Design method and calculation equipment for brake resistor of variable pitch system of wind turbine generator

Abstract

The invention discloses a design method for a brake resistor of a variable-pitch system of a wind turbine generator. The design method comprises the steps that simulation data of the variable-pitch system under the limiting working condition and the fatigue working condition are obtained through simulation of blades of the wind turbine generator; obtaining the short-time maximum power of the brake resistor when the variable-pitch motor is in a power generation state under the limiting working condition; the maximum resistance value and the minimum resistance value of the braking resistor are calculated, and the resistance value range of the braking resistor is determined; the power average value of the variable-pitch motor in the power generation state under all fatigue working conditions is obtained, the working condition with the maximum power average value is selected, and the power average value of the working condition serves as the maximum average power; calculating the maximum overload power of the brake resistor; comparing the short-time maximum power with the maximum overload power, and determining the minimum rated power allowed by the brake resistor design based on the larger one; and designing the brake resistor according to the resistance value range of the brake resistor and the minimum rated power allowed by the brake resistor design. The brake resistor designed by the method better meets the requirements of the actual operation condition of the unit.

Description

Technical Field

[0001] The present invention relates to the technical field of wind power generation, and in particular to a design method and a calculation device for a brake resistor of a variable pitch system of a wind turbine. Background Art

[0002] In wind turbines, the variable pitch system mainly plays the role of adjusting the input power of the wind rotor and the pneumatic brake, which is critical to the safe and stable operation of the wind turbine. For megawatt-class wind turbines, variable speed variable pitch technology is generally used, and the variable pitch system generally uses a frequency converter to drive the variable pitch motor to achieve the purpose of blade angle adjustment. In recent years, with the continuous increase in unit capacity and the continuous lengthening of blades, the root load of wind turbine blades has increased significantly, and the regenerative energy generated by the variable pitch motor during braking has increased significantly, posing a great hidden danger to the safety of the drive. Therefore, it is necessary to set a braking resistor to consume the regenerative energy generated by the variable pitch motor in the form of heat energy.

[0003] Since the pitch motor is adjusted in real time by the whole machine controller, affected by wind speed, wind direction, air density, and the whole machine power requirement, the operation and braking of all pitch motors are irregular, so the calculation of pitch motor regeneration energy is also different from other industrial inverters. However, the current design of the pitch system brake resistor is not accurate enough and cannot meet the actual operating conditions of the unit. Summary of the invention

[0004] A series of simplified concepts are introduced in the Summary of the Invention, which will be further described in detail in the Detailed Description of the Invention. The Summary of the Invention does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the scope of protection of the claimed technical solution.

[0005] In order to at least partially solve the above problem, according to a first aspect of the present invention, a method for designing a brake resistor of a wind turbine pitch control system is provided, comprising:

[0006] Through the unit blade simulation, the simulation data of the variable pitch system under extreme conditions and fatigue conditions are obtained, including the variable pitch motor speed and variable pitch motor torque under each condition;

[0007] According to the simulation data under extreme working conditions, the short-time maximum power P of the brake resistor when the pitch motor is in the power generation state under extreme working conditions is obtained. max ;

[0008] Based on the short-term maximum power P max The maximum resistance R of the brake resistor is calculated by using the brake circuit parameters of the pitch drive max ;

[0009] The minimum resistance R of the brake resistor is calculated based on the brake circuit parameters of the pitch drive. min ;

[0010] According to the maximum resistance R max and the minimum resistance R min Determine the resistance range of the brake resistor;

[0011] According to the simulation data under fatigue conditions, the average power of the variable pitch motor in the power generation state under all fatigue conditions is obtained, and the condition with the largest average power value is selected, and the average power value of this condition is taken as the maximum average power P avg ;

[0012] Based on the maximum average power P avg Calculate the maximum overload power P of the brake resistor by using the overload factor K of the brake resistor to be designed. max ';

[0013] Compare the short-term maximum power P max and the maximum overload power P max ', and determine the minimum rated power allowed by the brake resistor design based on the larger of the two;

[0014] The braking resistor is designed according to the resistance range of the braking resistor and the minimum rated power allowed by the braking resistor design.

