CONTROL OF A WIND TURBINE HAVING AN ELECTROLYZER

Abstract

A method of controlling a wind turbine having a generator system coupled to an electrolyzer for producing H2 from water is provided, the method including: identifying a characteristic of a load situation; operating the electrolyzer at a load and/or H2-output above a respective nominal rated value depending on the characteristic of a load situation; monitoring the state of the electrolyzer; and operating the electrolyzer at a load and/or H2-output not above the nominal value, if at least one state parameter is above a threshold.

Claims

1. A method of controlling a wind turbine having a generator system coupled to an electrolyzer for producing H2 from water, the method comprising: identifying a characteristic of a load situation; operating the electrolyzer at a load and/or H2-output above a respective nominal rated value depending on the characteristic of a load situation; monitoring the state of the electrolyzer; and operating the electrolyzer at a load and/or H2-output not above the nominal value, if at least one state parameter is above a threshold, wherein by operating the electrolyzer at a load and/or H2-output above the nominal value, at least one structural mechanical loading of a wind turbine component is reduced.

2. The method according to the claim 1, wherein the load situation comprises an environmental overload situation.

3. The method according to claim 1, further comprising: determining, based on the characteristic of the load situation and/or at least one wind turbine operational parameter, whether operating the electrolyzer at a load and/or H2-output above a respective nominal rated value would cause at least one structural mechanical loading of a wind turbine component to be reduced.

4. The method according to claim 1, the characteristic of the load situation comprises a value of at least one of: a wind speed; a wind turbulence; a wind gust; a thrust; and a temperature.

5. The method according to claim 1, wherein operating the electrolyzer at a load and/or H2-output above a nominal rated value comprises at least one of: supplying power and/or current and/or water to the electrolyzer above a respective nominal or rated value; and operating the electrolyzer at a pressure and/or temperature above a respective nominal or rated value.

6. The method according claim 1, further comprising: increasing power output of the generator system above nominal rated value, thereby keeping the generator torque substantially constant, wherein the generator system comprises a generator coupled to an AC-DC converter.

7. The method according to claim 1, wherein by operating the electrolyzer at a load and/or H2-output above the nominal value, the rotor speed is substantially kept constant and/or the rotor acceleration is limited.

8. The method according to claim 1, wherein monitoring the state of the electrolyzer comprises measuring at least one state parameter comprising at least one of: a temperature; a pressure; a water supply and/or throughput; and a state of at least one electrode.

9. The method according to claim 1, comprising, after identifying a characteristic of the load situation: supplying a portion of increased power output by the generator system to thereby enabling to restrict the load excess above the nominal rated value, the electrolyzer is subjected to.

10. An arrangement of controlling a wind turbine having a generator system coupled to an electrolyzer for producing H2 from water, the arrangement comprising: a load identification module configured to identify a characteristic of a load situation; a control module configured to operate the electrolyzer at a load and/or H2-output above a respective nominal rated value depending on the characteristic of a load situation; a monitoring module configured to monitor the state of the electrolyzer; and wherein the control module is further configured to operate the electrolyzer at a load and/or H2-output not above the nominal value, if at least one state parameter is above a threshold, wherein by operating the electrolyzer at a load and/or H2-output above the nominal value, at least one structural mechanical loading of a wind turbine component is reduced.

11. A wind turbine, comprising: a generator system coupled to an electrolyzer for producing H2 from water; and an arrangement according to claim 10.

12. The method according to claim 1, wherein the wind turbine component is a drive train and/or bearing and/or rotor blade and/or tower.

13. The method according to claim 2, wherein the environmental overload situation is a wind gust and/or a wind turbulence.

14. The method according to claim 9, wherein the local energy storage is an accumulator and/or battery.

15. The method according to claim 10, wherein the wind turbine component is a drive train and/or bearing and/or rotor blade and/or tower.

Description

BRIEF DESCRIPTION

[0034] Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:

[0035] FIG. 1 illustrates a graph for explaining an embodiment of a method for controlling a wind turbine according to an embodiment of the present invention; and

[0036] FIG. 2 schematically illustrates a wind turbine according to an embodiment of the present invention including an arrangement of controlling a wind turbine according to an embodiment of the present invention.

