Fan blade zoned heating de-icing control method

Abstract

The application provides a fan blade partition heating deicing control method, which comprises the following steps: S1. Dividing a fan blade into N heating zones from the front end of the blade to the root of the blade, and forming an arithmetic sequence in the length from the front end to the root; S2. Arranging an electric heating strip in each heating zone; S3. Obtaining the parameters of the environment where the fan blade is located, and determining the driving current of the heating deicing according to the fan blade environment parameters; and S4. Controlling the electric heating strip to work according to the driving current. The N zones from the end to the root of the fan blade are formed in the length, and then the layout modes of the heating strips in each zone are different, so that the local heating of the fan blade is formed, the deicing effect is effectively ensured, and the deicing loss is avoided from being increased.

Description

Technical Field

[0001] This invention relates to a de-icing control method, and more particularly to a wind turbine blade zone heating de-icing control method. Background Technology

[0002] Wind power, as a clean and renewable energy source, has been widely used globally. However, in cold and humid climates, wind turbine blades are prone to icing, which not only adversely affects the aerodynamic performance of the blades but also threatens the operational stability and safety of the entire wind turbine system.

[0003] Blade icing alters the aerodynamic shape of the blade surface, reducing the power output efficiency of the wind turbine. Furthermore, blade icing increases its weight, causing blade imbalance and leading to problems such as vibration and increased mechanical stress. In severe cases, it can even cause wind turbine shutdown or equipment failure.

[0004] In existing technologies, wind turbine blade de-icing is achieved through heating, which rapidly heats the blade surface. However, this heating-based de-icing method neglects the issue of uniform ice distribution on the blades. Ice accumulation is most severe at the leading edge, with the ice thickness decreasing linearly from the tip to the root. Because different locations on the blade require varying power for de-icing, the overall de-icing method cannot guarantee synchronization and results in a less even temperature distribution on the blade surface, leading to increased energy consumption.

[0005] Therefore, in order to solve the above-mentioned technical problems, it is urgent to propose a new technical approach. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a method for controlling the zoned heating and de-icing of wind turbine blades. By dividing the wind turbine blade into N zones with equal lengths from the end to the root, and then arranging the heating strips in each zone differently, the wind turbine blades are heated in a zoned manner. This method can effectively ensure the de-icing effect while avoiding increased de-icing losses.

[0007] The present invention provides a method for controlling zoned heating and de-icing of wind turbine blades, comprising the following steps:

[0008] S1. Divide the fan blades into N heating zones from the tip to the root; and the lengths of the heating zones from the tip to the root form an arithmetic sequence;

[0009] S2. Install electric heating strips in each heating zone;

[0010] S3. Obtain the parameters of the environment where the wind turbine blades are located, and determine the driving current for heating and de-icing based on the environmental parameters of the wind turbine blades;

[0011] S4. Control the operation of the electric heating strip based on the driving current.

[0012] Furthermore, the drive current is determined using the following method:

[0013] Determine the critical de-icing power density:

[0014] q cr =I i 2 R i =q R +q C +q wv ;

[0015] Where: q cr For the critical power density of de-icing, I i R represents the de-icing drive current of the i-th partition. i Let q represent the resistance of the i-th partition. R For the power loss due to radiative heat transfer, q C For convective heat transfer loss power, q wv This is the power density required for melting ice;

[0016] The de-icing driving current I is obtained by solving the critical de-icing power density. i .

[0017] Furthermore, the radiative heat transfer loss power q R Determined using the following method:

[0018] q R =εσ(T) a +273) 3 (TT a );

[0019] Where: ε is the radiation coefficient, σ represents the Boltzmann constant, and T a T represents the ambient temperature, and T represents the temperature of the fan blades.

[0020] Furthermore, the convective heat transfer loss power q C Determined using the following method:

[0021] q C =h×(TT) a Where: h is the air convection coefficient; T a T represents the ambient temperature, and T represents the temperature of the fan blades.