[0015] Furthermore, the short-time maximum power P of the brake resistor when the pitch motor is in the power generation state under the extreme working condition is obtained according to the simulation data under the extreme working condition. max ,include:

[0016] The power of the pitch motor under each extreme working condition is calculated according to P = ((W*57.3)*60 / 360)*T / 9550, where P is power in kW, W is speed in rad, and T is torque in Nm;

[0017] The power of the pitch motor under each extreme working condition is counted, and the maximum value in the negative direction is selected as the maximum power of the pitch motor when it is in the power generation state, as the short-term maximum power P max .

[0018] Furthermore, the pitch drive braking circuit parameters include the braking start voltage U0 and the braking maximum current I max .

[0019] Further, the short-time maximum power P max The maximum resistance R of the brake resistor is calculated by using the brake circuit parameters of the pitch drive max ,include:

[0020] According to Rmax =(U0*U0) / P max Calculate the maximum resistance R max .

[0021] Furthermore, the minimum resistance R of the brake resistor is calculated based on the brake circuit parameters of the pitch drive. min ,include:

[0022] According to R min =U0 / I max Calculate the minimum resistance R min .

[0023] Furthermore, the power average value of the variable pitch motor in the power generation state under all fatigue conditions is obtained according to the simulation data under fatigue conditions, and the condition with the largest power average value is selected, and the power average value of the condition is taken as the maximum average power P avg ,include:

[0024] Based on the timing diagrams corresponding to the pitch motor torque and pitch motor speed under all fatigue conditions, the instantaneous power of the pitch motor at each time point under each fatigue condition is calculated according to P = ((W*57.3)*60 / 360)*T / 9550, where P is power (kW), W is speed (rad), and T is torque (Nm);

[0025] Calculate the average power under each fatigue condition based on the instantaneous power of the pitch motor at each time point under each fatigue condition;

[0026] Compare the power averages under all fatigue conditions and select the one with the largest value as the maximum average power P avg .

[0027] Further, the maximum average power P avg Calculate the maximum overload power P of the brake resistor by using the overload factor K of the brake resistor to be designed. max ',include:

[0028] Determine the derating factor S of the brake resistor and based on the maximum average power P avg Calculate the theoretical rated power P of the brake resistor using the derating factor S n ;

[0029] Based on the theoretical rated power P n and the overload factor K to calculate the maximum overload power P max '.

[0030] Further, the maximum average power P avg Calculate the maximum overload power P of the brake resistor by using the overload factor K of the brake resistor to be designed. max',include:

[0031] According to the maximum average power P avg The braking frequency ED% is determined by the ratio of the braking time of the pitch motor to the entire operating time of the pitch motor under the corresponding working condition;

[0032] According to P n =(P avg *ED%) / SCalculate the theoretical rated power P n ;

[0033] According to P max '=P n *K calculates the maximum overload power P max '.

[0034] Further, the comparison of the short-time maximum power P max and the maximum overload power P max ', and determine the minimum rated power allowed by the brake resistor design based on the larger of the two, including:

[0035] If the short-time maximum power P max Greater than the maximum overload power P max ', through P max / K determines the minimum rated power allowed by the braking resistor design.

[0036] If the maximum overload power P max 'Greater than the short-time maximum power P max , the theoretical rated power P n This is the minimum rated power allowed by the design of the braking resistor.

[0037] The present invention also provides a computing device, comprising:

[0038] a memory storing program instructions,

[0039] A processor, wherein the processor is configured to perform the above-mentioned design method when executing the program instructions.

