A method for controlling ice melting of wind turbine blades

Abstract

The present invention relates to the technical field of wind turbine de-icing, and discloses a wind turbine blade de-icing control method, wherein step S101 monitors the temperature of the surface of the wind turbine blade in real time, and constructs a first position temperature sequence according to the time interval v; step S102 calculates the actual temperature of each position on the surface of the wind turbine blade according to the position temperature sequence, and generates a second position temperature sequence. The present invention first corrects the parameters obtained by the temperature sensing device to avoid the mismatch between the obtained temperature and the actual temperature on the surface of the wind turbine. Secondly, when de-icing the ice layer, the possible weight difference between the three blades is taken into account, and the synchronous de-icing operation is performed after the weight difference is smoothed. Compared with the general de-icing method, the de-icing can be achieved without stopping the machine, and the wind turbine can be ensured to operate stably during the de-icing process.

Description

Technical Field

[0001] The present invention relates to the technical field of wind turbine deicing, and more particularly to a wind turbine blade deicing control method. Background Art

[0002] Wind power generation is one of the important sources of clean energy. However, in winter, the temperature is low. After rain and snow, the fan blade surface may freeze in whole or in part, which will cause the following effects:

[0003] 1. Change the blade airfoil: Due to uneven ice coverage, the aerodynamic characteristics of the blade are destroyed, resulting in reduced efficiency;

[0004] 2. Increase structural load: Ice increases the weight of the blades, causing imbalance and increasing the mechanical load on the blades and the entire machine;

[0005] 3. Reduce power generation efficiency: Blade deformation directly affects the wind energy capture rate and reduces power output;

[0006] 4. Shorten the life of the unit: Frequent changes in mechanical stress will accelerate the wear of fan components, especially the transmission system and connectors;

[0007] 5. Safety hazards: Ice shedding may cause damage to surrounding facilities or personnel, especially at high wind speeds;

[0008] Therefore, icing of wind turbine blades is a complex problem that must be solved. It not only affects the efficiency and safety of wind turbines, but also increases maintenance costs. Summary of the invention

[0009] The present invention provides a wind turbine blade de-icing control method, which solves the technical problem of de-icing the surface of wind turbine blades in the related art.

[0010] The present invention provides a wind turbine blade de-icing control method, comprising the following steps: step S101, real-time monitoring of the temperature of the surface of the wind turbine blade, constructing a first position temperature sequence according to a time interval v, wherein the first position temperature sequence comprises u units, and one unit represents the temperature of one corresponding position on the surface of the wind turbine blade;

[0011] Step S102, calculating the actual temperature of each position on the surface of the wind turbine blade according to the position temperature sequence, and generating a second position temperature sequence;

[0012] Step S103, obtaining all second position temperature sequences from the current to the past Y hours to calculate the ice thickness at each position on the surface of the wind turbine blade, and generating an ice thickness sequence, wherein the ice thickness sequence includes u units, and one unit represents the ice thickness at a corresponding position on the surface of the wind turbine blade;

[0013] Step S104, calculating an ice melting plan according to the ice thickness sequence;

[0014] The de-icing scheme includes the de-icing temperature at each position of the wind turbine blade;

[0015] Y, u and v are all custom parameters;

[0016] Wherein a temperature sensing device is arranged at each position inside the wind turbine blade, and the temperature of the surface of the wind turbine blade is obtained through the temperature sensing device at each position;

[0017] The steps of calculating the actual temperature at each position on the surface of the wind turbine blade include:

[0018] Step S201, obtaining the thermal conductivity of the wind turbine blade material and the material thickness and heat exchange coefficient at each position;

[0019] Step S202: Calculate the actual temperature of each position on the surface of the wind turbine blade , and its calculation formula is as follows:

[0020] ;

[0021] In the formula, Indicates the temperature obtained by the temperature sensing device; K represents the thermal conductivity of the wind turbine blade material; represents the ambient temperature; h represents the heat exchange coefficient of the wind turbine blade material; A represents the heat conduction area at the corresponding position; t represents the material thickness at the corresponding position of the wind turbine blade.

