Wind turbine and method for controlling a wind turbine

Abstract

A wind turbine with a tower and a nacelle with a nacelle housing is provided. The nacelle is placed on the tower. Further provided is a cooling flap, which is configured to close an opening in or on the area of the wind turbine to be cooled. At least one temperature-dependent passive actuator is configured to activate and open the cooling flap as a function of temperature, so as to enable a heat compensation in the area to be cooled by means of the opening. The temperature-dependent passive actuator can change its shape and/or its length without any external electrical energy as a function of temperature.

Claims

1. A wind turbine, comprising: a tower; a nacelle with a nacelle housing, which is placed on the tower; at least one cooling flap, which is configured to close an opening in or on an area of the wind turbine to be cooled; and at least one temperature-dependent passive actuator, which is coupled to the cooling flap and is configured to activate and open the cooling flap as a function of temperature, so as to enable a heat compensation in the area to be cooled by means of the opening, wherein the at least one temperature-dependent passive actuator is configured to change its length without external electrical energy as a function of the temperature to open or close the at least one cooling flap, wherein the wind turbine has a normal operating mode, and an error operating mode, in which the wind turbine is not connected to an energy supply network and/or not enough energy is being supplied for active cooling, and in which a temperature exceeds a limit value in the area of the wind turbine, and wherein the at least one temperature-dependent passive actuator is configured to open the at least one cooling flap as a function of temperature in the error operating mode, so as to enable the heat compensation in the area of the wind turbine.

2. The wind turbine according to claim 1, wherein the area of the wind turbine is configured as the nacelle housing with at least one opening, which can be closed by means of the at least one cooling flap.

3. The wind turbine according to claim 1, wherein: the nacelle housing has at least one heat source in the form of an electric generator and/or a power electronics unit, wherein at least one power electronics unit generates a quantity of heat that exceeds a threshold value in an error operating mode, and wherein the at least one passive temperature-dependent passive actuator is configured to open the at least one cooling flap as a function of the heat generated by the power electronics unit.

4. The wind turbine according to claim 1, wherein: the passive temperature-dependent actuator is configured as a bimetal actuator, as an oil cylinder with a temperature-dependent expansion, or as a melting cylinder with a temperature-dependent expansion.

5. The wind turbine according to claim 1, wherein: the at least one passive temperature-dependent passive actuator has a surface enlargement on its surface to improve a heat exchange.

6. The wind turbine according to claim 1, further comprising: a heat pipe between a heat source and the at least one passive temperature-dependent passive actuator.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) Advantages and exemplary embodiments will be described in more detail below with reference to the drawings.

(2) FIG. 1 shows a schematic view of a wind turbine.

(3) FIG. 2 shows a schematic view of a nacelle of a wind turbine.

(4) FIG. 3A shows a graph to illustrate the expansion of different passive actuators via the temperature.

(5) FIG. 3B shows different passive temperature-dependent actuators.

(6) FIGS. 4A to 4E each show a cutout of a nacelle of a wind turbine with different passive temperature-dependent actuators.

(7) FIG. 5 shows a graph to illustrate a time dependence of an air temperature in the nacelle for different cooling configurations.

DETAILED DESCRIPTION

(8) FIG. 1 shows a schematic view of a wind turbine. The wind turbine 100 has a tower 102 with a nacelle 200 on the tower. The wind turbine has an aerodynamic rotor 106 with a spinner 110 and three rotor blades 108. The nacelle 200 has a nacelle housing 210. The wind turbine 100 has an electric generator 300, which is directly or indirectly coupled with the aerodynamic rotor 106. During rotation of the aerodynamic rotor 106, the rotor of the generator 300 is set in motion, so that the generator generates electrical energy.

(9) FIG. 2 shows a schematic view of a nacelle of a wind turbine. The nacelle 200 has a nacelle housing 210 and at least one opening 211, which can be closed by a cooling flap 220. An electric generator 300 is directly or indirectly coupled with an aerodynamic rotor 106, wherein the rotor has rotor blades 108. The electric generator 300 is coupled with several power electronic units 410, 420, 430. These three power electronic units 410, 420, 430 are arranged inside of the nacelle housing 210. For example, the power electronic units 410, 420, 430 can consist of a rectifier 410, a DC link 420 and a chopper 430. Alternatively thereto, additional power electronic units 210 can also be arranged in the nacelle housing. For example, this type of power electronic unit can be an inverter. During operation of the wind turbine, the generator 300 and the power electronic units can generate heat, i.e., they are heat sources. The nacelle can thus represent an area to be cooled 200.

(10) The wind turbine 100 can have a normal operating mode and at least one error operating mode.

(11) During wind turbine operation, the aerodynamic rotor 106 rotates, and sets a rotor of the generator 300 in motion. As a result, the electric generator 300 generates electrical energy, which is delivered to the first power electronics unit 410, for example for rectification purposes. After rectification by the rectifier 410, a DC link 420 can be provided. The chopper 430 can be used to convert energy that has been generated by the generator but cannot be delivered to the energy supply network into heat. This can take place in particular in the event of an error, i.e., given a network error. It can here come about that the wind turbine must not deliver any energy to the energy supply network. However, given the inertia of the aerodynamic rotor 106, a situation can arise where the generator continues to generate energy. Since this energy cannot be delivered to the energy supply network, this energy can be converted into heat by the chopper 430 in an error operating mode. During chopper operation, i.e., while the electrical energy generated by the generator is being converted into heat, a significant increase in temperature inside of the nacelle housing 210 inevitably takes place. This temperature increase can have a detrimental impact on the power electronic units or other components inside of the nacelle housing 210. In order to prevent this, at least one temperature-dependent actuator 500 is provided that can open the cooling flap 220 at the opening 211 in the nacelle housing 210.

