Power converter system and method for operating a power converter system

Patent metadata

Field	Value
Publication number	US-9997996-B1
Application number	US-201715600486-A
Country	US
Kind code	B1
Filing date	May 19, 2017
Priority date	May 19, 2017
Publication date	Jun 12, 2018
Grant date	Jun 12, 2018

Abstract

Techniques for operating a power converter system that includes an LLC resonant converter and a non-inverting buckboost converter that is located in front of the LLC resonant converter are disclosed. In an embodiment, the output voltage of a non-inverting buckboost converter is regulated in response to the input voltage and the output voltage of an LLC resonant converter in order to maintain a desired ratio between the input voltage and the output voltage of the LLC resonant converter. For example, the ratio between the input voltage and the output voltage of the LLC resonant converter is controlled to a desired ratio that matches the turns ratio of the LLC resonant converter's transformer and that may also match (as a second order effect) the ratio of Lr to Lm.

First claim

What is claimed is:

1. A method for operating a power converter system that includes an LLC resonant converter and a non-inverting buckboost converter that is located in front of the LLC resonant converter, the method comprising:
identifying a desired ratio of the input to output voltage of the LLC resonant converter; and
regulating the output of the non-inverting buckboost converter based on the desired ratio of the input to output voltage of the LLC resonant converter;
wherein regulating includes determining a ratio of the input voltage to the output voltage of the LLC resonant converter; and
wherein regulating the output of the non-inverting buckboost converter comprises generating a control signal in response to a comparison of the determined ratio to the desired ratio.

2. The method of claim 1 further comprising regulating the non-inverting buckboost converter in response to a rectified AC mains voltage that is input to the non-inverting buckboost converter.

3. The method of claim 2 further comprising regulating the non-inverting buckboost converter in response to a phase angle of the rectified AC mains voltage.

4. The method of claim 2 further comprising regulating the buckboost converter in response to an amplitude and a phase angle of the rectified AC mains voltage.

5. The method of claim 1 further comprising halting switching of switches within the non-inverting buckboost converter in response to a rectified AC mains voltage that is input to the non-inverting buckboost converter.

6. The method of claim 1 further comprising adjusting a parameter of the LLC resonant converter in response to a comparison between the output of the LLC resonant converter and a reference to regulate the LLC resonant converter.

7. The method of claim 6 wherein adjusting a parameter of the LLC resonant converter comprises adjusting a capacitor voltage of the LLC resonant converter.

8. The method of claim 6 wherein adjusting a parameter of the LLC resonant converter comprises adjusting a frequency of the LLC resonant converter.

9. The method of claim 6 wherein adjusting a parameter of the LLC resonant converter comprises selecting a low power mode when an output of the LLC resonant converter falls below a power level threshold.

10. A method for operating a power converter system that includes an LLC resonant converter and a non-inverting buckboost converter that is located in front of the LLC resonant converter, the method comprising:
identifying a desired ratio of the input to output voltage of the LLC resonant converter; and
regulating the output of the non-inverting buckboost converter based on the output voltage at the LLC resonant converter to maintain the desired ratio of the input to output voltage of the LLC resonant converter;
wherein regulating the output of the non-inverting buckboost converter comprises determining a ratio of the input voltage to the output voltage of the LLC resonant converter; and
wherein regulating the output of the non-inverting buckboost converter comprises generating a control signal in response to a comparison of the determined ratio to the desired ratio.

11. The method of claim 10 further comprising regulating the non-inverting buckboost converter in response to a rectified AC mains voltage that is input to the non-inverting buckboost converter.

12. The method of claim 11 further comprising regulating the non-inverting buckboost converter in response to a phase angle of the rectified AC mains voltage.

13. The method of claim 11 further comprising regulating the buckboost converter in response to an amplitude and a phase angle of the rectified AC mains voltage.

14. A power converter system comprising:
a non-inverting buckboost converter;
an LLC resonant converter; and
a ratio detector to detect a ratio between an input voltage of the LLC resonant converter and an output voltage of the LLC resonant converter and to provide a control signal to the non-inverting buckboost converter;
wherein the non-inverting buckboost converter is configured to regulate the output of the non-inverting buckboost converter based on the control signal and a desired ratio of the input to output voltage of the LLC resonant converter;
further comprising a mode detector to generate a mode control signal in response to a rectified AC mains voltage and an output voltage of the non-inverting buckboost converter.

15. The power converter system of claim 14 wherein the non-inverting buckboost converter is configured to regulate the output of the non-inverting buckboost converter to maintain the desired ratio of the input to output voltage of the LLC resonant converter.

Assignees

• Nxp Bv

Inventors

• Halberstadt Hans

Classifications

• H02M3/33546

  with automatic control of the output voltage or current (H02M3/33561 takes precedence) · CPC title

• G05F1/618

  using semiconductor devices in series and in parallel with the load as final control devices (G05F1/461 takes precedence) · CPC title

• H02M3/1582 Primary

  Buck-boost converters (H02M3/1584 takes precedence) · CPC title

• H02M1/42

  Circuits or arrangements for compensating for or adjusting power factor in converters or inverters · CPC title

• G05F1/62

  using bucking or boosting DC sources · CPC title