[0022] Furthermore, the step of calculating the ice thickness at various locations on the surface of the wind turbine blade includes:

[0023] Step S301, obtaining the external temperature, wind speed and humidity information from the current time to the past Y hours;

[0024] Step S302, presetting a first temperature change rate, selecting the actual temperature of each position on the surface of the wind turbine during the last time when the external temperature change rate exceeded the first temperature change rate;

[0025] The first temperature change rate is a custom parameter;

[0026] Step S303, calculating the actual temperature change rate of each position on the surface of the wind turbine generator, and determining whether the actual temperature change rate of each position on the surface of the wind turbine generator is equal to the temperature change rate of the outside;

[0027] If yes, it is determined that the corresponding position is frozen, and the process goes to step S304; if no, it is determined that it is not frozen, and the process ends;

[0028] Step S304, calculating the thickness of the ice layer at the icing location.

[0029] Furthermore, the method for obtaining the ice thickness at the icing location is specifically as follows:

[0030] m ice layer thicknesses are preset, each of which corresponds to a temperature change rate. The corresponding ice layer thickness is matched according to the actual temperature change rate at each position on the surface of the wind turbine blade during the last time when the external temperature change rate exceeded the first temperature change rate, and recorded as the initial ice layer thickness .

[0031] Furthermore, according to the initial ice thickness and the outside temperature , wind speed and humidity information Calculate current ice thickness , and its calculation formula is as follows:

[0032] ;

[0033] In the formula, Indicates a custom empirical coefficient; Indicates the dew point temperature of the environment; Indicates the time interval from the initial ice thickness to the current time; Indicates information about humidity The weight parameter is a custom parameter.

[0034] Further, the steps to calculate the ice melting solution are as follows:

[0035] Step S401, calculating the ice thickness change rate of each icing position according to the ice thickness at each position on the surface of the wind turbine in the ice thickness sequence , and its calculation formula is as follows:

[0036] ;

[0037] In the formula, Indicates the set ice melting temperature; Indicates the actual temperature at the freezing location; Indicates the material density at the corresponding position on the surface of the wind turbine blade; It represents the specific heat capacity at the corresponding position on the surface of the wind turbine blade; K represents the thermal conductivity of the wind turbine blade material; represents the initial thickness of the ice layer;

[0038] Step S402, judging whether the weight difference of ice between the blades of the wind turbine generator exceeds a preset weight difference according to the ice thickness sequence;

[0039] If it does not exceed, the heating and melting temperatures are set for all the icing locations according to the ice thickness change rate, so that the melting speeds of all the icing locations remain consistent; if it exceeds, the process proceeds to step S403;

[0040] Preset weight difference as custom parameter;

[0041] Step S403, first melt the ice on the heavier 1 / 2 blades, so that the weight of the ice layer on the three blades remains consistent, and then return to step S402.

[0042] Further, the steps to calculate the ice melting solution are as follows:

[0043] Step S501, constructing graph network data according to the ice thickness sequence;

[0044] Graph network data includes nodes and edges between nodes;

[0045] Nodes are generated by the information of ice thickness mapping at the icing location;

[0046] The existence of an edge between nodes indicates that: two ice locations are adjacent or the ice layers of two ice locations are connected;

[0047] Step S502, dividing the graph network data into a plurality of subgraphs, where no edge exists between nodes in two subgraphs;

[0048] Step S503: inputting a plurality of sub-graphs into the heating prediction model respectively, and outputting the predicted heating and ice-melting temperature of each ice formation position.

[0049] Furthermore, the training samples used to train the heating prediction model include:

[0050] Set an ice layer covering several icing locations, and heat one of the icing locations as sample data for a training sample;

[0051] The temperature changes of the icing location and other adjacent icing locations are obtained as sample labels of the training sample.

[0052] The beneficial effects of the present invention are: first, the parameters obtained by the temperature sensing device are corrected to avoid the temperature obtained being inconsistent with the actual temperature of the surface of the wind turbine; second, when melting the ice layer, the possible weight difference between the three blades is taken into account, and the synchronous ice melting operation is performed after the weight difference is smoothed. Compared with the general ice melting method, the ice can be processed without stopping the machine, and the wind turbine can be ensured to operate stably during the ice melting process. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is the overall flow chart of the present invention;

[0054] Figure 2 It is a flowchart of calculating the actual temperature of each position on the surface of a wind turbine blade according to the present invention;

[0055] Figure 3 It is a flowchart of calculating the ice thickness at various positions on the surface of a wind turbine blade according to the present invention;

[0056] Figure 4 is a flowchart of the calculation ice melting scheme of the present invention;

[0057] Figure 5 It is a flow chart of the second embodiment of the present invention. DETAILED DESCRIPTION

[0058] like Figure 1-Figure 4 As shown, the purpose of the first embodiment of the present invention is to treat the ice phenomenon on the surface of the wind turbine generator by heating and melting the ice. However, due to the huge size of the wind turbine generator and the difficulty in accurately locating the iced part, the surface can only be heated as a whole, which will waste a lot of energy. Therefore, a wind turbine blade ice melting control method is proposed, which includes the following steps:

[0059] First, it is necessary to obtain the temperature of the surface of the wind turbine blade. Therefore, in step S101, the temperature of the surface of the wind turbine blade is monitored in real time, and a first position temperature sequence is constructed according to the time interval v. The first position temperature sequence includes u units, and one unit represents the temperature of one corresponding position on the surface of the wind turbine blade.