[0022] Furthermore, the air convection coefficient h is determined using the following method:

[0023] h = ρ·c·v rel ·st, where: ρ is the air density, v relc is the relative wind speed and c is the specific heat capacity of the air.

[0024] intermediate variables intermediate variables Where l is the chord pitch of the wind turbine blades, and η is the air viscosity coefficient.

[0025] Furthermore, the electric heating strip comprises, from top to bottom, a heat insulation layer, a heat-conducting layer, and a base layer;

[0026] The base layer is attached to the wind turbine blades and is made of epoxy resin;

[0027] The heating layer is a PI electrothermal film.

[0028] Furthermore, the heating zones of the fan blades, from the tip to the root, are sequentially numbered 1-N;

[0029] The length direction of the electric heating strips in heating zone 1 and heating zone 2 is consistent with the length direction of the fan blades;

[0030] The length direction of the electric heating strips in heating zones 3 to N is perpendicular to the length direction of the fan blades.

[0031] The beneficial effects of the present invention are as follows: By dividing the wind turbine blade into N zones with an arithmetic sequence of length from the end to the root, and then arranging the heating strips in each zone differently, the wind turbine blade is heated in a localized manner. Furthermore, the driving current of each zone is determined based on the heating resistance value and environmental parameters of each zone. This effectively ensures the de-icing effect and efficiency while avoiding increased de-icing losses. Attached Figure Description

[0032] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0033] Figure 1 This is a flowchart of the present invention.

[0034] Figure 2 This is a schematic diagram showing the layout of the heating strips in different zones of the present invention.

[0035] Figure 3 This is a schematic diagram of the structure of the electric heating strip of the present invention. Detailed Implementation

[0036] The present invention will be further described in detail below:

[0037] The present invention provides a method for controlling zoned heating and de-icing of wind turbine blades, comprising the following steps:

[0038] S1. Divide the fan blade 1 from the tip to the root into N heating zones; and the lengths of the heating zones from the tip to the root form an arithmetic sequence; the length difference between two adjacent zones is based on the radius of the blade (i.e., its total length) divided by 20, and the length of the first zone is determined according to the actual operating conditions; specifically:

[0039] The heating zones of the fan blades, from the tip to the root, are numbered 1-N.

[0040] The length direction of the electric heating strips in heating zone 1 and heating zone 2 is consistent with the length direction of the fan blades;

[0041] The length direction of the electric heating bars from heating zone 3 to heating zone N is perpendicular to the length direction of the fan blades. Furthermore, the number of electric heating bars in heating zones 1 and 2 decreases progressively, as does the number of electric heating bars in heating zones 3 to N. Additionally, the lengths of heating zones 1-N also decrease progressively, forming an arithmetic sequence.

[0042] S2. Install electric heating strips 2 in each heating zone;

[0043] S3. Obtain the parameters of the environment where the wind turbine blades are located, and determine the driving current for heating and de-icing based on the environmental parameters of the wind turbine blades;

[0044] S4. Control the operation of the electric heating strips based on the driving current. Using the above method, the fan blades are divided into N zones with equal lengths from the tip to the root. The heating strips in each zone are arranged differently, thus achieving localized heating of the fan blades. Furthermore, the driving current for each zone is determined based on its heating resistance and environmental parameters. This effectively ensures the de-icing effect and efficiency while avoiding increased de-icing losses.

[0045] In this embodiment, the drive current is determined by the following method:

[0046] Determine the critical de-icing power density:

[0047] q cr =I i 2 R i =q R +q C +q wv ;

[0048] Where: q cr For the critical power density of de-icing, I i R represents the de-icing drive current of the i-th partition. i Let q represent the resistance of the i-th partition. R For the power loss due to radiative heat transfer, q C For convective heat transfer loss power, qwv This is the power density required for melting ice;

[0049] The de-icing driving current I is obtained by solving the critical de-icing power density. i The current magnitude is controlled by the existing heating drive circuit, which will not be elaborated here.