(12) FIG. 3A shows a graph to illustrate the expansion of different passive actuators via the temperature. FIG. 3B shows different examples of the passive actuators. FIG. 3A shows the temperature-dependent expansion of a melting cylinder 530, a bimetal actuator 510 and an oil cylinder 520. The bimetal actuator 510 as well as the oil cylinder actuator 520 each have a linear correlation between rising temperature and expansion. Only for the melting cylinder actuator 530 is there no linear correlation. Instead, no notable expansion takes place up to a limit value. Only starting with the limit value does an expansion of the cylinder to a second limit value take place as temperature rises. No notable additional expansion takes place above the second limit value, even given a rising temperature.

(13) The passive temperature-dependent actuator 500 is used to open an opening 211 in a nacelle housing 210 as a function of temperature. The actuator 500 can be configured as a bimetal actuator 510. To this end, the bimetal actuator has a first and second metal section 511, 512, which are made out of a different material and have different heat expansion coefficients. During a temperature increase, the first and second metal sections 511. 512 expand differently, which leads to a change in shape, for example a bending or curvature of the bimetal actuator 510.

(14) Alternatively thereto, the passive temperature-dependent actuator can be configured as an actuator with an oil cylinder. The oil cylinder 520 has a cylinder section 521 and a first and second end 523, 524. Provided inside of the cylinder 521 is a heat expanding material, e.g., such as oil 522, which expands as temperature increases, so that a length of the oil cylinder is enlarged given a temperature increase. This is shown on FIG. 3.

(15) The passive temperature-dependent actuator can further be configured as a melting cylinder 530. The melting cylinder 530 has a cylinder 531 and a first and second end 533, 534. Further provided is a melting material 532 in the cylinder 531. As the temperature rises, the material 532 melts until it is in a liquid state (see right image on FIG. 3B). This leads to an expansion of the material 532, and hence to a change in length of the melting cylinder.

(16) The actuator can at least partially have thermal ribs for an improved and faster activation of the temperature-dependent passive actuator. Alternatively thereto, the actuator can be coupled with a heat pipe or a heat pipe, so as to improve how a temperature, for example of the chopper, is relayed to the temperature-dependent passive actuator, so that a reaction can take place quickly, and the cooling flap of the opening is opened.

(17) This also enables a quick reaction to an excessive temperature inside of the nacelle housing, and in particular in the area of the chopper.

(18) FIG. 4A to 4F each show a cutout of a nacelle of a wind turbine. FIG. 4A shows the nacelle housing 210 with a power electronics unit 430, which can have a chopper 430. The nacelle housing 210 according to FIG. 4A can optionally have an opening (not shown) for active cooling. Active cooling can take place when enough energy is available.

(19) FIG. 4B shows a nacelle housing with a power electronics unit and a chopper. The chopper 440 has a chopper housing 441 optionally with at least one opening 442. Provided in the housing 210 is an opening 211, which can be closed by a cooling flap 220. Further provided is a temperature-dependent passive actuator 500, which is coupled with the cooling flap 220, and opens the cooling flap when a corresponding limit temperature is exceeded.

(20) FIG. 4C shows the structure of FIG. 4B, wherein the actuator 510 has a plurality of surface enlargements, e.g., in the form of ribs 510.

(21) FIG. 4D is based on the configuration of the nacelle housing on FIG. 4B, wherein a heat pipe or a heat pipe 550 is provided between the chopper and the passive actuator.

(22) FIG. 4E shows a situation as depicted on FIG. 4B, wherein an additional opening 211 is provided in the nacelle housing 210 with an additional cooling flap 220. As a consequence, several openings with several cooling flaps can be opened by the temperature-dependent passive actuators as a function of temperature.

(23) FIG. 5 shows a graph to illustrate a time dependence of an air temperature in the nacelle for different cooling configurations. Provided in particular is the case without cooling A1 (see FIG. 4A), and a case A2 with openings 211 in the nacelle housing 210, and a cooling flap 200 that can be closed or is to be opened by means of a passive actuator 500 (see FIG. 4B). Further depicted is a ribbed configuration of the actuator A3 as well as a configuration with a heat pipe or a heat pipe (see FIG. 4C).

REFERENCE LIST

(24) 100 Wind turbine 102 Tower 106 Rotor 108 Rotor blades 110 Spinner 200 Nacelle 210 Nacelle housing 211 Opening 220 Cooling flap 300 Generator 410 Power electronic units 420 Power electronic units 430 Power electronic units 440 Chopper 441 Chopper housing 442 Opening 500 Passive actuator 510 Bimetal actuator 511 First metal section 512 Second metal section 520 Oil cylinder 521 Cylinder section 522 Oil 523 First end 524 Second end 530 Melting cylinder 531 Cylinder 532 Melting material 533 First end 534 Second end 550 Heat pipe

(25) European patent application no. 22212206.1, filed Dec. 8, 2022, to which this application claims priority, is hereby incorporated herein by reference, in its entirety.