[0060] Temperature sensing devices are arranged at various positions inside the wind turbine blades, and the surface temperature of the wind turbine blades is acquired through the temperature sensing devices at various positions. Preferably, the temperature sensing devices are arranged as temperature sensors, which belong to the prior art and are not described in detail here.

[0061] It should be noted that by setting temperature sensing devices at various positions inside the wind turbine blades, the inner surface temperature of the wind turbine blades can be obtained in real time. However, due to the influence of the material and structural design of the wind turbine blades, there are differences in heat conduction, so there will be differences in the temperature of the inner and outer surfaces.

[0062] From the above content, it can be known that the temperature obtained by the temperature sensing device needs to be corrected. Therefore, in step S102, the actual temperature of each position on the surface of the wind turbine blade is calculated according to the position temperature sequence, and a second position temperature sequence is generated;

[0063] The steps for calculating the actual temperature at each location on the surface of a wind turbine blade include:

[0064] Step S201, obtaining the thermal conductivity of the wind turbine blade material and the material thickness and heat exchange coefficient at each position;

[0065] Step S202, calculating the actual temperature of each position on the surface of the wind turbine blade , and its calculation formula is as follows:

[0066] ;

[0067] In the formula, Indicates the temperature obtained by the temperature sensing device; K represents the thermal conductivity of the wind turbine blade material; represents the ambient temperature; h represents the heat exchange coefficient of the wind turbine blade material; A represents the heat conduction area at the corresponding position; t represents the material thickness at the corresponding position of the wind turbine blade.

[0068] In addition, considering that the three blades of the wind turbine are in motion, the amount of ice (i.e., weight) on the surface of each blade will generally be different. When the difference is large, it will cause the wind turbine to be dynamically unbalanced. Therefore, it is also necessary to calculate the amount of ice at each position on the surface of the wind turbine blade in order to control the ice melting temperature later.

[0069] Based on this, step S103, obtain all second position temperature sequences from the current to the past Y hours to calculate the ice thickness at each position on the surface of the wind turbine blade, and generate an ice thickness sequence, the ice thickness sequence includes u units, and 1 unit represents the ice thickness at a corresponding position on the surface of the wind turbine blade;

[0070] In addition, due to the design of the wind turbine blade, the windward side needs to emphasize aerodynamic efficiency and needs to be designed as a smooth curved surface, while the leeward side only needs to reduce airflow diversion and maintain the stability of the blade, so it needs to be designed as a flat surface. Therefore, at the beginning of the design, the windward and leeward sides of the wind turbine have different shapes, smoothness and materials, so the temperature at different locations is the same, but the ice thickness is different. Therefore, the steps for calculating the ice thickness at various locations on the surface of the wind turbine blade include:

[0071] Step S301, obtaining the external temperature, wind speed and humidity information from the current time to the past Y hours;

[0072] Step S302, presetting a first temperature change rate, selecting the actual temperature of each position on the surface of the wind turbine during the last time when the external temperature change rate exceeded the first temperature change rate;

[0073] The first temperature change rate is a custom parameter;

[0074] Step S303, calculating the actual temperature change rate of each position on the surface of the wind turbine generator, and determining whether the actual temperature change rate of each position on the surface of the wind turbine generator is equal to the temperature change rate of the outside;

[0075] If yes, it is determined that the corresponding position is frozen, and the process goes to step S304; if no, it is determined that it is not frozen, and the process ends;

[0076] Step S304, calculating the thickness of the ice layer at the icing location.

[0077] It should be noted that when the outside temperature from the current to the past Y hours is obtained in step S301, it is required that the outside temperature in the Y hours should not exceed 0 degrees Celsius to avoid inaccurate judgment caused by melting of ice on the surface of the wind turbine blades;

[0078] The first temperature change rate indicates that the temperature changes rapidly in a short period of time, for example, the temperature rises or falls by 1 degree Celsius in one hour.

