ELECTROMAGNETIC BRAKING SYSTEMS AND METHODS

• US 20140001756A1
• Filed: 06/28/2012
• Published: 01/02/2014
• Est. Priority Date: 06/28/2012
• Status: Active Grant

• Current Assignee: Ai Alpine Us Bidco LLC
• Original Assignee: General Electric Company
• Inventors: Panosyan, Ara, Schramm, Simon Herbert, Hemmelmann, Jan Erich, Sihler, Christof Martin, Papini, Francesco, Dong, Xiaoting, Huber, Johannes
• Granted Patent: US 9,413,217 B2
• Time in Patent Office: Days
• US Class Current: 290/7
• CPC Class Codes: F03D 7/0244 for braking
• CPC Class Codes: F03D 7/0272 by measures acting on the electrical generator
• CPC Class Codes: F16D 2121/20 using electromagnets
• CPC Class Codes: H02K 49/046 with an axial airgap
• CPC Class Codes: H02P 3/04 Means for stopping or slowing by a separate brake, e.g. friction brake, eddy-current brake brakes F16D, H02K49/00
• CPC Class Codes: H02P 9/06 Control effected upon clutch or other mechanical power transmission means and dependent upon electric output value of the generator
• CPC Class Codes: Y02E 10/72 Wind turbines with rotation axis in wind direction

Abstract

An electromagnetic braking system of a power generation system includes an electrically conductive disc coupled to a rotatable shaft operatively coupled between a prime mover and a generator; a controller for receiving a status signal from the power generation system and for generating a control signal based on the status signal; and an inducting unit for applying an electromagnetic braking force on the electrically conductive disc when commanded by the control signal to regulate a rotational speed of the rotatable shaft.

Claims

1. An electromagnetic braking system comprising:

an electrically conductive disc coupled to a rotatable shaft of a power generation system, wherein the rotatable shaft is operatively coupled between a prime mover and a generator;

a controller for receiving at least one status signal from the power generation system and for generating a control signal based on the at least one status signal;

an inducting unit for applying an electromagnetic braking force on the electrically conductive disc when commanded by the control signal to regulate a rotational speed of the rotatable shaft.

2. The electromagnetic braking system of claim 1, wherein the inducting unit comprises:

a plurality of inductors;

a power source for supplying at least one of an alternating current and a direct current to the inductors to induce eddy currents in the electrically conductive disc; and

an electrical switch coupled between the inductors and the power source for regulating the at least one of the alternating current and the direct current as commanded by the control signal.

3. The electromagnetic braking system of claim 2, wherein the inductors are disposed proximate to the electrically conductive disc to create a first magnetic field across the electrically conductive disc, wherein the created first magnetic field induces the eddy currents in the electrically conductive disc when the electrically conductive disc rotates through the first magnetic field.

4. The electromagnetic braking system of claim 3, wherein the induced eddy currents in the electrically conductive disc create a second magnetic field opposing the first magnetic field to resist rotation of the electrically conductive disc.

5. The electromagnetic braking system of claim 1, wherein the at least one status signal is representative of the rotational speed of the rotatable shaft, a voltage in the power grid, a current at the generator, a mechanical power produced by the prime mover, a rotor angle of the generator, an electrical power produced by the generator or combinations thereof.

6. The electromagnetic braking system of claim 5, wherein the controller is configured to cause the control signal to initiate and regulate the electromagnetic braking force when the voltage in the power grid is a fault voltage.

7. The electromagnetic braking system of claim 5, wherein the controller is configured to cause the control signal to initiate and regulate the electromagnetic braking force when at least one of the rotational speed of the rotatable shaft is above a threshold speed and the rotor angle of the generator is above a threshold angle.

8. The electromagnetic braking system of claim 5, wherein the controller is configured to cause the control signal to apply the electromagnetic braking force when the mechanical power produced by the prime mover is above a first threshold power or the electrical power produced by the generator is below a second threshold power.

9. The electromagnetic braking system of claim 5, wherein the controller is configured to cause the control signal to initiate and regulate the electromagnetic braking force when the current at the generator is above a threshold current.

10. The electromagnetic braking system of claim 5, wherein the controller is configured to cause the control signal to stop or regulate the power produced by the prime mover based on the received status signal.

11. A method comprising:

receiving at least one status signal representative of a rotational speed of a rotatable shaft, a voltage in the power grid, a current at the power generator, a mechanical power produced by a prime mover, a rotor angle of the power generator, an electrical power produced by the power generator or combinations thereof;

determining a control signal based on the at least one status signal; and

applying an electromagnetic braking force on the rotatable shaft when commanded by the control signal to regulate the rotational speed of the rotatable shaft.

12. The method of claim 11, wherein applying the electromagnetic braking force on the rotatable shaft comprises:

creating a first magnetic field across an electrically conductive disc coupled to the rotatable shaft;

inducing eddy currents in the electrically conductive disc when the electrically conductive disc rotates through the first magnetic field; and

using the induced eddy currents in the electrically conductive disc for creating a second magnetic field opposing the first magnetic field to resist rotation of the electrically conductive disc.

13. The method of claim 12, wherein creating the first magnetic field around the electrically conductive disc comprises sending at least one of an alternating current and a direct current to a plurality of inductors, wherein the at least one of the alternating current and the direct current is corresponding to the control signal.

14. The method of claim 13, further comprising:

determining whether at least one of the rotational speed of the rotatable shaft is above a threshold speed and the rotor angle of the generator is above a threshold angle;

if so, sending the control signal to the inducting unit for applying the electromagnetic braking force on the rotatable shaft to maintain synchronism between the generator and the power grid.

15. The method of claim 13, further comprising:

determining whether the voltage in the power grid is a fault voltage;

if so, sending the control signal to the inducting unit for applying the electromagnetic braking force on the rotatable shaft.

16. The method of claim 13, further comprising:

determining whether the mechanical power produced by the prime mover is above a first threshold power or the electrical power produced by the power generator is below a second threshold power;

if so, sending the control signal to the inducting unit for applying the electromagnetic braking force on the rotatable shaft.

17. The method of claim 13, further comprising:

determining whether the current at the generator is above a threshold current;

if so, sending the control signal to the inducting unit for applying the electromagnetic braking force on the rotatable shaft.

18. The method of claim 11, further comprising:

determining whether the mechanical power produced by the prime mover is above a first threshold power or the electrical power produced by the power generator is below a second threshold power;

if so, sending the control signal to regulate the generation of the mechanical power for a pre-determined time period.

19. A power generation system comprising:

a prime mover for creating mechanical power;

a generator operatively coupled to the prime mover through a rotatable shaft for generating electrical current based on the mechanical power and supplying the electrical current to a power grid; and

an electromagnetic braking unit operatively coupled to the rotatable shaft for regulating a rotational speed of the rotatable shaft.

20. The power generation system of claim 19, wherein the electromagnetic braking unit comprises:

an electrically conductive disc coupled to the rotatable shaft; and

a controller for performing the steps of;

receiving at least one signal representative of the rotational speed of the rotatable shaft, a voltage in the power grid, a current at the generator, a mechanical power produced by the prime mover, a rotor angle of the generator, an electrical power produced by the generator or combinations thereof; and

determining a control signal based on the at least one signal, wherein the control signal is representative of the fault conditions in the power generation system; and

an inducting unit for applying an electromagnetic braking force on the electrically conductive disc based on the determined control signal.