A method, system and storage medium for thermal management of IGBT in a doubly-fed wind turbine converter

Abstract

The present invention relates to a method, system, and storage medium for thermal management of an IGBT in a doubly-fed wind turbine converter. The method comprises the following steps: obtaining real-time wind speed and calculating a first power; establishing a wind speed-junction temperature fitting curve based on corresponding junction temperature data at different wind speeds, and using the wind speed-junction temperature fitting curve to obtain a first wind speed range based on a junction temperature threshold range; decomposing and reconstructing the real-time wind speed using a wavelet packet algorithm, repeatedly decomposing and reconstructing the second wind speed; and calculating a second power using the current second wind speed when the second wind speed is within the first wind speed range; comparing the first power with the second power; and if the second power is smaller, setting a fourth power to the same value as the second power; and if the first power is smaller, determining whether the wind turbine is stalled and setting a fourth power based on the result; and finally, outputting the fourth power to the IGBT module of the doubly-fed wind turbine converter. Compared with existing technologies, the present invention has advantages such as high accuracy.

Description

Technical Field

[0001] The present invention relates to the field of converter thermal management, and in particular to a method, system and storage medium for thermal management of an IGBT of a doubly-fed wind turbine converter. Background Art

[0002] Wind turbine converters, as the hub of wind energy conversion systems, operate in random, intermittent conditions for extended periods. IGBTs (Insulated Gate Bipolar Transistors) are the modules with the highest failure rates, and are highly susceptible to cascading system failures. In offshore wind farms and mountainous wind tunnels, the machine-side converters of doubly fed induction generators (DFIGs) frequently switch between rectification and inverter modes, increasing IGBT junction temperature fluctuations. Although thermal management strategies for wind turbine converter systems under normal wind speed conditions are relatively mature, turbulent wind exhibits faster cycles and stronger intermittent characteristics on small timescales, such as s, compared to normal operating conditions. Therefore, for doubly fed wind turbines, studying machine-side converter thermal management control strategies under turbulent wind speeds is particularly important.

[0003] IGBT modules exposed to fluctuating wind speeds experience two types of junction temperature fluctuations: fundamental frequency and low-frequency. Fundamental frequency fluctuations are related to the inverter output frequency, while low-frequency fluctuations are often affected by wind speed fluctuations. Low-frequency fluctuations typically exhibit higher amplitudes within the inverter and have a greater impact on the lifespan of the IGBT module. Existing control strategies focus on suppressing fundamental frequency fluctuations, but their control range is limited. Low-frequency fluctuations account for a significant proportion of IGBT module lifespan in turbulent wind conditions. Their intensity can significantly impact lifespan within a short timeframe. Furthermore, the amplitude, mean, and frequency of these fluctuations exhibit random characteristics, making precise quantitative thermal management impossible. Summary of the Invention

[0004] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide a doubly-fed wind turbine converter IGBT thermal management method, system and storage medium.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A method for thermal management of an IGBT of a doubly-fed wind turbine converter comprises the following steps:

[0007] S1. Obtain real-time wind speed and calculate the first power;

[0008] S2. Establishing a wind speed-junction temperature fitting curve based on corresponding junction temperature data at different wind speeds, and using the wind speed-junction temperature fitting curve to obtain a first wind speed range based on a junction temperature threshold range;

[0009] S3. Decompose the real-time wind speed using a wavelet packet algorithm, reconstruct the decomposed result to obtain a second wind speed, repeatedly decompose and reconstruct the second wind speed, and when the second wind speed is within the first wind speed range, calculate the second power using the current second wind speed;

[0010] S4, comparing the first power and the second power. If the second power is less than or equal to the first power, proceed to step S5; if the second power is greater than the first power, proceed to step S6;

[0011] S5. Set the fourth power to the size of the second power, and execute step S8;

[0012] S6, determine whether the fan is stalled, if the fan is stalled, execute step S7; if the fan is not stalled, execute step S5;

[0013] S7. If the fan stalls, set the fourth power to the third power and execute step S8;

[0014] S8. Output the fourth power to the IGBT module of the doubly-fed wind turbine converter.