[0040] The design method of the brake resistor of the variable pitch system of a wind turbine set of the present invention analyzes and calculates the load simulation data of the wind turbine variable pitch system, screens out the power of the variable pitch motor at the time of generating electricity under extreme conditions and fatigue conditions, calculates the brake resistor required for the power consumption according to the power of the variable pitch motor at the time of generating electricity, considers different working conditions when determining the resistance range and rated power of the brake resistor, can accurately calculate the power and resistance of the brake resistor, and the designed brake resistor better meets the requirements of the actual operating conditions of the wind turbine set. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The following drawings of the present invention are used as part of the present invention for understanding the present invention. The drawings show the embodiments of the present invention and their descriptions, and are used to explain the device and principle of the present invention. In the drawings,

[0042] Figure 1 A flow chart of a method for designing a brake resistor for a wind turbine pitch control system according to an embodiment of the present invention;

[0043] Figure 2 The figure is a schematic diagram of the working principle of the pitch motor and the brake resistor according to an embodiment of the present invention. DETAILED DESCRIPTION

[0044] Hereinafter, the present application will be described in more detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are not intended to limit the protection scope of the present application.

[0045] The present invention provides a design method for a brake resistor of a wind turbine pitch control system. Figure 1 As shown, the method includes:

[0046] Step 1: Through the unit blade simulation, obtain the simulation data of the variable pitch system under extreme conditions and fatigue conditions, including the variable pitch motor speed, variable pitch motor torque and the total reduction ratio of the variable pitch system.

[0047] The variable pitch system load simulation data is the main basis for designing the variable pitch system brake resistor. In one embodiment, the variable pitch load data of the unit fatigue condition and extreme condition can be simulated with a simulation cycle of 10 minutes, which serves as the basis for the subsequent design and calculation of the maximum power and resistance of the brake resistor.

[0048] Step 2: According to the simulation data under the extreme working condition, the short-time maximum power P of the brake resistor when the pitch motor is in the power generation state under the extreme working condition is obtained. max .

[0049] It should be noted that the brake resistor is used to consume regenerative energy, so the resistor will only work when the pitch motor is in the power generation state. Figure 2 As shown, when the motor torque is positive and the speed is negative, or the torque is negative and the speed is positive, the pitch motor is in the generating state and the braking resistor will be put into use.

[0050] In the embodiment of the present invention, the power of the pitch motor under each extreme working condition is calculated according to P=((W*57.3)*60 / 360)*T / 9550, where P is power (kW), W is speed (rad), and T is torque (Nm);

[0051] The power of the pitch motor under the above-mentioned extreme working conditions is counted, and the maximum value in the negative direction (the power with the largest absolute value among the powers with negative calculation results) is selected as the maximum power of the pitch motor when it is in the power generation state, and as the short-term maximum power P of the braking resistor. max The short-term maximum power P max It is the transient value of the simulation data of the variable pitch motor in the power generation state, so it belongs to the short-term energy maximum value.

[0052] Step 3: Based on the short-term maximum power P max The maximum resistance R of the brake resistor is calculated by using the brake circuit parameters of the pitch drive max .

[0053] In an embodiment of the present invention, the pitch drive braking circuit parameters include a braking start voltage U0 and a braking maximum current I max Based on this:

[0054] According to R max =(U0*U0) / P max Calculate the maximum resistance R of the brake resistor max .

[0055] Step 4: Calculate the minimum resistance R of the brake resistor based on the pitch drive brake circuit parameters min .

[0056] Specifically, according to R min =U0 / I max Calculate the minimum resistance R of the brake resistor min .

[0057] Step 5: According to the maximum resistance R max and the minimum resistance R min Determine the resistance range of the brake resistor.

[0058] This resistance range is the design range of the brake resistor: R min <R<R max , thus completing the first condition for the design of the brake resistor of the variable pitch system, that is, the determination of the resistance range. In the subsequent steps, the design calculation will be carried out for the second condition for the design of the brake resistor, that is, the rated power.

[0059] Step 6: According to the simulation data under fatigue conditions, the average power value of the variable pitch motor in the power generation state under all fatigue conditions is obtained, and the condition with the largest average power value is selected, and the average power value of this condition is taken as the maximum average power P avg .

