# US 2014/0197710 A1 · Wound field rotating machine with capacitive power transfer

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- Number: US 2014/0197710 A1
- Document ID: US20140197710A1
- Status: Published application
- Kind: A1
- Application number: 14/215,446
- Filed: 2014-03-17
- Published: 2014-07-17
- Earliest claimed: 2011-08-16
- Assignees: Wisconsin Alumni Research Foundation
- Applicants: Wisconsin Alumni Research Foundation
- Inventors: Daniel Colin Ludois; Justin Kyle Reed; Kyle Hanson
- Web page: https://patentgrep.com/patent/US20140197710A1

## CPC

- H02K 13/00: Structural associations of current collectors with motors or generators, e.g. brush mounting plates or connections to windings (supporting or protecting brushes or brush holders in motor casings or enclosures H02K5/14); Disposition of current collectors in motors or generators; Arrangements for improving commutation
- H02K 11/21: Devices for sensing speed or position, or actuated thereby (specially adapted for machines having non-mechanical commutating devices H02K29/06, H02K29/14)
- H02K 13/003: {Structural associations of slip-rings}
- H02K 19/12: characterised by the arrangement of exciting windings, e.g. for self-excitation, compounding or pole-changing
- H02K 19/26: characterised by the arrangement of exciting windings
- B60L 2220/14: Synchronous machines
- Y02E 10/72: Wind turbines with rotation axis in wind direction
- Y02T 10/64: Electric machine technologies in electromobility
- Y02T 90/16: Information or communication technologies improving the operation of electric vehicles
- H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53})
- B60L: PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES (arrangements or mounting of electrical propulsion units or of plural diverse prime-movers for mutual or common propulsion in vehicles B60K1/00, B60K6/20; arrangements or mounting of electrical gearing in vehicles B60K17/12, B60K17/14; preventing wheel slip by reducing power in rail vehicles B61C15/08; dynamo-electric machines H02K; control or regulation of electric motors H02P); SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES (electric coupling devices combined with mechanical couplings of vehicles B60D1/64; electric heating for vehicles B60H1/00); ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL (control or regulation of electric motors H02P); MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

An electrical rotating machine, such as a generator or motor, communicates power from a stationary location to the rotating rotor of the rotating machine via opposed pairs of capacitor plates, one plate of each pair rotating with the rotor and one plate of each pair fixed not to rotate. In one embodiment, separation between the plates of the pair is provided by a cushion of entrapped air.

## Claims

### Claim 1

An electrical rotating machine comprising:
a rotor mounted for rotation about an axis and including at least one electrical coil having a coil axis with a component perpendicular to the axis, the electrical coil comprising a conductor having first and second conductor ends;
at least one first capacitor plate, attached to rotate with the rotor and electrically communicating with the rotor; and
at least one second capacitor plate, mounted to a frame so as not to rotate with the rotor and positioned for capacitive coupling with the first capacitor plate;
wherein the first and second capacitor plates are positioned to transfer power between the electrical coil and a stationary conductor at a range of angular positions of the rotor about the axis.

### Claim 2 (depends on 1)

The rotating machine of claim 1 further including a third capacitor plate attached to rotate with the rotor and electrically communicating with the rotor and a fourth capacitor plate mounted to a frame so as not to rotate with the rotor and positioned for capacitive coupling with respective first and second capacitor plates wherein the third and fourth capacitor plates are positioned to complete a circuit through the coil and the first and second capacitor plates.

### Claim 3 (depends on 2)

The rotating machine of claim 2 wherein the rotor is supported on a shaft extending along the axis and wherein the first and third capacitor plates are conductive cylindrical surfaces coaxial with the shaft and the second and fourth capacitor plates are cylindrical tubes surrounding the cylindrical surfaces.

### Claim 4 (depends on 3)

The rotating machine of claim 3 wherein the cylindrical surfaces and cylindrical tubes provide fluid bearing journals and fluid bearing shafts supporting the rotor during rotation on a cushion of an intervening fluid.

