Controlling capacitive snubber as function of current in inverter

• US 9,431,921 B2
• Filed: 05/01/2012
• Issued: 08/30/2016
• Est. Priority Date: 05/01/2012
• Status: Active Grant

• Current Assignee: Analogic Corporation
• Original Assignee: Analogic Corporation
• Inventors: Quigley, Stephen J.
• Primary Examiner(s): Kim, Jung
• Assistant Examiner(s): Yeshaw, Esayas
• Application Number:
  US13/461,270
• Publication Number:
  US 20130293008A1
• Time in Patent Office: 1,582 Days
• Field of Search: 363/131, 307/11, 307/151
• US Class Current: 1/1
• CPC Class Codes: H02M 1/34 Snubber circuits
• CPC Class Codes: H02M 1/342 Active non-dissipative snubbers
• CPC Class Codes: H02M 7/44 by static converters
• CPC Class Codes: H02M 7/4815 Resonant converters H02M7/4811 and H02M7/4826 take precedence
• CPC Class Codes: H02M 7/5387 in a bridge configuration
• 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

One or more systems and/or techniques are provided for electrically coupling and/or decoupling a capacitive snubber component to/from an inverter as a function of a current in the inverter. A current sensing component may be configured to measure the current in the inverter and/or determine whether the current in the inverter exceeds a desired threshold. The desired threshold may be set at a value sufficient to reset the capacitive snubber component. When the current in the inverter is above the desired threshold, the capacitive snubber component may be coupled to the inverter. When the current in the inverter is below the desired threshold, the capacitive snubber component may be decoupled from the inverter. In this way, little to no energy stored in the capacitive snubber component may be dissipated in the inverter when the current in the inverter drops below a level sufficient to reset the capacitive snubber component.

Claims

1. An inverter, comprising:

a resonant circuit comprising;

a capacitor;

an inductor; and

a transformer comprising a winding having a first terminal connected to the capacitor and a second terminal connected to the inductor;

a snubber arrangement comprising;

a capacitive snubber component; and

a switching component coupled in series with the capacitive snubber component and configured to electrically couple the capacitive snubber component to the resonant circuit and to electrically decouple the capacitive snubber component from the resonant circuit based upon a current of an electrical signal through the resonant circuit; and

a second switching component coupled in parallel with the snubber arrangement.

2. The inverter of claim 1, comprising a current sensing component configured to determine whether the current of the electrical signal is greater than a threshold,

the switching component configured to electrically couple the capacitive snubber component to the resonant circuit when the current of the electrical signal is greater than the threshold and to electrically decouple the capacitive snubber component from the resonant circuit when the current of the electrical signal is less than the threshold.

3. The inverter of claim 2, the current sensing component comprising a transformer.

4. The inverter of claim 2, the current sensing component comprising a hall effect sensor.

5. The inverter of claim 2, the current sensing component comprising a timing component configured to time at least one of the coupling of the capacitive snubber component to the resonant circuit and the decoupling of the capacitive snubber component from the resonant circuit.

6. The inverter of claim 5, the timing component comprising a flip-flop component.

7. The inverter of claim 1, the switching component comprising a switch configured to be open when the current of the electrical signal is less than a threshold, causing the capacitive snubber component to be electrically decoupled from the resonant circuit, and configured to be closed when the current of the electrical signal is greater than the threshold, causing the capacitive snubber component to be electrically coupled to the resonant circuit.

8. The inverter of claim 7, the threshold a function of a value of the current that resets the capacitive snubber component.

9. The inverter of claim 1, the capacitive snubber component configured to extend a transitional period of the electrical signal from a first voltage to a second voltage.

10. The inverter of claim 1, the inverter comprising a series resonant inverter.

11. The inverter of claim 10, the series resonant inverter configured for a peak output power of between about 10 kW and about 90 kW and an average output power of between about 2 kW and about 10 kW.

12. The inverter of claim 1, the inverter configured to output power, at least some of the output power supplied to a radiation source of a radiology modality that is electrically coupled to the inverter.

13. The inverter of claim 1, comprising a second snubber arrangement comprising:

a second capacitive snubber component; and

a third switching component configured to electrically couple the second capacitive snubber component to the resonant circuit and to electrically decouple the second capacitive snubber component from the resonant circuit based upon the current of the electrical signal through the resonant circuit.

14. The inverter of claim 13, comprising a fourth switching component coupled in parallel with the second snubber arrangement.

15. A method for selectively coupling a capacitive snubber component to a resonant circuit of an inverter, comprising:

measuring a current of an electrical signal through the resonant circuit,

electrically coupling the capacitive snubber component to the resonant circuit when the current of the electrical signal is greater than a threshold; and

electrically decoupling the capacitive snubber component from the resonant circuit when the current of the electrical signal is below the threshold.

16. The method of claim 15, the threshold a function of a value of an electrical current that resets the capacitive snubber component.

17. The method of claim 15, the inverter comprising a series resonant inverter.

18. The method of claim 15, the inverter configured to output a peak power that is at least five times an average power output by the inverter.

19. The method of claim 18, the inverter configured to output a peak power of at least 40 kW.