[0015] Furthermore, the first power P m The calculation expression is as follows:

[0016] P m =0.5ρπR 2 v 3 C P (λ,β)

[0017] Where, ρ represents the air density; R represents the radius of the wind wheel; v represents the wind speed; C P It represents the wind energy utilization coefficient related to the pitch angle β and the blade tip speed λ.

[0018] Furthermore, the specific expression for decomposing the real-time wind speed is as follows:

[0019]

[0020]

[0021] Where, Indicates the decomposed wind speed, h 0k Represents the coefficient of the low-frequency filter, h 1k Represents the coefficient of the high-frequency filter, w n Indicates the real-time angular velocity.

[0022] Furthermore, the steps for establishing the wind speed-junction temperature fitting curve are as follows:

[0023] Obtain the operating parameters of the converter at different wind speeds and calculate the switching loss and conduction loss based on the switching loss model;

[0024] Based on the wind turbine operating parameters and IGBT module parameters, the junction temperature at different wind speeds is calculated in combination with the switching loss and conduction loss;

[0025] All junction temperature and wind speed data are fitted to obtain the wind speed-junction temperature fitting curve.

[0026] Furthermore, the reconstructed second wind speed v e The calculation expression is as follows:

[0027]

[0028] Where, Indicates the corresponding decomposition times, h k-2l and g k-2l Both represent wind speed amplitude.

[0029] Furthermore, the discriminant expression for the fan stall is:

[0030]

[0031] Where w represents the current fan angular velocity, λ represents the fan blade tip speed, and λ stall represents the standard blade tip speed. Further, the second power P e The calculation expression is as follows:

[0032] P e =0.5ρπR 2 v e 3 C P (λ, β)

[0033] Where, ρ represents the air density; R represents the radius of the wind wheel; v e Indicates the second wind speed; C P It represents the wind energy utilization coefficient related to the pitch angle β and the blade tip speed λ.

[0034] Furthermore, the third power P o The calculation expression is as follows:

[0035] P o =K p (ω-ω o )+K I ∫(ω-ω o )+b

[0036]

[0037]

[0038] Where ω represents the current angular velocity, ω o Indicates the rated angular velocity, R indicates the radius of the wind wheel, K p , K I Represent the proportional coefficient and integral coefficient respectively; λ opt Indicates the optimal tip speed ratio for fan operation; They represent the mean and standard deviation of wind speed respectively, and T represents a sampling period.

[0039] A doubly-fed wind turbine converter IGBT thermal management system, characterized by comprising a data acquisition unit, a first processing unit, a second processing unit, a third processing unit, a fourth processing unit and a fifth processing unit connected in sequence:

[0040] The data acquisition module acquires real-time wind speed;

[0041] The first processing module calculates a first power according to the real-time wind speed;

[0042] The second processing module establishes a wind speed-junction temperature fitting curve according to the corresponding junction temperature data at different wind speeds, and obtains a first wind speed range using the wind speed-junction temperature fitting curve according to the junction temperature threshold range;

[0043] The third processing module decomposes the real-time wind speed using a wavelet packet algorithm, reconstructs the decomposed result to obtain a second wind speed, repeatedly decomposes and reconstructs the second wind speed, and when the second wind speed is within the first wind speed range, calculates the second power using the current second wind speed;

[0044] The fourth processing module compares the first power and the second power. If the second power is less than or equal to the first power, the fourth power is set to the second power. If the second power is greater than the first power, it is determined whether the fan is stalled.

[0045] If the fan stalls, the fourth power is set to the size of the third power;

[0046] If the fan is not stalled, the fourth power is set to the second power;

[0047] The fifth processing module outputs the fourth power obtained in the fourth module to the doubly-fed wind turbine converter IGBT module.

[0048] A computer storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the above-mentioned method for thermal management of an IGBT of a doubly-fed wind turbine converter.