### Claim 5 (depends on 4)

The rotating machine of claim 4 including a nonconductive dielectric material between the first and third plates and between the second and fourth plates having a greater dielectric constant than air.

### Claim 6 (depends on 2)

The rotating machine of claim 2 wherein the first and third capacitor plates are attached to a rotor axle to extend in planes normal to the axis and separated along the axis and wherein the second and fourth are attached to the frame to extend in planes normal to the axis and separated along the axis, and wherein at least two of the first, second, third, and fourth plates may flex axially in response to forces of a fluid captured between the first and second capacitor plates and the third and fourth capacitor plates.

### Claim 7 (depends on 2)

The rotating machine of claim 2 wherein at least two of the first, second, third, and fourth plates include a flexing portion being a portion of the capacitor plates proximate to at least one of the frame or rotor axle.

### Claim 8 (depends on 2)

The rotating machine of claim 2 including a nonconductive dielectric material between the first and third plates and between the second and fourth plates having a greater dielectric constant than air.

### Claim 9 (depends on 2)

The rotating machine of claim 2 further including a solid-state power converter substantially fixed with respect to the frame so as not to rotate with the rotor and communicating with the second and fourth capacitor plates to provide alternating current power to at least one electrical coil synthesized from a DC source.

### Claim 10 (depends on 9)

The rotating machine of claim 9 wherein the power converter provides for regulation of output current to the second and fourth capacitor plates to a predetermined value.

### Claim 11 (depends on 9)

The rotating machine of claim 9 further including an inductance in series with at least one of the capacitor plates wherein the power converter tracks a resonant frequency of a series resonant circuit, including at least the inductance, and a series combination of a capacitance formed between the first and second capacitive plate, and between the third and fourth capacitive plate, and wherein the power converter adjusts the alternating current power to match a frequency of the resonant frequency.

### Claim 12 (depends on 2)

The rotating machine of claim 2 further including a capacitance monitor measuring a capacitance between at least one of the first, second, third, and fourth plates to provide an output signal indicating velocity of the rotor.

### Claim 13 (depends on 2)

The rotating machine of claim 2 further including a rotor speed sensor and a field current control changing an electrical signal providing a magnetic field in the rotating machine as a function of rotor speed from the rotor speed sensor.

### Claim 14 (depends on 2)

The rotating machine of claim 2 further including a capacitance monitor measuring a capacitance between at least one of the first, second, third, and fourth plates to provide an output signal indicating a position of the rotor.

### Claim 15 (depends on 2)

The rotating machine of claim 2 further including a fifth capacitor plate attached to rotate with the rotor and electrically communicating with the rotor and a sixth capacitor plate mounted to a frame so as not to rotate with the rotor and positioned for capacitive coupling with respective first and second capacitor plates wherein the third and fourth capacitor plates are positioned to complete a circuit through the coil and the first and second capacitor plates and the third and fourth capacitor plates when multiphase power is applied to the first, third, and fifth capacitor plates.

### Claim 16 (depends on 1)

The rotating machine of claim 1 further including a power converter substantially fixed with respect to the frame so as not to rotate with the rotor and communicating with the second and fourth capacitor plates to provide alternating current power to at least one electrical coil having a frequency in excess of 50 kHz.

### Claim 17

A method of operating a wound field electrical rotating machine having a rotor mounted for rotation about an axis and including at least one electrical coil having a coil axis with a component perpendicular to the axis, the electrical coil comprising a conductor having first and second conductor ends electrically communicating with a first and second capacitor plate attached to rotate with the rotor, and having a third and fourth capacitor plate mounted to a frame so as not to rotate with the rotor and positioned for capacitive coupling with a respective first and second capacitor plate, the method comprising the step of:
applying an alternating voltage across the third and fourth capacitor plate to induce current flow in the electrical coil to cause continuous rotation of the rotor by capacitive coupling between the first and third and between the second and fourth capacitor plates over a range of angular positions of the rotor about the axis.