[0079] Then, the thickness of the ice layer can be calculated by the temperature change rate of the ice location and the external temperature, wind speed and humidity information from the current to the past Y hours. Therefore, the method for obtaining the thickness of the ice layer at the ice location is as follows:

[0080] m ice layer thicknesses are preset, each of which corresponds to a temperature change rate. The corresponding ice layer thickness is matched according to the actual temperature change rate at each position on the surface of the wind turbine blade during the last time when the external temperature change rate exceeded the first temperature change rate, and recorded as the initial ice layer thickness ;

[0081] According to the initial ice thickness and external temperature , wind speed and humidity information Calculate current ice thickness , and its calculation formula is as follows:

[0082] ;

[0083] In the formula, Indicates a custom empirical coefficient; Indicates the dew point temperature of the environment, that is, the temperature at which water vapor in the air begins to condense into ice; Indicates the time interval from the initial ice thickness to the current time; Indicates information about humidity The weight parameter is a custom parameter.

[0084] Since different ice thicknesses at different locations on the surfaces of different blades may lead to unbalanced operation of the wind turbine as a whole, it is necessary to adjust the ice melting temperature and time at different locations to ensure that the three blades can return to a balanced state as soon as possible. Therefore, in step S104, an ice melting scheme is calculated according to the ice thickness sequence.

[0085] The de-icing scheme includes the de-icing temperature at each position of the wind turbine blade;

[0086] The steps to calculate the ice melting plan are as follows:

[0087] Step S401, calculating the ice thickness change rate of each icing position according to the ice thickness at each position on the surface of the wind turbine in the ice thickness sequence , and its calculation formula is as follows:

[0088] ;

[0089] In the formula, Indicates the set ice melting temperature; Indicates the current actual temperature at the freezing location; Indicates the material density at the corresponding position on the surface of the wind turbine blade; It represents the specific heat capacity at the corresponding position on the surface of the wind turbine blade; K represents the thermal conductivity of the wind turbine blade material; represents the initial thickness of the ice layer;

[0090] Step S402, judging whether the weight difference of ice between the blades of the wind turbine generator exceeds a preset weight difference according to the ice thickness sequence;

[0091] If it does not exceed, the heating and melting temperatures are set for all the icing locations according to the ice thickness change rate, so that the melting speeds of all the icing locations remain consistent; if it exceeds, the process proceeds to step S403;

[0092] Preset weight difference as custom parameter;

[0093] Step S403, first melt the ice on the heavier 1 / 2 blades, so that the weight of the ice layer on the three blades remains consistent, and then return to step S402.

[0094] It is worth noting that since the thickness of the ice layer can reflect the weight of the ice layer to a certain extent, when calculating the weight of the ice layer through the thickness of the ice layer at each position, the thickness of each ice layer is added one by one and then multiplied by a proportional coefficient. The result is regarded as the weight of the ice layer. The proportional coefficient is obtained by multiplying the number of connected ice positions by the thermal conductivity area corresponding to each ice position.

[0095] Y, u and v are all custom parameters. Preferably, Y is set to 20, v is set to 10, and u is set according to the actual size of the wind turbine.

[0096] like Figure 5 As shown, the purpose of the second embodiment of the present invention is that, during the ice melting operation, ice layers at close locations may affect each other when melting. For example, if the ice layer at one location is thicker, the temperature when heating the ice layer for melting is higher, which will affect the surrounding ice locations. Therefore, the steps of calculating the ice melting scheme are as follows:

[0097] Step S501, constructing graph network data according to the ice thickness sequence;

[0098] Graph network data includes nodes and edges between nodes;

[0099] Nodes are generated by the information of ice thickness mapping at the icing location;

[0100] The existence of an edge between nodes indicates that: two ice locations are adjacent or the ice layers of two ice locations are connected;

[0101] Step S502, dividing the graph network data into a plurality of subgraphs, where no edge exists between nodes in two subgraphs;

[0102] Step S503: inputting a plurality of sub-graphs into the heating prediction model respectively, and outputting the predicted heating and ice-melting temperature of each ice formation position.

[0103] It should be noted that dividing the graph network data into several subgraphs can effectively reduce the amount of calculation and improve the calculation speed.

[0104] Before the heating prediction model is put into use, it needs to be trained. Therefore, the training samples used to train the heating prediction model include:

[0105] Set an ice layer covering several icing locations, and heat one of the icing locations as sample data for a training sample;

[0106] The temperature changes of the icing location and other adjacent icing locations are obtained as sample labels of the training sample.