DETAILED DESCRIPTION

[0037] The wind turbine 1 schematically illustrated in FIG. 2 comprises a generator system 2 and an electrolyzer 3 which is coupled to the generator system 2. Thereby, the generator system 2 comprises a generator 8 which is mechanically coupled to a rotation shaft 9 at which plural rotor blades 11 are connected. The wind turbine 1 may be an islanded wind turbine normally not connected to any utility grid.

[0038] Furthermore, the wind turbine 1 comprises an arrangement 10 for controlling the wind turbine 1 according to an embodiment of the present invention. The arrangement comprises a not in detail illustrated load identification module which is adapted to identify a characteristic of a load situation. In particular, the arrangement 10 may therefore receive wind condition measurement data (or load characteristic) 30 from a wind measurement module or system 4. The arrangement 10 further comprises a not in detail illustrated control module which is adapted to operate the electrolyzer 3 at a load and/or H2-output above a respective nominal rated value depending on the characteristic of the identified load situation. Thereby, the arrangement 10 is configured to provide control signals 5 to the electrolyzer 3 and/or to provide control signals 6 to a converter 7 comprised in the generator system 2.

[0039] The arrangement 10 further comprises a not in detail illustrated monitoring module adapted to monitor the state of the electrolyzer 3. For this purpose, the arrangement receives measurement signals 12 generated by one or more measurement sensors arranged close to or within the electrolyzer 3. The sensor measurement signals 12 may for example relate to a pressure and/or temperature and/or water throughput and/or actual power supply to the electrolyzer 3.

[0040] As can be seen in FIG. 2, the generator 8 generates AC power, in particular three-phase AC power 13a, 13b, 13c, and provides the AC power to the converter 7. The converter 7 is an AC-DC converter which generates from the supplied AC power an DC output power 14a, 14b at two DC terminals. The electrolyzer 3 receives the DC power 14a, 14b from the converter 7.

[0041] The embodiment illustrated in FIG. 2 further comprises a local energy storage 15, such as an accumulator and/or battery which connectable via switches 16 to the output terminals of the converter 7. Thereby, the power output by the converter 7 or at least a portion 23a,b of the power output by the converter 7 may be supplied to the local energy storage 15, another portion 22a,b may be supplied to the electrolyzer 3.

[0042] Via an input pipe 17, the electrolyzer 3 is supplied with input water 18. The arrangement 10 can also be adapted to change the flow rate of the input supply water 18 by not illustrated pumps and/or valves. Thus, the control signals 5 may also comprise control signals for one or more valves or pumps in order to adjust the flow rate of the supply input water 18.

[0043] FIG. 1 illustrates in a coordinate system having an abscissa 20 indicating time and having an ordinate 21 indicating power supply (e.g., 22a, 22b illustrated in FIG. 1) to the electrolyzer 3 according to a first curve 23 and according to a second curve 24 which may be derived according to embodiments of the present invention. Reference sign 25 labels a nominal or rated value of the power to be supplied to the electrolyzer 3.

[0044] In a time interval 26, the supply power to the electrolyzer 3 (i.e., according to curve 23) is below the rated or nominal threshold value 25. In a second time interval 27, a load situation occurs, where for example the wind turbulence increases and/or a gust occurs. According to a conventional control method, the supply power to the electrolyzer 3 is regulated according to the curve 23 which follows the threshold 25 of the supply power.

[0045] According to embodiments of the present invention, however, the supply power to the electrolyzer 3 may be according to the curve 24. The curve 24 is characterized in that the supply power is above the supply power threshold 25. Thereby, the electrolyzer is operated at a load above a respective nominal rated value, for example the rated or nominal or threshold value 25.

[0046] Alternatively, or additionally to supplying the supply power 22a, 22b to the electrolyzer 3 above the respective rated or nominal value (e.g., according to curve 24), also the water supply 18 may be enhanced relative to a respective other nominal value or rated value.