[0049] Compared with the prior art, the present invention has the following advantages:

[0050] 1. The present invention obtains real-time wind speed, establishes a wind speed-junction temperature fitting curve, sets a first wind speed range according to the junction temperature threshold range, uses a wavelet packet algorithm to decompose and reconstruct the wind speed, sets a judgment standard, and selects different calculated powers as the fourth power output to the IGBT module according to the judgment result to implement thermal management. Since the real-time wind speed is a stable digital variable, accurate quantitative control is achieved by collecting this variable, thereby improving the accuracy of thermal management.

[0051] 2. The present invention uses a large number of standard operating parameters of the fan in the method and outputs power through multi-layer calculation to ensure the accuracy and scientificity of the data. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a schematic diagram of the process of the present invention.

[0053] Figure 2 This is the Foster thermal model diagram involved in the present invention.

[0054] Figure 3 This is the IGBT junction temperature curve without using this management method.

[0055] Figure 4 This is the IGBT junction temperature curve after using this management method. DETAILED DESCRIPTION

[0056] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0057] This embodiment provides a method for thermal management of IGBTs in a doubly-fed wind turbine converter, comprising the following steps:

[0058] Step S1: Obtain the real-time wind speed through the wind speed detection device and calculate the first power, the first power P m The calculation expression is as follows:

[0059] P m =0.5ρπR 2 v 3 C P (λ,β)

[0060] Where, ρ represents the air density; R represents the radius of the wind wheel; v represents the wind speed; C P It represents the wind energy utilization coefficient related to the pitch angle β and the blade tip speed λ.

[0061] Step S2: Establish a wind speed-junction temperature fitting curve based on the corresponding junction temperature data at different wind speeds. The specific establishment process is as follows:

[0062] First, set different wind speeds and obtain the converter operating parameters. Then, based on the switching loss model, the switching loss and conduction loss are calculated in combination with the converter operating parameters and wind speed. Then, based on the wind turbine operating parameters and the IGBT module data sheet parameters, the Foster thermal network model is established based on the switching loss and conduction loss, as shown in the following example: Figure 2 As shown, where T I1 、T D1 Represent the junction temperature of IGBT and diode respectively; T Ic 、T Dc Represent the case temperature of IGBT and diode respectively; T H is the radiator temperature; Ta is the ambient temperature; Z Ijc , Z Ich are the junction-case and case-heat sink thermal impedances of the IGBT, Z Djc , Z Dch are the junction-to-case and case-to-heat sink thermal impedances of the diode, Z h is the heat sink's thermal impedance. These thermal impedance parameters can be obtained from the manufacturer's datasheet. Switching loss and conduction loss are then used as input excitation signals to calculate the junction temperature. Finally, a wind speed-junction temperature fitting curve is constructed.

[0063] After obtaining the wind speed-junction temperature fitting curve, a first wind speed range is obtained according to a set junction temperature threshold range.

[0064] Step S3: Decompose the real-time wind speed using the wavelet packet algorithm. The specific expression of the decomposition is as follows:

[0065]

[0066]

[0067] Where, Indicates the decomposed wind speed, h 0k Represents the coefficient of the low-frequency filter, h 1k Represents the coefficient of the high-frequency filter, w n Indicates the real-time angular velocity of the fan.

[0068] After obtaining the decomposed wind speed, reconstruct the second wind speed v e The specific expression is as follows:

[0069]

[0070] Where, Indicates the corresponding decomposition times, h k-2l and g k-2l They represent the wind speed amplitude of odd-number decomposition and the wind speed amplitude of even-number decomposition respectively.

[0071] After the real-time wind speed is decomposed and reconstructed once to obtain the second wind speed, the second wind speed is compared with the first wind speed range obtained in step S2. If the second wind speed is not within the first wind speed range, the second wind speed is decomposed and reconstructed using the wavelet packet algorithm until the second wind speed is within the first wind speed range. At this time, the second wind speed is used to calculate the second power. The calculation expression is as follows:

[0072] P e =0.5ρπR 2 v e 3 C P (λ, β)

[0073] Where, ρ represents the air density; R represents the radius of the wind wheel; v e Indicates the second wind speed; C P It represents the wind energy utilization coefficient related to the pitch angle β and the blade tip speed λ.

[0074] Step S4: compare the first power and the second power. If the second power is less than or equal to the first power, execute step S5.