[0107] The above describes an embodiment of the present embodiment, but the present embodiment is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present embodiment, ordinary technicians in this field can also make many forms, all of which are within the protection of the present embodiment.

Claims

1. A method for controlling ice melting of wind turbine blades, characterized in that: The following steps are involved: Step S101, real-time monitoring of the temperature of the surface of the wind turbine blade is performed, and a first position temperature sequence is constructed according to a time interval v, wherein the first position temperature sequence comprises u units, and one unit represents the temperature of one corresponding position on the surface of the wind turbine blade; Step S102, calculating the actual temperature of each position on the surface of the wind turbine blade according to the position temperature sequence, and generating a second position temperature sequence; Step S103, obtaining all second position temperature sequences from the current to the past Y hours to calculate the ice thickness at each position on the surface of the wind turbine blade, and generating an ice thickness sequence, wherein the ice thickness sequence includes u units, and one unit represents the ice thickness at a corresponding position on the surface of the wind turbine blade; Step S104, calculating an ice melting plan according to the ice thickness sequence; The de-icing scheme includes the de-icing temperature at each position of the wind turbine blade; Y, u and v are all custom parameters; Wherein a temperature sensing device is arranged at each position inside the wind turbine blade, and the temperature of the surface of the wind turbine blade is obtained through the temperature sensing device at each position; The steps of calculating the actual temperature at each position on the surface of the wind turbine blade include: Step S201, obtaining the thermal conductivity of the wind turbine blade material and the material thickness and heat exchange coefficient at each position; Step S202: Calculate the actual temperature of each position on the surface of the wind turbine blade , and its calculation formula is as follows: ； In the formula, Indicates the temperature obtained by the temperature sensing device; K represents the thermal conductivity of the wind turbine blade material; represents the ambient temperature; h represents the heat exchange coefficient of the wind turbine blade material; A represents the heat conduction area at the corresponding position; t represents the material thickness at the corresponding position of the wind turbine blade.

2. A wind turbine blade de-icing control method according to claim 1, characterized in that: The steps for calculating the ice thickness at various locations on the surface of a wind turbine blade include: Step S301, obtaining the external temperature, wind speed and humidity information from the current time to the past Y hours; Step S302, presetting a first temperature change rate, selecting the actual temperature of each position on the surface of the wind turbine during the last time when the external temperature change rate exceeded the first temperature change rate; The first temperature change rate is a custom parameter; Step S303, calculating the actual temperature change rate of each position on the surface of the wind turbine generator, and determining whether the actual temperature change rate of each position on the surface of the wind turbine generator is equal to the temperature change rate of the outside; If yes, it is determined that the corresponding position is frozen, and the process goes to step S304; if no, it is determined that it is not frozen, and the process ends; Step S304, calculating the thickness of the ice layer at the icing location.

3. A wind turbine blade de-icing control method according to claim 2, characterized in that: The method for obtaining the ice thickness at the icing location is as follows: m ice layer thicknesses are preset, each of which corresponds to a temperature change rate. The corresponding ice layer thickness is matched according to the actual temperature change rate at each position on the surface of the wind turbine blade during the last time when the external temperature change rate exceeded the first temperature change rate, and recorded as the initial ice layer thickness .

4. A wind turbine blade de-icing control method according to claim 3, characterized in that: According to the initial ice thickness and external temperature , wind speed and humidity information Calculate current ice thickness , and its calculation formula is as follows: ； In the formula, Indicates a custom empirical coefficient; Indicates the dew point temperature of the environment; Indicates the time interval from the initial ice thickness to the current time; Indicates information about humidity The weight parameter is a custom parameter.

5. The wind turbine blade de-icing control method according to claim 1, characterized in that: The steps to calculate the ice melting plan are as follows: Step S501, constructing graph network data according to the ice thickness sequence; Graph network data includes nodes and edges between nodes; Nodes are generated by the information of ice thickness mapping at the icing location; The existence of an edge between nodes indicates that: two ice locations are adjacent or the ice layers of two ice locations are connected; Step S502, dividing the graph network data into a plurality of subgraphs, where no edge exists between nodes in two subgraphs; Step S503: inputting a plurality of sub-graphs into the heating prediction model respectively, and outputting the predicted heating and ice-melting temperature of each ice formation position.

6. A wind turbine blade de-icing control method according to claim 5, characterized in that: The training samples used to train the heating prediction model include: Set an ice layer covering several icing locations, and heat one of the icing locations as sample data for a training sample; The temperature changes of the icing location and other adjacent icing locations are obtained as sample labels of the training sample.

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