Resonant converters with an improved voltage regulation range

Patent metadata

Field	Value
Publication number	US-9812977-B2
Application number	US-201514676515-A
Country	US
Kind code	B2
Filing date	Apr 1, 2015
Priority date	Apr 1, 2015
Publication date	Nov 7, 2017
Grant date	Nov 7, 2017

Abstract

A method comprises determining an operating mode based upon an input voltage and an output voltage of a resonant converter, wherein the resonant converter comprises a switch network coupled to an input dc power source, a resonant tank coupled to the switch network and a transformer coupled between the resonant tank and a secondary rectifier, wherein the secondary rectifier is a full-bridge rectifier, configuring the switch network to operate at a buck converter mode in response to a first input voltage and configuring the secondary rectifier to operate at a boost converter mode in response to a second input voltage, wherein the first voltage is higher than the output voltage and the second voltage is lower than the output voltage.

First claim

What is claimed is:

1. A method comprising:
determining an operating mode based upon an input voltage and an output voltage of a resonant converter comprising:
a switch network coupled to an input dc power source and a resonant tank, wherein a transformer is coupled between the resonant tank and a full-bridge secondary rectifier;

configuring the switch network to operate at a buck converter mode by controlling on and off of switches of the switch network;
configuring the full-bridge secondary rectifier to operate at a boost converter mode by shorting a secondary side winding of the transformer;
configuring the switch network to operate at the buck converter mode in response to a first input voltage from the input dc power source; and
configuring the full-bridge secondary rectifier to operate at the boost converter mode in response to a second input voltage from the input dc power source, wherein:
the first input voltage is higher than the output voltage of the resonant converter; and
the second input voltage is lower than the output voltage of the resonant converter.

2. The method of claim 1 , further comprising:
in the buck converter mode, controlling the switches of the switch network based on a phase-shift PWM scheme; and
in the boost converter mode, shorting the secondary side winding of the transformer by turning on two switches of the full-bridge secondary rectifier.

3. The method of claim 1 , further comprising:
in the buck converter mode, controlling the switches of the switch network based on a frequency modulation scheme; and
in the boost converter mode, shorting a secondary side winding of the transformer by turning on two switches of the full-bridge secondary rectifier.

4. The method of claim 1 , further comprising:
in the buck converter mode, controlling the switches of the switch network based on an asymmetric PWM scheme; and
in the boost converter mode, shorting a secondary side winding of the transformer by turning on two switches of the full-bridge secondary rectifier.

5. The method of claim 1 , further comprising:
in the buck converter mode, controlling two bottom switches of the switch network based on a PWM modulation scheme, wherein the switch network is a full bridge; and
in the boost converter mode, shorting a secondary side winding of the transformer by turning on two switches of the full-bridge secondary rectifier.

6. The method of claim 1 , wherein the full-bridge secondary rectifier comprises four switches, and wherein:
a first switch and a second switch are connected in series and further coupled between two terminals of an output capacitor; and
a third switch and a fourth switch are connected in series and further coupled between the two terminals of the output capacitor.

7. The method of claim 6 , wherein:
a secondary side winding of the transformer has a first terminal connected to a common node of the first switch and the second switch, and a second terminal connected to a common node of the third switch and the fourth switch.

8. The method of claim 7 , further comprising:
simultaneously turning on the second switch and the fourth switch to short the secondary side winding of the transformer in the boost converter mode.

9. The method of claim 7 , further comprising:
simultaneously turning on the first switch and the third switch to short the secondary side winding of the transformer in the boost converter mode.

10. A system comprising:
a switching network configured to be connected with an input dc power sourceand operate at a buck converter mode in response to a first input voltage from the input de power source;
a resonant tank coupled between the switching network and a primary side of a transformer; and
a rectifier coupled between a secondary side of the transformer and an output capacitor and configured to operate at a boost converter mode by shorting a secondary side winding of the transformer in response to a second input voltage from the input dc power source, wherein:
the first input voltage is higher than a voltage across the output capacitor; and
the second input voltage is lower than the voltage across the output capacitor.

11. The system of claim 10 , wherein the rectifier is a full-bridge rectifier comprising:
a first switch and a second switch are connected in series and further coupled between two terminals of an output capacitor; and
a third switch and a fourth switch are connected in series and further coupled between the two terminals of the output capacitor.

12. The system of claim 11 , wherein:
the secondary side winding of the transformer has a first terminal connected to a common node of the first switch and the second switch, and a second terminal connected to a common node of the third switch and the fourth switch.

13. The system of claim 11 , wherein:
the second switch and the fourth switch are configured to be simultaneously turned on to short the secondary side winding of the transformer.

14. A method comprising:
enabling a resonant converter that comprising:
a switch network coupled to an input dc power source;
a resonant tank coupled to the switch network; and
a transformer coupled between the resonant tank and a full-bridge secondary rectifier;

in response to an output voltage of the input dc power source, determining an operating mode;
configuring the switch network to operate at a buck converter mode in response to a first input voltage by controlling on and off of switches of the switch network; and
configuring the full-bridge secondary rectifier to operate at a boost converter mode in response to a second input voltage by shorting a secondary winding of the transformer, wherein:
the first input voltage is higher than an output voltage of the resonant converter; and
the second input voltage is lower than the output voltage of the resonant converter.

15. The method of claim 14 , wherein:
the switch network comprises:
a first primary switch and a second primary switch connected in series and further coupled between two terminals of the input dc power source; and
a third primary switch and a fourth primary switch connected in series and further coupled between two terminals of the input dc power source;

a first terminal of a primary winding of the transformer is coupled to a common node of the first primary switch and the second primary switch through the resonant tank;
a second terminal of the primary winding of the transformer is coupled to a common node of the third primary switch and the fourth primary switch;
the full-bridge secondary rectifier comprises four switches, and wherein:
a first switch and a second switch are connected in series and further coupled between two terminals of an output capacitor; and
a third switch and a fourth switch are connected in series and further coupled between the two terminals of the output capacitor;

a first terminal of the secondary winding of the transformer is coupled to a common node of the first switch and the second switch; and
a second terminal of the secondary winding of the transformer is coupled to a common node of the third switch and the fourth switch, and wherein the first terminal of the secondary winding and the first terminal of the primary winding share a same polarity.

16. The method of claim 15 , further comprising:
in the boost converter mode, simultaneously turning on both the second switch and the fourth switch.

17. The method of claim 15 , wherein:
in the boost converter mode, simultaneously turning on both the first switch and the third switch.

Assignees

• Futurewei Technologies Inc

Inventors

• Ye Liming
• Dai Heping
• Fu Dianbo
• Chen Daoshen

Classifications

• Y02B70/1475

  Cross-Sectional Technologies · mapped topic

• H02M2001/0058

  Electricity · mapped topic

• Y02B70/1491

  Cross-Sectional Technologies · mapped topic

• H02M3/33592 Primary

  having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary side of an isolation transformer · CPC title

• Y02B70/1433

  Cross-Sectional Technologies · mapped topic