[0060] In an embodiment of the present invention, based on the timing diagram corresponding to the pitch motor torque and the pitch motor speed under all fatigue conditions, the instantaneous power of the pitch motor at each time point under each fatigue condition is calculated according to P=((W*57.3)*60 / 360)*T / 9550, and the calculated instantaneous power is a single-point instantaneous power, where P is power (kW), W is speed (rad), and T is torque (Nm);

[0061] Based on the instantaneous power of the pitch motor at each time point under each fatigue condition, the average power under the fatigue condition is calculated, that is, the power required by the brake resistor under the condition;

[0062] Compare the power averages under all fatigue conditions and select the power average with the largest value as the maximum average power P avg , the maximum average power P avg It serves as the design basis for the rated power of the braking resistor.

[0063] Step 7: Based on the maximum average power P avg Calculate the maximum overload power P of the brake resistor by using the overload factor K of the brake resistor to be designed. max '.

[0064] According to a preferred embodiment of the present invention, since the brake resistor of the variable pitch system often adopts passive air cooling, taking into account the heat dissipation of the brake resistor and the design margin, the present invention preferably designs the resistance of the brake resistor according to the derating operation of the resistor, and uses the derating factor S when calculating the power required by the brake resistor. The derating factor S is calculated based on the temperature rise data of the brake resistor and the resistor temperature rise limit of the system design. The value range of S is 0.5-0.8, preferably 0.7.

[0065] Further preferably, the present invention also considers the maximum average power P avg The braking frequency ED% is determined by the ratio of the pitch motor braking time to the entire running time of the pitch motor under the corresponding working condition, that is, the ratio of the pitch motor generating time to the simulation time period.

[0066] Based on the above calculation, the maximum average power P avg , and combined with the above braking resistor derating factor S and braking frequency ED%, calculate the theoretical rated power of the braking resistor: P n =(P avg *ED%) / S.

[0067] Then based on the theoretical rated power P n and the overload factor K to calculate the maximum overload power: P max '=P n *K.

[0068] Step 8: Compare the short-time maximum power Pmax and the maximum overload power P max ', and determine the minimum rated power allowed by the brake resistor design based on the larger of the two.

[0069] Specifically, if the short-term maximum power P max Greater than the maximum overload power P max ', through P max / K determines the minimum rated power allowed by the braking resistor design;

[0070] If the maximum overload power P max 'Greater than the short-term maximum power P max , the theoretical rated power P n This is the minimum rated power allowed by the design of the braking resistor.

[0071] Step 9: Design a braking resistor according to the resistance range of the braking resistor and the minimum rated power allowed by the braking resistor design.

[0072] The design method of the brake resistor of the variable pitch system of the wind turbine set of the present invention analyzes and calculates the load simulation data of the wind turbine variable pitch system, selects the power of the variable pitch motor at the time of power generation under extreme working conditions and fatigue working conditions, calculates the brake resistor required for power consumption based on the power of the variable pitch motor at the time of power generation, considers different working conditions when determining the resistance range and rated power of the brake resistor, can accurately calculate the power and resistance of the brake resistor, and the designed brake resistor is more in line with the requirements of the actual operating conditions of the wind turbine set. Moreover, when calculating the power of the brake resistor, the derating factor and the braking frequency calculation are used to make the power design of the brake resistor more accurate, avoid the failure of the variable pitch drive caused by insufficient power of the brake resistor, and effectively ensure the safe operation of the unit.

[0073] The following takes the design and calculation process of the brake resistor of a certain type of pitch system as an example to explain the method of the present invention in detail:

[0074] Step 1: Perform blade simulation calculation according to the working conditions specified in the IEC61400 wind turbine standard to obtain simulation data of the variable pitch system under extreme working conditions and fatigue conditions;

[0075] Step 2: Count the simulation data of each extreme working condition and obtain the short-term maximum power P of the brake resistor when the pitch motor is in the power generation state. max Appears in DLC-cb-17 condition, under which P max =29.23kW;

[0076] Step 3: Based on the short-term maximum power P maxThe maximum resistance of the brake resistor is calculated by using the brake circuit parameters of the pitch drive (brake start voltage U0 = 760V): R max =(760*760) / 29.23=19.76Ω.