[0047] In a third time interval 28, the increased turbulence or increased gust reduces such that the electrolyzer is supplied with supply power 28a, 28b below the rated or nominal value 25. In another embodiment, in the third time interval 28, the temperature of the electrolyzer is above a threshold, and the electrolyzer is supplied with supply power 28a, 28b below the rated or nominal value 25. In a fourth time interval 29, turbulence and/or gust increases again and the electrolyzer is again operated at a load above the respective nominal or rated value 25 of the supply power. Thereby, in the two-time intervals 27 and 29, more H2 can be generated compared to the conventionally performed method.

[0048] The arrangement 10 is adapted to carry out a method of controlling a wind turbine according to an embodiment of the present invention. While the electrolyzer 3 is operated at a load and/or H2-output above a respective nominal rated value, the electrolyzer 3 is being monitored, involving reception of sensor measurement signals 12 of the arrangement 10. Thereby, the arrangement 10 would adjust the operation condition of the electrolyzer 3, if at least one state parameter of the electrolyzer 3 is above a threshold or if any evaluation logic demands to adjust the operation of the electrolyzer 3. If for example an evaluation logic considering one or more of the measurement values 12 determines, that the operation of the electrolyzer (above rated load) should be stopped or at least diminished, the arrangement 10 may provide control signals 5 to the electrolyzer and/or control signals 6 to the converter 7 in order to appropriately adjust the operation of the electrolyzer. Other wind turbine operating parameters may be changed as well.

[0049] Components of the wind turbine which may thereupon experience less load compared to the situation in which the electrolyzer is not operated at an overload, the components may for example include drive train components including a bearing, a gearbox which is optional, tower construction, rotor blades, etc. The wind measurement system 4 may for example be configured to measure wind speed, wind turbulence, wind gust, thrust, temperature, etc.

[0050] Embodiments of the present invention may for example be applied during a load situation where a gust occurs. At the onset of a gust, then the power extracted from the rotor may be increased significantly above the nominal/load term power target and thereby keep the rotor from accelerating or accelerate the rotor to a lower degree compared to a conventional method. This may reduce the structural loading of the wind turbine during gust events. The electrolyzer may have a rated/nominal current which may temporarily be increased during the gust. Similar, the electrolyzer may have a rated/maximum temperature that may be temporarily increase during gust events.

[0051] Embodiments of the present invention may also be applied in a load situation including wind turbulence or increased wind turbulence. The wind turbulence may result in the possible power production to vary. When there is a dip in wind speed, the power production may decrease and vice versa. Embodiments of the present invention contemplate the turbine operating just below rated wind speed. When the wind speed dips, power is lost, but when the wind speed increases, maximum power is soon reached, and less power is gained compared to the power lost during dips. This would cause the mean to decrease. When, however, according to an embodiment of the present invention, the external power limitation is removed, the wind turbine may be free to produce as much H2 as possible with the available power from the wind. Thereby, the power curve 23 may reflect the power or H2 used with external factors imposing a maximum limit, as for example employed in a conventional system. The curve 24 indicates power output or H2-output as obtained according to embodiments of the present invention, which can be produced with the limits removed. The result is more power or more hydrogen being produced.

[0052] Removing the external factors limiting peak power and/or H2 production may increase the peak power extractor from the rotor. It may be used to limit the rotor speed during gusts thereby to reduce structural load on one or more wind turbine components. It may also be used to increase the H2 production during operation and turbulent wind but not limiting the short-term power.

[0053] Alternatively, or additionally, the inverter or converter may be overdesigned and then a local storage (for example local storage 15 illustrated in FIG. 2 such as a supercapacitor) may be supplied with access supply power. Thereby, the output power may be smoothened and enabling the electrolyzer to be operated at a lower rating.

[0054] Although the present invention has been disclosed in the form of embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of the invention.

[0055] For the sake of clarity, it is to be understood that the use of a or an throughout this application does not exclude a plurality, and comprising does not exclude other steps or elements.