[0075] If the second power is greater than the first power, step S6 is executed;

[0076] Step S5, setting the fourth power to the second power, and executing step S8;

[0077] Step S6: Determine whether the fan is stalled. If the following determination expression is met, it is stalled:

[0078]

[0079] Where w represents the current fan angular velocity, λ represents the fan blade tip speed, and λ stall Indicates the standard blade tip speed, which is obtained from the data sheet provided by the manufacturer.

[0080] If the fan is determined to be stalled, step S7 is executed; if the fan is not stalled, step S5 is executed.

[0081] Step S7: Set the fourth power to the value of the third power, and execute step S8. The calculation expression of the third power is as follows:

[0082] P o =K p (ω-ω o )+K I ∫(ω-ω o )+b

[0083]

[0084]

[0085] Where ω represents the current angular velocity, ω o Indicates the rated angular velocity, R indicates the radius of the wind wheel, K p , K I Represent the proportional coefficient and integral coefficient respectively; λ opt Indicates the optimal tip speed ratio for fan operation; They represent the mean and standard deviation of wind speed respectively, and T represents a sampling period.

[0086] Step S8: output the fourth power to the IGBT module of the doubly-fed wind turbine converter.

[0087] Thus, the embodiment proposes a method for thermal management of IGBTs in a doubly-fed wind turbine converter, which is applicable to the theoretical method for junction temperature management within a small time scale under dynamic real-time wind speed. It adopts a thermal network model and is designed based on a wavelet packet algorithm, covering the management of wind speed, low-frequency junction temperature fluctuation amplitude, and mean value. Combined with limiting the junction temperature fluctuation threshold, the wind speed is decomposed and reconstructed, which reduces the low-frequency junction temperature fluctuation of the IGBT and extends the service life of the module while ensuring the stable operation of the unit. The junction temperature curves of the converter IGBT module before and after using this method are as follows: Figure 3 and Figure 4 As shown, it can be clearly seen that the junction temperature curve using this method is smoother and has smaller fluctuations.

[0088] This embodiment further provides a doubly-fed wind turbine converter IGBT thermal management system, comprising a data acquisition unit, a first processing unit, a second processing unit, a third processing unit, and a fourth processing unit connected in sequence:

[0089] The data acquisition module obtains the real-time wind speed;

[0090] The first processing module calculates the first power according to the real-time wind speed;

[0091] The second processing module establishes a wind speed-junction temperature fitting curve based on the corresponding junction temperature data at different wind speeds, and obtains a first wind speed range using the wind speed-junction temperature fitting curve based on the junction temperature threshold range;

[0092] The third processing module decomposes the real-time wind speed using a wavelet packet algorithm, reconstructs the decomposed result to obtain a second wind speed, repeatedly decomposes and reconstructs the second wind speed, and when the second wind speed is within the first wind speed range, calculates the second power using the current second wind speed;

[0093] The fourth processing module compares the first power and the second power, and if the second power is smaller, sets the fourth power to the same as the second power;

[0094] The fifth processing module outputs the fourth power obtained in the fourth module to the IGBT module of the doubly-fed wind turbine converter.

[0095] If the first power is small, determine whether the fan is stalled:

[0096] If the fan stalls, the fourth power is set to the size of the third power;

[0097] If the fan is not stalled, the fourth power is set to the second power.

[0098] This embodiment also provides a computer storage medium, wherein a computer-readable storage medium stores a computer program. When executed by a processor, the computer program implements the steps of a method for thermal management of IGBTs in a doubly-fed wind turbine converter. Any combination of one or more computer-readable media may be used. The computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium. The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples (a non-exhaustive list) of computer-readable storage media include: an electrical connection having one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In this document, a computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0099] The above describes in detail the preferred embodiments of the present invention. It should be understood that those skilled in the art can make numerous modifications and variations based on the concepts of the present invention without inventive effort. Therefore, any technical solutions that can be derived by those skilled in the art through logical analysis, reasoning, or limited experimentation based on the concepts of the present invention and the prior art should be within the scope of protection defined by the claims.

