Method for charging an electric emergency energy storage device

1. A method for charging a supercapacitor of an electric emergency energy storage device of a pitch drive of a wind turbine, comprising the following steps:

predicting an energy demand E B of the pitch drive;

determining a capacitance C of the supercapacitor and an internal resistance R i of the supercapacitor;

calculating a charging voltage U L , wherein the charging voltage U L is calculated in such a way that an energy loss E V , being an amount of energy loss due to the determined internal resistance R i , combined with a partial energy E T , being an amount of energy that corresponds to the difference between the energy E C stored in the supercapacitor at the charging voltage U L and the energy stored in the supercapacitor at a lower limit voltage U G , is substantially equal to the predicted energy demand E B ; and

charging or discharging the supercapacitor until the calculated charging voltage U L has been reached.

2. The method for charging an electric emergency energy storage device according to claim 1 , wherein the predicted energy demand E B is expressed as a load current curve l(t) and a load resistance R L , or as a load current curve l(t) and a load voltage curve Û(t), or as a load resistance R L and a load voltage curve Û(t).

3. The method for charging an electric emergency energy storage device according to claim 2 , wherein the energy E C stored in the supercapacitor at the charging voltage U L is assumed to be the sum of the losses due to the internal resistance R i of the supercapacitor at the load current curve l(t) prescribed by the predicted energy demand E B plus the electric energy supplied by the supercapacitor at the load current curve l(t).

4. The method for charging an electric emergency energy storage device according to claim 1 , wherein a safety correction function is added to the predicted energy demand E B and/or the predicted energy demand E B is multiplied by a safety correction function.

5. The method for charging an electric emergency energy storage device according to claim 1 , wherein the calculated charging voltage U L is increased by a constant value and/or multiplied by a safety factor.

6. The method for charging an electric emergency energy storage device according to claim 1 , wherein a load measurement is carried out and the predicted energy demand E B is at least partially based on the results of the load measurement.

7. The method for charging an electric emergency energy storage device according to claim 1 , wherein a status signal is emitted as a function of the calculated charging voltage U L , and/or of the predicted energy demand E B , and/or of the determined capacitance C, and/or of the determined internal resistance R i .

8. The method for charging an electric emergency energy storage device according to claim 7 , wherein a first status signal is emitted when the calculated charging voltage U L is not greater than a first limit value.

9. The method for charging an electric emergency energy storage device according to claim 8 , wherein a second status signal is emitted when the calculated charging voltage U L is greater than the first limit value and not greater than a second limit value.

10. The method for charging an electric emergency energy storage device according to claim 9 , wherein a third status signal is emitted when the calculated charging voltage U L is greater than the second limit value and not greater than a third limit value.

11. The method for charging an electric emergency energy storage device according to claim 10 , wherein a fourth status signal is emitted when the calculated charging voltage U L is greater than the third limit value and the third limit value is a maximum permissible charging voltage U L, max .

12. The method for charging an electric emergency energy storage device according to claim 11 , wherein, if the calculated charging voltage U L is greater than the maximum permissible charging voltage U L, max , the calculated charging voltage U L is reduced to the maximum permissible charging voltage U L, max .

13. A non-transitory computer readable storage medium with program instructions for carrying out a method according to claim 1 .