# US 8,541,897 B2 · Generation of electric energy using cable-supported windmills

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 8,541,897 B2
- Document ID: US8541897B2
- Status: Granted
- Kind: B2
- Application number: 12/873,534
- Filed: 2010-09-01
- Published: 2011-03-03
- Granted: 2013-09-24
- Earliest claimed: 2009-09-01
- Assignees: University of Southern California
- Applicants: Behrokh Khoshnevis
- Inventors: Behrokh Khoshnevis
- Web page: https://patentgrep.com/patent/US8541897B2

## CPC

- F03D 3/02: having a plurality of rotors
- F03D 9/255: {connected to electrical distribution networks; Arrangements therefor}
- F03D 9/28: the apparatus being a pump or a compressor
- F03D 13/20: Arrangements for mounting or supporting wind motors; Masts or towers for wind motors
- F03D 15/10: using gearing not limited to rotary motion, e.g. with oscillating or reciprocating members
- F05B 2240/213: of the Savonius type
- F05B 2240/40: Use of a multiplicity of similar components
- F05B 2240/911: already existing for a prior purpose
- F05B 2240/917: attached to cables
- F05B 2250/25: helical
- F05B 2260/4031: as in toothed gearing
- F05B 2260/406: through hydraulic systems
- Y02E 10/728: Onshore wind turbines
- Y02E 10/74: Wind turbines with rotation axis perpendicular to the wind direction
- F03D: WIND MOTORS
- F05B: INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

An electric energy generation system may include a plurality of windmills, a windmill support system, an electric generator, and a coupling system. The windmills may each be configured to transform wind energy into rotational energy. The windmill support system may support the windmills in positions that are spaced apart from one another. The electric generator may be configured to transform rotational energy into electric energy. The coupling system may be configured to couple the rotational energy generated by each of the windmills to the electric generator in a manner that permits the windmills to rotate at different speeds during operation of the electric energy generation system. Other configurations are also disclosed.

## Claims

### Claim 1

An electric energy generation system comprising:
a plurality of windmills, each configured to transform wind energy into rotational energy;
a windmill support system supporting the plurality of windmills in positions that are spaced apart from one another;
an electric generator configured to transform rotational energy into electric energy; and
a coupling system, including a common shaft configured to be driven by each of the plurality of windmills, comprising:
a flexible coupling between each neighboring set of windmills configured to permit the common shaft to bend along its shaft axis during operation of the electric energy generation system, or
a telescoping coupling between each neighboring set of windmills configured to permit the length of the common shaft between each neighboring set of windmills to change during operation of the electric energy generation system,
wherein the coupling system is configured to couple the rotational energy generated by each of the plurality of windmills to the electric generator in a manner that permits the plurality of windmills to rotate at different speeds during operation of the electric energy generation system.

### Claim 2 (depends on 1)

The electric energy generation system of claim 1 wherein the coupling system includes:
a common shaft configured to be driven by each of the plurality of windmills; and
for each of the plurality of windmills, a ratchet gear coupling the windmill to the common shaft.

### Claim 3 (depends on 1)

The electric energy generation system of claim 1 wherein the coupling system includes:
a common shaft coupled to each of the plurality of windmills; and
for each of the plurality of windmills, an automatic transmission connected between the windmill and the common shaft.

### Claim 4 (depends on 1)

The electric energy generation system of claim 1 wherein the electric generator is on the ground.

### Claim 5 (depends on 1)

The electric energy generation system of claim 1 wherein the windmill support system includes at least one cable supporting the windmills.

### Claim 6 (depends on 5)

The electric energy generation system of claim 5 wherein:
the coupling system includes a common shaft coupled to each of the plurality of windmills; and
the common shaft includes a flexible coupling between each neighboring set of windmills configured to permit the common shaft to bend along its shaft axis during operation of the electric energy generation system.

### Claim 7 (depends on 5)

The electric energy generation system of claim 5 wherein:
the coupling system includes a common shaft coupled to each of the plurality of windmills; and
the common shaft includes a telescoping coupling between each neighboring set of windmills configured to permit the length of the common shaft between each neighboring set of windmills to change during operation of the electric energy generation system.

### Claim 8 (depends on 1)

The electric energy generation system of claim 1 wherein:
the windmill support system includes:
two cables spaced apart from one another; and
a windmill support coupled to the two cables and to the windmills;
and further comprising:
a counterbalancing system configured to substantially counterbalance rotational torque applied by the windmills to the windmill support during operation of the electric energy generation system.

### Claim 9 (depends on 8)

The electric energy generation system of claim 8 wherein the counterbalancing system includes at least one flap configured to convert wind energy into counterbalancing rotational force that is applied to the windmill support during operation of the electrical energy generation system.

### Claim 10 (depends on 8)

The electric energy generation system of claim 8 further comprising an arm connected between the flap and the windmill support.

### Claim 11 (depends on 8)

The electric energy generation system of claim 8 wherein:
one of the windmills is a first windmill; and
the counterbalancing system includes a second of the windmills configured to rotate in a direction opposite the rotational direction of the first windmill during operation of the electric energy generating system.

### Claim 12 (depends on 11)

The electric energy generation system of claim 11 wherein the counterbalancing system includes an arm coupled to the windmill support and to and between each of the windmills.

### Claim 13 (depends on 12)

The electric energy generation system of claim 12 wherein the first and the second windmills both face in the same direction.

### Claim 14 (depends on 1)

The electric energy generation system of claim 1 further comprising:
an energy transfer system configured to transfer the rotational energy generated by each of the plurality of windmills to the electric generator, the energy transfer system including:
for each of the windmills, a hydraulic pump coupled to the windmill and configured to transform the rotational energy of the windmill into fluidic pressure; and
a hydraulic motor coupled to the electric generator and configured to transform the fluidic pressure from the hydraulic pumps into rotational energy.

### Claim 15 (depends on 14)

The electric energy generation system of claim 14 wherein the energy transfer system includes, for each of the hydraulic pumps, a check valve configured to prevent fluid from flowing through the hydraulic pump in the reverse direction.

### Claim 16 (depends on 14)

The electric energy generation system of claim 14 wherein each of the hydraulic pumps are configured to provide a substantially constant output pressure, not withstanding changes in the rotational rate of the windmill to which the hydraulic pump is coupled.

### Claim 17

An electric energy generation system comprising:
a windmill support system which includes a lattice of substantially vertical supports that lie in substantially different planes and at least one substantially horizontal cable connecting each vertical support to each of its immediately neighboring vertical supports;
at least one windmill suspended from each of the substantially horizontal cables; and
one or more electric generators configured to transform the rotational energy from the plurality of windmills into electric energy.