System and method for charging and discharging a superconducting coil

• US 7,336,059 B2
• Filed: 11/15/2005
• Issued: 02/26/2008
• Est. Priority Date: 11/15/2005
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Steigerwald, Robert Louis, Garces, Luis Jose
• Primary Examiner(s): Laxton; Gary L.
• Application Number:
  US11/273,984
• Publication Number:
  US 20070108956A1
• Time in Patent Office: 833 Days
• Field of Search: 323/222, 323/225, 323/266, 323/268, 323/271, 323/282, 323/288, 323/350, 323/351, 363/98, 363/132
• US Class Current: 323/288
• CPC Class Codes: H01F 6/006 Supplying energising or de-energising current; Flux pumps
• CPC Class Codes: H02M 1/007 Plural converter units in cascade push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826
• CPC Class Codes: H02M 3/1555 for the generation of a regulated current to a load whose impedance is substantially inductive
• CPC Class Codes: H02M 3/158 including plural semiconductor devices as final control devices for a single load
• CPC Class Codes: H02M 3/3353 having at least two simultaneously operating switches on the input side, e.g. "double forward" or "double (switched) flyback" converter

Abstract

A system and method for charging and discharging a superconducting coil. The system comprising a boost converter coupled between a low-voltage bus and a high voltage bus, and a buck converter coupled between the high-voltage bus and the coil. The system being configured to charge and discharge the coil without reversing the current while reversing polarity, and to only supply high-voltages when necessary. The system further comprising means to dissipate excess energy during discharge. The method comprising pulse width modulating the solid-state switch of a boost converter to achieve a high-voltage from a low-voltage and then switching solid-state switches of a buck regulator to charge or discharge the coil in a non current reversing, polarity reversing manner.

Claims

1. A system for charging and discharging a superconducting coil, comprising:

a boost converter coupled to a low-voltage bus and a high-voltage bus and configured to boost voltage from a low-voltage to a high-voltage;

an energy storage element coupled across the high-voltage bus;

a redundant, two quadrant buck converter coupled to the high-voltage bus, the buck converter including an interface reactor and parallel pairs of solid-state switches and respective flyback diodes; and

,

a controller switching the solid state switches in a non-current reversing, polarity reversing mode to selectively charge the coil from the energy storage element and discharge the coil to the energy storage element.

2. The system of claim 1, wherein the boost converter comprises an inductor and a solid state switch.

3. The system of claim 2, wherein the inductor is coupled in series with a power source and the solid state switch is coupled in parallel with the power source.

4. The system of claim 1, further comprising a braking element coupled in parallel with the coil.

5. The system of claim 4, wherein the braking element comprises a resistor in series with a controllable switch.

6. A system for charging and discharging a superconducting coil, comprising:

a boost converter coupled to a low-voltage bus and a high-voltage bus and configured to boost voltage from a low-voltage to a high-voltage;

an energy storage element coupled across the high-voltage bus;

a low-voltage supply bridge coupled to the low-voltage bus and including a pair of switches and flyback diodes;

a high-voltage booster bridge coupled to the high-voltage bus and to the low-voltage supply bridge and including a pair of solid-state switches and respective flyback diodes; and

a controller switching the pair of switches of the supply bridge and pair of solid state switches of the booster bridge in a non-current reversing, polarity reversing mode to selectively charge the coil from the energy storage element at voltages between the low-voltage and a sum of the low and high-voltages, and discharge the coil to the energy storage element.

7. The system of claim 6, wherein the boost converter comprises an inductor and a solid state switch.

8. The system of claim 7, wherein the inductor is coupled in series with a power source and the solid state switch is coupled in parallel with the power source.

9. The system of claim 7, further comprising a braking element coupled in parallel with the coil.

10. The system of claim 9, wherein the braking element comprises a resistor in series with a controllable switch.

11. A system for charging and discharging a superconducting coil, comprising:

a boost converter coupled to a low-voltage bus and a high-voltage bus and configured to boost voltage from a low-voltage to a high-voltage;

a buck regulator coupled to the boost converter and to the high and low-voltage buses and configured to return energy to a system bus;

an energy storage element coupled across the high-voltage bus;

a low-voltage supply bridge coupled to the low-voltage bus and including a pair of switches and flyback diodes;

a high-voltage booster bridge coupled to the high-voltage bus and to the low-voltage supply bridge and including a pair of solid-state switches and respective flyback diodes; and

a controller switching the pair of switches in the supply bridge and the pair of solid state switches in the booster bridge in a non-current reversing, polarity reversing mode to selectively charge the coil from the energy storage element at voltages between the low-voltage and a sum of the low and high-voltages, and discharge the coil to the energy storage element.

12. The system of claim 11, wherein the boost converter comprises an inductor and a solid state switch.

13. The system of claim 12, wherein the inductor is coupled in series with a power source and the solid state switch is coupled in parallel with the power source.

14. The system of claim 11, further comprising a braking element coupled in parallel with the coil.

15. The system of claim 14, wherein the braking element comprises a resistor in series with a controllable switch.

16. A system for charging and discharging a superconducting coil, comprising:

a dc/dc converter coupled to a low-voltage bus and a high-voltage bus and configured to convert a low-voltage to a high-voltage;

an energy storage element coupled across the high-voltage bus;

a first two quadrant buck converter coupled to the high-voltage bus, the buck converter including a pair of solid-state switches and respective flyback diodes;

a second two quadrant buck converter coupled to the low-voltage bus, the buck converter including a second pair of solid-state switches and respective flyback diodes; and

a controller switching the first and second two quadrant buck converters in a non-current reversing, polarity reversing mode to selectively charge and discharge the coil.

17. The system of claim 16, wherein the dc/dc converter is bi-directional and configured to regenerate the system bus.

18. The system of claim 16, wherein the boost converter comprises an inductor and a solid state switch.

19. The system of claim 18, wherein the inductor is coupled in series with a power source and the solid state switch is coupled in parallel with the power source.

20. The system of claim 16, further comprising a braking element coupled in parallel with the coil.

21. The system of claim 20, wherein the braking element comprises a resistor in series with a controllable switch.

22. A method for charging and discharging a superconducting coil comprising:

pulse width modulating a boost switch to generate a high-voltage from a relatively low-voltage, the boost switch making up part of a boost converter;

switching on both a first and a second solid-state switches of a low-voltage supplier bridge, the low-voltage supplier bridge being coupled to a coil, a low-voltage bus, and a high-voltage booster bridge; and

pulse width modulating a first solid-state switch of the high-voltage booster bridge to charge the coil with a desired voltage, the booster bridge being coupled to a high-voltage bus, a low-voltage bus, and a low-voltage supplier bridge;

switching on a second solid-state switch of the high-voltage booster bridge to discharge the coil in a non-current reversing, polarity reversing manner to an energy storage element which is coupled across the high-voltage bus; and

controlling all switching through control signals from a controller.

23. The method of claim 22, further comprising turing on a discharging solid-state switch while discharging the coil, the discharging solid-state switch being coupled in series with a discharging resistor and in parallel with the energy storage element.

24. The method of claim 22, further comprising turning on braking controllable switch during discharge, the braking thyristor being coupled in series with a resistor and in parallel with the coil.