OPTIMIZATION OF A POWER CONVERTER EMPLOYING AN LLC CONVERTER

• US 20130003430A1
• Filed: 06/28/2011
• Published: 01/03/2013
• Est. Priority Date: 06/28/2011
• Status: Active Grant

• Current Assignee: Acleap Power Incorporated
• Original Assignee: Lineage Power Corporation (GE Aerospace)
• Inventors: Reddy, Raghothama
• Granted Patent: US 8,681,513 B2
• Time in Patent Office: Days
• US Class Current: 363/74
• CPC Class Codes: H02M 1/0058 by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero using an auxiliary actively switched resonant commutation circuit connected to an intermediate DC voltage or between two push-pull branches of an inverter bridge H02M7/4811; in resonant inverters H02M7/4815; in inverters operating from a resonant DC source H02M7/4826
• 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 3/01 Resonant DC/DC converters
• CPC Class Codes: H02M 3/33571 Half-bridge at primary side of an isolation transformer
• CPC Class Codes: H02M 3/33573 Full-bridge at primary side of an isolation transformer
• CPC Class Codes: H02M 7/217 using semiconductor devices only
• 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 converter includes an input stage connected to receive an input signal and to provide an intermediate DC voltage, and an output stage having an LLC converter connected to receive the intermediate DC voltage and to provide a DC output voltage. Additionally, the power converter includes a control unit connected to the input and output stages to regulate the DC output voltage and set a target operating parameter of the LLC converter based on controlling the intermediate DC voltage. A method of operating a power converter is also provided.

Claims

1. A power converter, comprising:

an input stage connected to receive an input signal and to provide an intermediate DC voltage;

an output stage having an LLC converter connected to receive the intermediate DC voltage and to provide a DC output voltage; and

a control unit connected to the input and output stages to regulate the DC output voltage and set a target operating parameter of the LLC converter based on controlling the intermediate DC voltage.

2. The power converter as recited in claim 1 wherein the DC output voltage is regulated by a pulse frequency modulation (PFM) signal or a pulse width modulation (PWM) signal applied to the LLC converter.

3. The power converter as recited in claim 1 wherein the target operating parameter determines an operating frequency or an operating period of the LLC converter.

4. The power converter as recited in claim 3 wherein the target operating parameter corresponds to a series resonant frequency of the LLC converter.

5. The power converter as recited in claim 3 wherein the target operating parameter corresponds to a higher operating frequency of the LLC converter than its series resonant frequency.

6. The power converter as recited in claim 5 wherein the higher operating frequency of the LLC converter corresponds to a maximum series operating frequency selected from a group of LLC converters.

7. The power converter as recited in claim 1 wherein a minimum series resonance frequency determined by an upper component tolerance of an LLC converter corresponds to a lower end of a target frequency window of LLC operating frequencies.

8. The power converter as recited in claim 1 wherein a maximum series resonance frequency determined by a lower component tolerance of an LLC converter corresponds to an upper end of a target frequency window of LLC operating frequencies.

9. The power converter as recited in claim 1 wherein a minimum value of the intermediate DC voltage based on a tolerance distribution of sample units is sufficient to provide a maximum series resonant frequency of the LLC converter.

10. The power converter as recited in claim 9 wherein the tolerance distribution of sample units provides a range of about five percent for the intermediate DC voltage.

11. A method of operating a power converter, comprising:

receiving an input signal and providing an intermediate DC voltage;

generating a DC output voltage from an LLC converter having an input coupled to the intermediate DC voltage; and

regulating the DC output voltage and setting a target operating parameter of the LLC converter based on controlling the intermediate DC voltage.

12. The method as recited in claim 11 wherein the DC output voltage is regulated by a pulse frequency modulation (PFM) signal or a pulse width modulation (PWM) signal applied to the LLC converter.

13. The method as recited in claim 11 wherein the target operating parameter determines an operating frequency or an operating period of the LLC converter.

14. The method as recited in claim 13 wherein the target operating parameter corresponds to a series resonant frequency of the LLC converter.

15. The method as recited in claim 13 wherein the target operating parameter corresponds to a higher operating frequency of the LLC converter than its series resonant frequency.

16. The method as recited in claim 15 wherein the higher operating frequency of the LLC converter corresponds to a maximum series operating frequency selected from a group of LLC converters.

17. The method as recited in claim 11 wherein a minimum series resonance frequency determined by an upper component tolerance of an LLC converter corresponds to a lower end of a target frequency window of LLC operating frequencies.

18. The method as recited in claim 11 wherein a maximum series resonance frequency determined by a lower component tolerance of an LLC converter corresponds to an upper end of a target frequency window of LLC operating frequencies.

19. The method as recited in claim 11 wherein a minimum value of the intermediate DC voltage based on a tolerance distribution of sample units is sufficient to provide a maximum series resonant frequency of the LLC converter.

20. The method as recited in claim 19 wherein the tolerance distribution of sample units provides a range of about five percent for the intermediate DC voltage.