Exciter and electronic regulator for rotating machinery
First Claim
1. An exciter assembly for supplying power to a superconducting load disposed within a cryogenic region of a rotating machine, the exciter assembly comprising:
- a transformer having a primary winding and a secondary winding, one of the primary and secondary windings being positioned in a rotational reference frame relative to the other of the primary and secondary windings;
a sensor which provides a control signal indicative of the flow of field excitation current to the superconducting load; and
a current regulator which is disposed in the rotating reference frame and, on the basis of the control signal, regulates the field excitation current to a predetermined value.
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Accused Products
Abstract
An exciter assembly for supplying power to a superconducting load, such as a superconducting field coil, disposed within a cryogenic region of a rotating machine. The exciter assembly provides an efficient and reliable approach for transferring the electrical power energy across a rotating interface and for controlling the ramp up and regulation of field excitation current in the field coil. In particular, the invention provides a controlled recirculation path for current flowing through the field coil. The exciter assembly includes a transformer having a primary winding and a secondary winding, a sensor which provides a control signal indicative of the flow of field excitation current to the superconducting load; and a current regulator which is disposed in the rotating reference frame and, on the basis of the control signal, regulates the field excitation current to a predetermined set. One of the primary and secondary windings is positioned in a rotational reference frame relative to the other of the primary and secondary windings.
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Citations
18 Claims
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1. An exciter assembly for supplying power to a superconducting load disposed within a cryogenic region of a rotating machine, the exciter assembly comprising:
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a transformer having a primary winding and a secondary winding, one of the primary and secondary windings being positioned in a rotational reference frame relative to the other of the primary and secondary windings;
a sensor which provides a control signal indicative of the flow of field excitation current to the superconducting load; and
a current regulator which is disposed in the rotating reference frame and, on the basis of the control signal, regulates the field excitation current to a predetermined value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
a first switching device in series between the secondary winding and the superconducting load;
a second switching device in parallel with the superconducting load and between the first switching device and superconducting load;
a capacitor disposed between the secondary winding and the first switching device and in parallel with the second switching device;
the first switching device being closed when the second switching device is open to provide recharging current to the superconducting load; and
the second switching device being, closed when the first switching device is open to shunt current for recirculation through the superconducting load.
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3. The exciter assembly of claim 2 wherein the first and second switching devices are disposed within the cryogenic region.
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4. The exciter assembly of claim 3 wherein the first and second switching devices are metal oxide semiconductor devices.
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5. The exciter assembly of claim 1 wherein the superconducting load is a superconducting coil including high temperature superconductor.
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6. The exciter assembly of claim 1 wherein the primary winding is in the form of a stationary disk and the secondary winding is in the form of a rotatable disk axially spaced from the stationary disk to form a gap therebetween.
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7. The exciter assembly of claim 6 wherein at least one of the stationary disk and the rotatable disk is formed of radial laminations.
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8. The exciter assembly of claim 1 further comprising
a resistive load; - and
a switch for allowing energy from the superconducting load to flow to the resistive load in the event of a detected fault.
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9. The exciter assembly of claim 1 wherein the transformer is a polyphase transformer driven by a polyphase AC Source.
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10. The exciter assembly of claim 1 wherein the current regulator is disposed in a non-cryogenic environment.
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11. The exciter assembly of claim 10 wherein the current regulator includes:
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a first switching device in series between the secondary winding and the superconducting load;
a second switching device in parallel with the superconducting load and between the first switching device and superconducting load;
a capacitor disposed in parallel between the secondary winding and the first switching device;
the first switching device being closed when the second switching device is open to provide recharging current to the superconducting load; and
the second switching device being, closed when the first switching device is open to shunt current for recirculation through the superconducting load.
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12. The exciter assembly of claim 11 wherein the first switching device is an insulated gate bipolar transistor device and the second switching device is a fast recovery rectifier diode.
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13. The exciter assembly of claim 11 wherein the superconducting load is a superconducting coil including high temperature superconductor.
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14. The exciter assembly of claim 11 wherein the primary winding is in the form of a stationary disk and the secondary winding is in the form of a rotatable disk axially spaced from the stationary disk to form a gap therebetween.
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15. The exciter assembly of claim 14 wherein at least one of the stationary disk and the rotatable disk is formed of radial laminations.
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16. The exciter assembly of claim 10 further comprising:
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a resistive load; and
a switch for allowing energy from the superconducting load to flow to the resistive load in the event of a detected fault.
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17. The exciter assembly of claim 10 wherein the transformer is a polyphase transformer drive by a polyphase AC source.
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18. The exciter assembly of claim 2, further comprising:
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a resistive load; and
a third switching device for allowing energy from the superconducting load to flow to the resistive load in the event of a detected fault.
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Specification