[0077] Step 4: Based on the pitch drive brake circuit parameters (brake maximum current I max =100A) Calculate the minimum resistance of the brake resistor: R min =760 / 100=7.6Ω.

[0078] Step 5: Determine the resistance range of the brake resistor: 7.6Ω<R<19.76Ω.

[0079] Step 6: According to the simulation data under fatigue conditions, the average power of the variable pitch motor in the power generation state under all fatigue conditions is obtained. The average power value is the largest in condition DLC-jc-06. The maximum average power P under this condition is determined. avg =2.72kW.

[0080] Step 7: Calculate the maximum overload power P max ', the derating factor S is 0.7, the braking resistor opening frequency ED% under the working condition DLC-jc-06 = 4129 / 12000 = 34%, from which the theoretical rated power P of the braking resistor is obtained n =(2.72*34%) / 0.7=1.32kW, according to the overload factor k of the brake resistor to be designed is 20, calculate the maximum overload power: P max '=1.32*20=26.42kW.

[0081] Step 8: Maximum overload power P max ' is less than the short-term maximum power P max , so based on the short-term maximum power P max Determine the minimum rated power allowed by the braking resistor design, that is, P max / K=29.28 / 20=1.46kW.

[0082] Step 9: Design a brake resistor according to the resistance range of the brake resistor 7.6Ω<R<19.76Ω and the minimum rated power of 1.46kW allowed by the brake resistor design. In this embodiment, the brake resistor adopts two resistors in parallel, the resistance of a single resistor is 24Ω, and the power is 1kW. Therefore, the total resistance after parallel connection is 12Ω, which meets the above resistance range; the power after parallel connection is 2kW, which meets the minimum rated power requirement allowed by the above brake resistor design, and retains a certain design margin.

[0083] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software may depend on the specific application and design constraints of the technical solution. The technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the embodiments of the present disclosure.

[0084] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0085] In the embodiments disclosed herein, the disclosed methods and products (including but not limited to devices, equipment, etc.) can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units can be only a logical function division. There can be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, and the indirect coupling or communication connection of devices or units can be electrical, mechanical or other forms.

[0086] The present invention has been described through the above-mentioned embodiments, but it should be understood that the above-mentioned embodiments are only for the purpose of example and description, and are not intended to limit the present invention to the scope of the described embodiments. In addition, it can be understood by those skilled in the art that the present invention is not limited to the above-mentioned embodiments, and more variations and modifications can be made according to the teachings of the present invention, and these variations and modifications all fall within the scope of the protection claimed by the present invention. The protection scope of the present invention is defined by the attached claims and their equivalents.

Claims

1. A design method for a brake resistor of a wind turbine pitch system, characterized in that: include: Through the unit blade simulation, the simulation data of the variable pitch system under extreme conditions and fatigue conditions are obtained, including the variable pitch motor speed and variable pitch motor torque under each condition; According to the simulation data under extreme working conditions, the short-time maximum power P of the brake resistor when the pitch motor is in the power generation state under extreme working conditions is obtained. max ; Based on the short-term maximum power P max The maximum resistance R of the brake resistor is calculated by using the brake circuit parameters of the pitch drive max ; The minimum resistance R of the brake resistor is calculated based on the brake circuit parameters of the pitch drive. min ; According to the maximum resistance R max and the minimum resistance R min Determine the resistance range of the brake resistor; According to the simulation data under fatigue conditions, the average power of the variable pitch motor in the power generation state under all fatigue conditions is obtained, and the condition with the largest average power value is selected, and the average power value of this condition is taken as the maximum average power P avg ; Based on the maximum average power P avg Calculate the maximum overload power P of the brake resistor by using the overload factor K of the brake resistor to be designed. max '; Compare the short-term maximum power P max and the maximum overload power P max ', and determine the minimum rated power allowed by the brake resistor design based on the larger of the two; The braking resistor is designed according to the resistance range of the braking resistor and the minimum rated power allowed by the braking resistor design.

