Adaptive power converter and related circuitry

• US 8,184,456 B1
• Filed: 08/26/2008
• Issued: 05/22/2012
• Est. Priority Date: 08/26/2008
• Status: Active Grant

• Current Assignee: Infineon Technologies Americas Corp. (Infineon Technologies AG)
• Original Assignee: International Rectifier Corporation (Infineon Technologies AG)
• Inventors: Jain, Praveen K., Agamy, Mohammed S.
• Primary Examiner(s): NGUYEN, MATTHEW VAN
• Application Number:
  US12/198,605
• Time in Patent Office: 1,365 Days
• Field of Search: 363/16, 363/17, 363/20, 363/21.01, 363/21.02, 363 2104- 211, 363/84, 363/89, 363/97, 363/98, 363/131, 363/132, 323/268, 323/271, 323/282, 323/285
• US Class Current: 363/21.02
• CPC Class Codes: H02M 5/29 using discharge tubes only

Abstract

A resonant power converter circuit stage can be configured to: i) receive a rectified voltage derived from an AC input voltage; ii) convert the rectified voltage to an internal voltage based on the application of a duty cycle that varies depending on the input voltage and the output dynamic load, and iii) convert the internal voltage to a DC output voltage for driving the dynamic load based on application of a switching frequency that varies depending on a dynamic load. The efficiency of the power converter system can be increased by setting the internal DC voltage magnitude to be load adaptive. Variation of the internal DC voltage depending on the dynamic load enables the resonant converter circuit to operate at a switching frequency near its optimum resonance frequency. This method results in constant power converter system efficiency over a wide range of loading. In order to further increase the light load efficiency interleaved resonant power converters with load, adaptive internal DC voltage are used.

Claims

1. A method comprising:

receiving an AC input voltage;

based on the AC input voltage, controlling a resonant power converter circuit to produce a DC output voltage to power a dynamic load; and

during generation of the DC output voltage over a range of the dynamic load;

monitoring the AC input voltage;

adjusting a pulse width modulation of a control signal inputted to the resonant power converter circuit to control a setting of an input power factor of the resonant power converter circuit;

monitoring the DC output voltage; and

adjusting a switching frequency of the control signal inputted to the resonant power converter circuit to regulate a magnitude of the DC output voltage within a desired range.

2. The method as in claim 1, wherein adjusting the switching frequency comprises:

monitoring a parameter associated with the dynamic load; and

modifying a magnitude of an internal DC bus voltage of the resonant power converter circuit so that the switching frequency of the resonant power converter circuit operates closer to the optimum resonant frequency of the resonant power converter circuit.

3. The method as in claim 1 further comprising:

monitoring the DC output voltage;

generating an error voltage based on a comparison of a magnitude of the DC output voltage with a reference voltage; and

adjusting the switching frequency based on a magnitude of the error voltage to regulate and maintain the DC output voltage within a voltage range.

4. The method as in claim 1 further comprising:

converting the AC input voltage to an internal DC bus voltage; and

in addition to adjusting the switching frequency of the resonant power converter circuit, adjusting a duration of activating switches of the resonant power converter circuit in a period of the switching frequency to control a magnitude of the internal DC bus voltage, the resonant power converter circuit converting the internal DC bus voltage into the DC output voltage.

5. The method as in claim 1 further comprising:

adjusting a duty cycle of activating switches in the resonant power converter circuit during periods of the switching frequency to control the input power factor associated with the resonant power converter circuit.

6. The method as in claim 5 further comprising:

within multiple periods of the switching frequency, adjusting a duty cycle of activating at least one switch in the resonant power converter circuit to, in turn, produce an internal bus voltage used to derive the DC output voltage.

7. The method as in claim 6, wherein adjusting the duty cycle reduces harmonic content of an input current and a corresponding phase difference between the AC input voltage and corresponding input current used by the resonant power converter circuit to produce the DC output voltage.

8. The method as in claim 1 further comprising:

generating a reference voltage that is substantially in phase with the AC input voltage; and

utilizing the reference voltage to control the input power factor associated with the resonant power converter circuit.

9. The method as in claim 1 further comprising:

converting the AC input voltage into a DC bus voltage, wherein a magnitude of the DC bus voltage of the resonant power converter circuit varies depending on the setting of the input power factor, the resonant power converter circuit converting the DC bus voltage into the DC output voltage.

10. The method as in claim 1, wherein adjusting the switching frequency includes:

adjusting a setting of an internal DC voltage of the resonant power converter circuit depending on a state of the dynamic load, adjustment of the setting of the internal DC voltage causing the switching frequency to operate closer to the resonance frequency of the resonant power converter circuit, the internal DC voltage derived based on power from the AC input voltage.

11. The method as in claim 1 further comprising:

controlling the pulse width modulation of the control signal to adjust an input current of the AC input voltage to be more in phase with the AC voltage.

12. The method as in claim 1 further comprising:

monitoring a phase of the AC input voltage; and

controlling the pulse width modulation of the control signal based on the phase of the AC input voltage.

13. The method as in claim 1 further comprising:

rectifying the AC input voltage;

generating a load adaptive internal DC voltage in the resonant power converter circuit based on the rectified AC input voltage, the load adaptive internal DC voltage causing the switching frequency to operate close to a resonant frequency of the resonant power converter circuit.

14. The method as in claim 1 further comprising:

monitoring an output current supplied by the resonant power converter circuit to the dynamic load; and

adjusting the pulse width modulation of the control signal inputted to the resonant power converter circuit based at least in part on a magnitude of the output current.