connected between said cathode of said rectifying diode and said second of said first and second terminals of said source of DC voltage for smoothing said auxiliary DC power.

6. The single stage power factor corrected power converter of claim 1 wherein said secondary power source comprises:

a diode having an anode terminal connected to said second of said first and second terminals of said source of DC voltage and a first terminal of said load to produce a higher energy flow into said load.

7. The single stage power factor corrected power converter of claim 1 wherein said secondary power source comprises:

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

8. The single stage power factor corrected power converter of claim 7 wherein said secondary power source further comprises:

AC inrush control comprising;

a smoothing capacitor, a first terminal of which is connected to said second of said first and second terminals of said source of DC voltage; and

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

9. The single stage power factor corrected power converter of claim 8 wherein said AC inrush control further comprises:

a second diode, 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.

10. The single stage power factor corrected power converter of claim 8 wherein said AC inrush control further comprises:

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

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

11. The single stage power factor corrected power converter of claim 1 wherein said secondary power source comprises:

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

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

12. The single stage power factor corrected power converter of claim 11 wherein said secondary power source further comprises:

an AC inrush control comprising;

a smoothing capacitor, a first terminal of which is connected to said second of said first and second terminals of said source of DC voltage, and

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

13. The single stage power factor corrected power converter of claim 12 wherein said AC inrush control further comprises:

a second diode, 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.

14. The single stage power factor corrected power converter of claim 12 wherein said AC inrush control further comprises:

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

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

15. The single stage power factor corrected power converter of claim 1 wherein said resonant circuit further comprises:

a resonant capacitor connected between said second terminal of said resonant circuit and said first one of said first and second terminals of said source of DC voltage.

16. The single stage power factor corrected power converter of claim 15 wherein said resonant circuit further comprises:

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

17. The single stage power factor corrected power converter of claim 1 wherein said resonant circuit further comprises:

a resonant capacitor connected between said a winding tap terminal of said resonant inductor and said first one of said first and second terminals of said source of DC voltage.

18. The single stage power factor corrected power converter of claim 1 wherein said resonant circuit further comprises:

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

a resonant capacitor connected between said first terminal of said resonant inductor and said first one of said first and second terminals of said source of DC voltage.

19. The single stage power factor corrected power converter of claim 1 wherein said resonant circuit further comprises:

a secondary winding of said resonant inductor, a first terminal of which is connected to a second of said first and second terminals of said source of DC voltage, for generating a high frequency AC voltage across said secondary winding; and

a resonant capacitor connected between a second terminal of said secondary winding of said resonant inductor and said first one of said first and second terminals of said source of DC voltage.

20. The single stage power factor corrected power converter of claim 1 further comprising:

an electromagnetic interference suppression circuit connected between said source of DC voltage and said pair of switching devices, 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 pair of switching devices 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 single stage power factor corrected power converter of claim 20 wherein said unidirectional device comprises:

a diode 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 first and second terminals of said source of DC voltage.

22. The single stage power factor corrected power converter of claim 1 further comprising:

a load voltage sensor connected between said second terminal of said resonant circuit and said a first of said first and second terminals of said source of DC voltage for measuring the load voltage across said load;

a comparator, 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

an error compensator, responsive to said error voltage, for closed loop control of output DC voltage.

23. The single stage power factor corrected power converter of claim 22 wherein said error compensator comprises:

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

24. The single stage power factor corrected power converter of claim 1 further comprising:

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

a comparator, 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

an error compensator, responsive to said error voltage, for closed loop control of output DC voltage.

25. The single stage power factor corrected power converter of claim 24 wherein said error compensator comprises:

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

26. The single stage power factor corrected power converter of claim 1 further comprising:

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

an error compensator, 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 single stage power factor corrected power converter of claim 1 further comprising:

a DC input voltage sensor connected across said first and second terminals of said source of DC voltage for measuring the DC voltage across said first and second terminals of said source of DC voltage;

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

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

28. The single stage power factor corrected power converter of claim 1 further comprising:

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