Non-Contact Rotary Power Transfer System

• US 20100066340A1
• Filed: 12/19/2007
• Published: 03/18/2010
• Est. Priority Date: 12/20/2006
• Status: Active Grant

• Current Assignee: Analogic Corporation
• Original Assignee: Analogic Corporation
• Inventors: Delforge, Adrian C.
• Granted Patent: US 8,581,437 B2
• Time in Patent Office: Days
• US Class Current: 323/305
• CPC Class Codes: A61B 6/035 Mechanical aspects of CT
• CPC Class Codes: A61B 6/56 Details of data transmission or power supply, e.g. use of slip rings
• CPC Class Codes: H01F 2038/143 for signals
• CPC Class Codes: H01F 2038/146 in combination with capacitive coupling
• CPC Class Codes: H01F 38/18 Rotary transformers
• CPC Class Codes: H02J 2310/23 The load being a medical device, a medical implant, or a life supporting device
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/40 using two or more transmitting or receiving devices H02J50/50 takes precedence
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02M 7/53871 with automatic control of output voltage or current
• CPC Class Codes: H05G 1/10 Power supply arrangements for feeding the X-ray tube supply circuits with converters in general H02M; supply circuits for emitters and amplifiers H04B1/16 - H04B1/1623

Abstract

A power delivery system includes a rotary transformer having a primary winding and a secondary winding and configured to transfer power between stationary coupling elements on a stationary side and rotational coupling elements on a rotational side. The rotational coupling elements share a central axis with the stationary coupling elements, and are adapted to rotate with respect to the stationary coupling elements. The power delivery system includes an isolation transformer that drives the primary winding of the rotary transformer, and a plurality of power inverter stages whose outputs are adapted to be summed and coupled to the rotary transformer. A plurality of output power converters receive transmitted power from the rotary transformer. A plurality of control elements, disposed on the rotating side, are configured to close a feedback loop on desired and actual performance of the output power converters, and to control the power inverter stages.

Claims

1. A power delivery system, comprising:

a. a rotary transformer having a primary winding and a secondary winding, the rotary transformer configured to transfer power between one or more stationary coupling elements disposed on a stationary side of the rotary transformer and one or more rotational coupling elements disposed on a rotating side of the rotary transformer, the rotational coupling elements sharing a central axis with the stationary coupling elements and being adapted to rotate with respect to the stationary coupling elements;

b. an isolation transformer adapted to drive the primary winding of the rotary transformer;

c. one or more power inverter stages configured to provide input power to the primary winding of the rotary transformer, the power inverter stages having outputs that are adapted to be summed and coupled to the isolation transformer;

d. one or more output power converters configured to receive transmitted power from the rotary transformer and to convert the received power to a desired range for the rotational coupling elements; and

e. one or more control elements disposed on the rotating side of the rotary transformer, the control elements configured to close a feedback loop on desired and actual performance of the output power converters, and further configured to provide to the stationary side of the rotary transformer one or more timing signals to control the power inverter stages.

2. The power delivery system of claim 1, wherein the plurality of power inverter stages comprise modular power inverter stages.

3. The power delivery system of claim 1, wherein the isolation transformer is adapted to drive the primary winding of the rotary transformer in a multi phase configuration.

4. The power delivery system of claim 1, wherein the plurality of power inverter stages are disposed on the stationary side of the rotary transformer, and the plurality of output power converters are disposed on the rotating side of the rotary transformer.

5. The power delivery system of claim 1,

wherein the primary winding of the rotary transformer comprises a plurality of windings housed within a primary housing, and the secondary winding of the rotary transformer comprises another plurality of windings housed within a secondary housing;

and

wherein the primary housing and the secondary housing comprise one or more permeable magnetic cores.

6. The power delivery system of claim 5, further comprising an electrostatic shield configured to shield at least one of the primary housing and the secondary housing.

7. The power delivery system of claim 1, wherein the plurality of power inverter stages comprise a plurality of AC/AC conversion modules configured to independently provide high frequency drive and rectification of the input power to the rotary transformer.

8. The power delivery system of claim 7, wherein the plurality of AC/AC modules are configured to sum their respective outputs onto a magnetic element, and wherein the magnetic element is configured to provide a voltage centered and voltage isolated output to the primary winding of the rotary transformer.

9. The power delivery system of claim 1, wherein the control elements comprise:

a control loop circuit configured to control delivery of power from the secondary winding of the rotary transformer, the control loop circuit disposed on the rotating side of the rotary transformer; and

a gate drive windings coupled to the control loop circuit and configured to transmit real time gate drive waveforms from at least some of the rotational coupling elements to at least some of the power inverter stages.

10. The power delivery system of claim 1, wherein the rotary windings are configured to allow for bi-directional communication between the rotational coupling elements and the stationary coupling elements, by superposition of one or more high frequency signals.

11. The power delivery system of claim 1, further comprising an auxiliary inverter disposed on the stationary side of the rotary transformer and configured to provide auxiliary power to the rotary transformer by a fixed operation of the auxiliary inverter.

12. The power delivery system of claim 11, further comprising:

an auxiliary transformer having a multi-tap winding; and

an auxiliary output regulator disposed on the rotating side of the rotary transformer and configured to regulate the output from those auxiliary transformer windings.

