Method for examining an electric energy accumulator

1. A method for checking an electric energy storage device for a blade angle adjustment drive of a wind turbine, wherein the blade angle adjustment drive includes an electric motor having a motor shaft for adjusting an angle of a blade of the wind turbine, the method comprising:

using a control unit to generate an electrical signal to controllably move a braking component into frictional contact with a brake disc operably associated with the motor shaft of the electric motor to provide a braking action on the motor shaft, and thereby preventing rotation of the blade of the wind turbine;

loading an electric energy storage device using the electric motor with a converter, while rotation of the motor shaft of the electric motor is being physically prevented by frictional contact of the braking component with the motor shaft;

observing a discharging of the electric energy storage device while rotation of the motor shaft is being physically prevented; and

detecting a time course during which the discharging is taking place to produce time course data for an electrical signal relating to the discharging of the electric storage energy device, wherein the electrical signal relates to at least one of an intermediate circuit voltage associated with the converter or a current being drawn by the motor from an output stage of the converter, while the braking component is frictionally engaged with the motor shaft to simulate a load.

2. The method according to claim 1 , further comprising observing the discharging of the electric energy storage device with the control unit, wherein the control unit is integrated in the converter, which said control unit activates the output stage of the converter to control a current of the electric motor.

3. The method according to claim 1 , further comprising electrically connecting the electric energy storage device to the intermediate circuit of the converter during loading.

4. The method according to claim 3 , further comprising electrically separating the intermediate circuit at a time before or at the loading of the electric energy storage device from a primary power supply and wherein the intermediate circuit is electrically separated during loading from the primary power supply.

5. The method according to claim 1 , further comprising controlling a current of the electric motor during the loading of the electric energy storage device by the converter.

6. The method according to claim 1 , further comprising determining a storable charging quantity of at least one of the electric energy storage device and a charging state of the electric energy storage device based on observing the discharging of the electric energy storage device.

7. The method according to claim 1 , wherein the electric energy storage device comprises at least one accumulator.

8. The method according to claim 1 , wherein the electric energy storage device comprises at least one capacitor.

9. The method according to claim 8 , further comprising determining an electrical capacitance of the capacitor based on observing the discharging of the electric energy storage device.

10. The method according to claim 1 , further comprising deactivating the braking component from contact with the motor shaft of the electric motor after the discharging of the electric energy storage device has been observed.

11. A blade angle adjustment drive for a wind turbine comprising:

a converter having a direct voltage intermediate circuit adapted to be electrically fed by a primary power supply;

an electric motor which is electrically coupled to the converter and adapted to be supplied with electric energy by the converter; and

an electric energy storage device, by which the electric motor is supplied with electric energy using the intermediate circuit when the primary power supply fails;

a braking component adapted to be moved into physical engagement with a motor shaft of the electric motor to provide a braking action on the motor shaft, to thus enable the electric motor to be used as a load component, while the motor shaft is physically braked by the braking component, during testing of the energy storage device;

wherein the intermediate circuit is adapted to be electrically separated from the primary power supply without preventing further use of the converter with the electric energy storage device;

when the primary power supply is separated from the intermediate circuit, the electric energy storage device is adapted to be electrically loaded by the converter and the electric motor as a result of the motor shaft being braked by the braking component;

a discharging of the electric energy storage device, while being loaded by the electric motor as the motor shaft of the electric motor is being braked, is adapted to be observed; and

a time course during which the discharging is occurring is determined to produce time course data for an electrical signal pertaining to the discharging of the electric energy storage device while the braking component is physically engaged with the motor shaft to simulate a load; and

wherein the electrical signal comprises at least one of an intermediate circuit voltage associated with the converter or a current being output from an output stage of the converter.

12. The blade angle adjustment drive according to claim 11 , further comprising a control unit for observing the discharging of the electric energy storage device, wherein the control unit is integrated in the converter and is operable to activate the output stage of the converter to control a motor current flowing through the electric motor while the motor shaft of the electric motor is being braked by the braking component.

13. The blade angle adjustment drive according to claim 11 , wherein the electric energy storage device is adapted to be electrically connected to the intermediate circuit.

14. The blade angle adjustment drive according claim 11 , further comprising:

a control unit operable to actuate the braking component; and

the primary power supply adapted to be electrically decoupled from the intermediate circuit while the discharging of the electric energy storage device is occurring as a result of the electric motor being loaded by engagement of the braking component with the motor shaft, to thus enable discharging of the electric energy storage device to be observed.

15. A blade angle adjustment drive for a wind turbine comprising:

a control unit;

a converter having a direct voltage intermediate circuit adapted to be electrically fed by a primary power supply;

an electric motor which is electrically coupled to the converter and adapted to be supplied with electric energy by the converter;

an electric energy storage device configured to be switched, in response to a signal from the control unit, to supply the electric motor with electric energy, using the intermediate circuit, when the primary power supply fails;

a braking component, controlled by an additional signal from the control unit, to physically engage a motor shaft of the motor to apply a braking action to the motor shaft of the electric motor while discharging of the electric energy storage device is being observed, to thus enable the electric motor to be used as a load component during the discharging of the electric energy storage device;

wherein the control unit further obtains time course data for an electrical signal pertaining to the electrical energy storage device during the discharging, and while the braking component is physically braking the motor shaft, to simulate a load; and

wherein the electrical signal includes at least one of an intermediate circuit voltage associated with the converter or a current being output by an output stage of the converter.

16. The blade angle adjustment drive according to claim 15 , wherein the intermediate circuit is adapted to be electrically separated from the primary power supply by the control unit when testing of the electric energy storage device is being performed.