[0050] Specifically: the radiative heat transfer loss power q R Determined using the following method:

[0051] q R =εσ(T) a +273) 3 (TT a );

[0052] Where: ε is the radiation coefficient, σ represents the Boltzmann constant, and T a T represents the ambient temperature, and T represents the temperature of the fan blades.

[0053] The convective heat transfer loss power q C Determined using the following method:

[0054] q C =h×(TT) a Where: h is the air convection coefficient; T a T represents the ambient temperature, and T represents the temperature of the fan blades.

[0055] The air convection coefficient h is determined using the following method:

[0056] h = ρ·c·v rel ·st, where: ρ is the air density, v rel c is the relative wind speed and c is the specific heat capacity of the air.

[0057] intermediate variables intermediate variables Where l is the chord pitch of the wind turbine blades, and η is the air viscosity coefficient.

[0058] In the above, the power density q required for ice melting is... wv If the ice level cannot be specifically represented by a mathematical model, it is necessary to assess the ice level in each area using existing ice monitoring methods (such as image monitoring). Then, the power required to melt the ice under this ice level is determined. By using the above method, the driving current required for heating can be assessed more accurately, thereby avoiding increased energy consumption and saving energy while ensuring the de-icing effect.

[0059] In this embodiment, the electric heating strip comprises, from top to bottom, a heat insulation layer 21, a heating layer 22, a heat-conducting layer 23, and a base layer 24; the top and bottom layers mentioned above are... Figure 3The direction shown in the diagram is up and down. Since the blade has two sides and electric heating strips are installed on both sides, the direction shown in the diagram is used as the reference for up and down.

[0060] The base layer is attached to the wind turbine blades and is made of epoxy resin;

[0061] The heating layer is a PI electrothermal film.

[0062] The insulation layer uses existing insulation materials to prevent heat loss, the heat-conducting layer uses thermally conductive silicone to distribute heat evenly, and the base layer provides adhesion between the heat-conducting layer, the insulation layer, the heat-generating layer and the surface of the fan blades.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method of fan blade zonal heating de-icing control, the method comprising: The method comprises the following steps: ​ S1. Dividing the fan blade into N heating zones from the tip end of the blade to the root of the blade; and the lengths of the heating zones from the tip end to the root form an arithmetic sequence; S2. Setting an electric heating strip in each heating zone; S3. Obtaining the parameters of the environment in which the fan blade is located, and determining the driving current for heating and deicing according to the fan blade environmental parameters; S4. Controlling the electric heating strip to work according to the driving current; The driving current is determined by the following method: Determine the critical deicing power density: ； wherein: is the critical de-icing power density, represents the de-icing drive current of the i-th section, represents the resistance of the i-th section, is the power loss due to radiation heat transfer, is the power loss due to convection heat transfer, is the power density required for de-icing. The driving current for de-icing is solved from the critical de-icing power density ; The radiative heat loss power is determined by the method: ； wherein: is the emissivity, represents the Boltzmann constant, is the ambient temperature, T is the fan blade temperature; The convective heat loss power is determined by the method: ; where: is the air convection coefficient; is the ambient temperature, T is the fan blade temperature; The air convection coefficient is determined by the method : where: for air density, for air relative wind speed, c is the air specific heat capacity; intermediate variable ; intermediate variable ; wherein is the chord distance of the fan blade, is the air viscosity coefficient.

2. The method of claim 1, wherein: The electric heating strip comprises, from top to bottom, a heat insulation layer, a heating layer, a heat conduction layer, and a base layer; The base layer is attached to the fan blade, and the base layer is epoxy resin; The heating layer is a PI electric heating film.

3. The method of claim 1, wherein: The heating zones of the fan blade from the tip end of the blade to the root of the blade are 1-N in sequence; The length direction of the electric heating strip of the heating zone 1 and the heating zone 2 is consistent with the length direction of the fan blade; The length direction of the electric heating strip of the heating zone 3 to the heating zone N is perpendicular to the length direction of the fan blade.

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