13. The power delivery system of claim 1, further comprising:

independent auxiliary windings in the ring transformer to provide multiple voltage outputs; and

an auxiliary output regulator disposed on the rotating side of the rotary transformer and configured to regulate the output from those auxiliary windings.

14. The power delivery system of claim 1, further comprising an electrostatic discharger configured to substantially prevent static discharge from accumulating on one or more of the rotational coupling elements.

15. The power delivery system of claim 14, wherein the electrostatic discharge comprises at least one of:

a galvanic connection between the stationary side and the rotational side; and

an ionic connection between the stationary side and the rotational side.

16. The power delivery system of claim 1, wherein the windings of the rotary transformer are configured for dual use that allows for bi-directional communication through superposition of one or more coupled high-frequency modulated signals;

and

wherein the dual use comprises a first use in which power signals or timing signals are transmitted through the windings, and a second use that provides for bi-directional communication between the stationary side and the rotational side.

17. The power delivery system of claim 1, wherein the power delivery system is part of a CT (computed tomography) system.

18. The power delivery system of claim 1, wherein the power delivery system is configured to deliver power to an x-ray tube.

19. A device for isolating one or more outputs of a power inverter system from a primary winding of a rotary transformer adapted to couple power between at least one stationary element and at least one rotational element, wherein the power inverter system is configured to provide input power to the primary winding of the rotary transformer, the device comprising:

an isolation transformer configured to receive a sum of the one or more outputs of the power inverter system and to drive the primary winding of the rotary transformer.

20. A method of coupling power between at least one stationary element disposed on a stationary frame and at least one rotational element disposed on a rotational frame and configured to rotate about the stationary element, the method comprising:

summing the outputs of each of a plurality of power inverter stages disposed on the stationary frame;

isolating and shielding the summed output from the primary winding of a rotary transformer;

coupling the isolation transformer to a primary winding of a rotary transformer; and

operating the isolation transformer so that the isolation transformer drives a primary winding of a split rotary transformer configured to receive power from the power inverter stages and to transmit induced power to the rotational elements.

21. A power delivery system, comprising:

a. a rotary transformer having a primary winding and a secondary winding, the rotary transformer configured to transfer power between one or more stationary coupling elements disposed on a stationary side of the rotary transformer and one or more rotational coupling elements disposed on a rotating side of the rotary transformer, the rotational coupling elements sharing a central axis with the stationary coupling elements and being adapted to rotate with respect to the stationary coupling elements;

b. an isolation transformer adapted to drive the primary winding of the rotary transformer;

c. one or more power inverter stages configured to provide input power to the primary winding of the rotary transformer, the plurality of power inverter stages having outputs that are adapted to be summed and coupled to the isolation transformer;

wherein the plurality of power inverter stages comprise a plurality of AC/AC conversion modules configured to independently provide high frequency drive and rectification of the input power to the rotary transformer; and

wherein the plurality of AC/AC modules are configured to sum their respective outputs onto a magnetic element, and wherein the magnetic element is configured to provide a voltage centered and voltage isolated output to the primary winding of the rotary transformer; and

d. one or more output power converters configured to receive transmitted power from the rotary transformer and to convert the received power to a desired range for the rotational coupling elements.

22. A control system for controlling delivery of power by a rotary transformer, the rotary system having a primary winding and a secondary winding and configured to transfer power between stationary coupling elements disposed on a stationary side and rotational coupling elements disposed on a rotating side, the control system comprising:

one or more control elements disposed on the rotating side, the control elements configured to provide timing signals to the stationary side in order to control one or more power inverter stages that provide input power to the primary winding, the control elements including at least one control loop circuit configured to control delivery of power from the secondary winding of the rotary transformer, the control loop circuit further configured to close a feedback loop on desired and actual performance of output power converters that receive transmitted power from the rotary transformer and convert the received power to a desired range for the rotational coupling elements; and

gate drive windings coupled to the control loop circuit and configured to transmit real time gate drive waveforms from at least some of the rotational coupling elements to at least some of the power inverter stages.

24. The electrostatic discharger of claim 22,

wherein the electrostatic discharger comprises at least one of:

a galvanic connection between the rotational coupling elements and the stationary coupling elements; and

an ionic connection between the rotational coupling elements and the stationary coupling elements.

23. An electrostatic discharger for a non-contact power delivery system that is configured to transfer power between one or more stationary coupling elements, and one or more rotational coupling elements configured to rotate with respect to the stationary coupling elements;

wherein the electrostatic discharger is configured to substantially prevent static discharge from accumulating on one or more of the rotational coupling elements.

25. A rotary transformer in a power delivery system that transfers power between stationary coupling elements on a stationary side and rotational coupling elements on a rotational side, the rotary transformer including a primary winding and a secondary winding;

wherein the windings of the rotary transformer are configured for dual use that allows for bi-directional communication through one or more coupled high-frequency modulated signals; and

wherein the dual use comprises a first use in which power signals or timing signals are transmitted through the windings, and a second use that provides for bi-directional communication between the stationary side and the rotational side.