Method for operating a resonant power converter

• US 8,174,851 B2
• Filed: 06/15/2007
• Issued: 05/08/2012
• Est. Priority Date: 06/20/2006
• Status: Expired due to Fees

• Current Assignee: Signify Holding B.V. (Signify N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Elferich, Reinhold
• Primary Examiner(s): Berhane, Adolf
• Assistant Examiner(s): Finch, III, Fred E
• Application Number:
  US12/302,898
• Publication Number:
  US 20090316442A1
• Time in Patent Office: 1,789 Days
• Field of Search: 363/17, 363/21.02, 363/21.03, 363/89
• US Class Current: 363/21.02
• CPC Class Codes: H02M 1/0032 Control circuits allowing low power mode operation, e.g. in standby mode
• CPC Class Codes: H02M 3/33592 having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary side of an isolation transformer
• CPC Class Codes: H02M 3/3376 with automatic control of output voltage or current
• 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

According to an exemplary embodiment a method of operating a resonant power supply comprises controlling the resonant power supply in a discontinuous way. According to an exemplary embodiment a resonant power supply comprises a first switching element, and at least one energy storing element, wherein the resonant power supply is adapted to be controlled in a discontinuous way.

Claims

1. A method of operating a resonant power supply comprising a first switching element, a resonant circuit, including a transformer, connected to an output of the first switching element, and a rectifier having an input side connected to an output of the transformer and an output side for delivering output power to a load;

the method comprising;

discontinuously switching the first switching element; and

initializing a standby operation by transferring energy to the first switching element from at least one energy storing element provided at the output side of the rectifier; and

soft-switching the first switching element.

2. The method according to claim 1, wherein the soft-switching is a zero voltage switching.

3. The method according to claim 1, wherein the rectifier comprises a second switching element and wherein the resonant power supply further comprises an output filter including the at least one energy storing element, wherein the energy is transferred from the at least one energy storing element to the first switching element by switching the second switching element.

4. The method of claim 3, wherein immediately prior to switching the second switching element, no energy is stored in the resonant circuit.

5. The method according to claim 1, further comprising controlling a switching operation of the resonant power supply to have a Resonant State Commutation phase.

6. The method according to claim 5, wherein, during the Resonant State Commutation phase, a current flowing through the resonant power current is reversed.

7. The method according to claim 5, further comprising increasing an output power of the resonant power supply by applying a power pulse, wherein the controller switches the first switching device for the power pulse.

8. The method according to claim 7, wherein the power pulse is inserted after the Resonant State Commutation phase.

9. The method of claim 5, wherein the Resonant State Commutation phase corresponds to half of a period of a resonant frequency of the resonant circuit.

10. The method according to claim 1, further comprising controlling a switching operation of the resonant power supply to have a Zero State Return phase.

11. The method according to claim 10, wherein in the Zero State Return phase an initial state of the resonant power supply is recovered.

12. The method according to claim 10, wherein, during the Zero State Return phase, the energy transferred in the initialization is substantially returned to the at least one energy storing element.

13. A resonant power supply, comprising:

a first switching element;

a resonant circuit including a transformer, the resonant circuit being connected to an output of the first switching element;

a rectifier having an input side connected to an output of the transformer and an output side for delivering output power to a load;

at least one energy storing element provided at the output side of the rectifier; and

a controller configured to control a switching operation of the first switching element to be discontinuous,

wherein the resonant power supply is configured to transfer energy initializing a standby operation from the at least one energy storing element to the first switching element in such a way that the first switching is soft switched.

14. The resonant power supply of claim 13, wherein the rectifier comprises a second switching element and wherein the resonant power supply further comprises an output filter including the at least one energy storing element, wherein the controller is configured to control a switching operation of the second switching element to initialize the energy transfer from the at least one energy storing element to the first switching element.

15. The resonant power supply according to claim 14, wherein the rectifier is a synchronous rectifier.

16. The resonant power supply according to claim 14, further comprising:

a second output filter, wherein the resonant power supply is adapted to supply both output filters during the standby operation.

17. The resonant power supply of claim 14, wherein the controller controls an operation of the second switching element such that immediately prior to switching the second switching element, no energy is stored in the resonant circuit.

18. The resonant power supply of claim 14, wherein the controller controls the switching operations of the first and second switching elements to produce a repetitive pattern or four phases comprising a Zero State phase, immediately followed by a Standby Initialization phase, immediately followed by a Resonant State Commutation phase, immediately followed by a Zero State Return phase,

wherein the first and second switching devices are switched during the Standby Initialization phase and the Zero State Return phase,

wherein during the Zero State phase no energy is stored in the resonant circuit,

wherein during the Standby Initialization phase the energy is transferred to the first switching element from the at least one energy storing element connected to the output side of the transformer;

wherein during the Resonant State Commutation phase, a current flowing through the resonant power supply experiences a reversal in direction; and

wherein during the Zero State Return phase, the energy transferred in the Standby Initialization phase is substantially returned to the at least one energy storing element.

19. The resonant power supply according to claim 13, wherein the resonant power supply is an LLC-converter comprising a half-bridge or a full-bridge.

20. A method of operating a resonant power supply comprising a first switching element, a resonant circuit, including a transformer, connected to an output of the first switching element, and a rectifier having an input side connected to an output of the transformer and an output side for delivering output power to a load;

the method comprising;

controlling the resonant power supply to operate with a repetitive pattern or four phases comprising a Zero State phase, immediately followed by a Standby Initialization phase, immediately following by a Resonant State Commutation phase, immediately followed by a Zero State Return phase,

wherein the first switching device is switched during the Standby Initialization phase and the Zero State Return phase,

wherein during the Zero State phase no energy is stored in the resonant circuit,

wherein during the Standby Initialization phase energy is transferred to the first switching element from at least one energy storing element provided at the output side of the rectifier;

wherein during the Resonant State Commutation phase, a current flowing through the resonant power supply experiences a reversal in direction; and

wherein during the Zero State Return phase, the energy transferred in the Standby Initialization phase is substantially returned to the at least one energy storing element.