2. The design method according to claim 1, characterized in that: The short-time maximum power P of the brake resistor when the pitch motor is in the power generation state under the extreme working condition is obtained according to the simulation data under the extreme working condition. max ,include: The power of the pitch motor under each extreme working condition is calculated according to P = ((W*57.3)*60 / 360)*T / 9550, where P is power in kW, W is speed in rad, and T is torque in Nm; The power of the pitch motor under each extreme working condition is counted, and the maximum value in the negative direction is selected as the maximum power of the pitch motor when it is in the power generation state, as the short-term maximum power P max .

3. The design method according to claim 1, characterized in that: The braking circuit parameters of the pitch drive include the braking start voltage U0 and the braking maximum current I max .

4. The design method according to claim 3, characterized in that: The short-term maximum power P max The maximum resistance R of the brake resistor is calculated by using the brake circuit parameters of the pitch drive max ,include: According to R max =(U0*U0) / P max Calculate the maximum resistance R max .

5. The design method according to claim 3, characterized in that: The minimum resistance R of the brake resistor is calculated based on the brake circuit parameters of the pitch drive. min ,include: According to R min =U0 / I max Calculate the minimum resistance R min .

6. The design method of the wind turbine pitch system brake resistor according to claim 1 is characterized in that: The power average value of the variable pitch motor in the power generation state under all fatigue conditions is obtained according to the simulation data under fatigue conditions, and the condition with the largest power average value is selected, and the power average value of the condition is taken as the maximum average power P avg ,include: Based on the timing diagrams corresponding to the pitch motor torque and pitch motor speed under all fatigue conditions, the instantaneous power of the pitch motor at each time point under each fatigue condition is calculated according to P = ((W*57.3)*60 / 360)*T / 9550, where P is power (kW), W is speed (rad), and T is torque (Nm); Calculate the average power under each fatigue condition based on the instantaneous power of the pitch motor at each time point under each fatigue condition; Compare the power averages under all fatigue conditions and select the one with the largest value as the maximum average power P avg .

7. The design method of the wind turbine pitch system brake resistor according to claim 6 is characterized in that: The maximum average power P avg Calculate the maximum overload power P of the brake resistor by using the overload factor K of the brake resistor to be designed. max ',include: Determine the derating factor S of the brake resistor and based on the maximum average power P avg Calculate the theoretical rated power P of the brake resistor using the derating factor S n ; Based on the theoretical rated power P n and the overload factor K to calculate the maximum overload power P max '.

8. The design method of the wind turbine pitch control system brake resistor according to claim 7, characterized in that: The maximum average power P avg Calculate the maximum overload power P of the brake resistor by using the overload factor K of the brake resistor to be designed. max ',include: According to the maximum average power P avg The braking frequency ED% is determined by the ratio of the braking time of the pitch motor to the entire operating time of the pitch motor under the corresponding working condition; According to P n =(P avg *ED%) / SCalculate the theoretical rated power P n ; According to P max '=P n *K calculates the maximum overload power P max '.

9. The method for designing a brake resistor for a wind turbine pitch control system according to claim 7 or 8, characterized in that: The comparison of the short-time maximum power P max and the maximum overload power P max ', and determine the minimum rated power allowed by the brake resistor design based on the larger of the two, including: If the short-time maximum power P max Greater than the maximum overload power P max ', through P max / K determines the minimum rated power allowed by the braking resistor design. If the maximum overload power P max 'Greater than the short-term maximum power P max , the theoretical rated power P n This is the minimum rated power allowed by the design of the braking resistor.

10. A computing device, characterized in that include: a memory storing program instructions, A processor, wherein the processor is configured to perform the design method according to any one of claims 1 to 9 when executing the program instructions.

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