Claims

1. A method for thermal management of IGBTs in a doubly-fed wind turbine converter, characterized in that: The following steps are involved: S1. Obtain real-time wind speed and calculate the first power; S2. Establishing a wind speed-junction temperature fitting curve based on corresponding junction temperature data at different wind speeds, and using the wind speed-junction temperature fitting curve to obtain a first wind speed range based on a junction temperature threshold range; S3. Decompose the real-time wind speed using a wavelet packet algorithm, reconstruct the decomposed result to obtain a second wind speed, repeatedly decompose and reconstruct the second wind speed until the second wind speed is within the first wind speed range, and calculate the second power using the current second wind speed; S4, comparing the first power and the second power. If the second power is less than or equal to the first power, proceed to step S5; if the second power is greater than the first power, proceed to step S6; S5. Set the fourth power to the size of the second power, and execute step S8; S6, determine whether the fan is stalled, if the fan is stalled, execute step S7; if the fan is not stalled, execute step S5; S7. If the fan stalls, set the fourth power to the third power and execute step S8; S8, outputting the fourth power to the IGBT module of the doubly-fed wind turbine converter; The specific expression for decomposing the real-time wind speed is as follows: Where, Indicates the decomposed wind speed, h 0k Represents the coefficient of the low-frequency filter, h 1k Represents the coefficient of the high-frequency filter, w n Indicates the real-time angular velocity; The reconstructed second wind speed v e The calculation expression is as follows: Where, Indicates the corresponding decomposition times, h k-2l and g k-2l Both represent wind speed amplitude; The second power P e The calculation expression is as follows: P e =0.5ρπR 2 v e 3 C P (l,b) Where, ρ represents the air density; R represents the radius of the wind wheel; v e Indicates the second wind speed; C P represents the wind energy utilization coefficient related to the pitch angle β and blade tip speed λ; The third power P o The calculation expression is as follows: P o =K p (oh-oh o )+K I ∫(ω-ω o )+b Where ω represents the current angular velocity, ω o Indicates the rated angular velocity, R indicates the radius of the wind wheel, K p , K I Represent the proportional coefficient and integral coefficient respectively; λ opt Indicates the optimal tip speed ratio for fan operation; They represent the mean and standard deviation of wind speed respectively, and T represents a sampling period.

2. A doubly-fed wind turbine converter IGBT thermal management method according to claim 1, characterized in that: The first power P m The calculation expression is as follows: P m =0.5ρπR 2 v 3 C P (l,b) Where, ρ represents the air density; R represents the radius of the wind wheel; v represents the wind speed; C P It represents the wind energy utilization coefficient related to the pitch angle β and the blade tip speed λ.

3. The IGBT thermal management method for a doubly-fed wind turbine converter according to claim 1, characterized in that: The steps for establishing the wind speed-junction temperature fitting curve are as follows: Obtain the operating parameters of the converter at different wind speeds and calculate the switching loss and conduction loss based on the switching loss model; Based on the wind turbine operating parameters and IGBT module parameters, the junction temperature at different wind speeds is calculated in combination with the switching loss and conduction loss; All junction temperature and wind speed data are fitted to obtain the wind speed-junction temperature fitting curve.

4. The method for thermal management of IGBT of a doubly-fed wind turbine converter according to claim 1, characterized in that: The discriminant expression of the fan stall is: Where w represents the current fan angular velocity, λ represents the fan blade tip speed, and λ stall Indicates standard tip speed.

5. A doubly-fed wind turbine converter IGBT thermal management system, characterized in that: The system comprises a data acquisition unit, a first processing module, a second processing module, a third processing module, a fourth processing module and a fifth processing module connected in sequence: The data acquisition module acquires real-time wind speed; The first processing module calculates a first power according to the real-time wind speed; The second processing module establishes a wind speed-junction temperature fitting curve according to the corresponding junction temperature data at different wind speeds, and obtains a first wind speed range using the wind speed-junction temperature fitting curve according to the junction temperature threshold range; The third processing module decomposes the real-time wind speed using a wavelet packet algorithm, reconstructs the decomposed result to obtain a second wind speed, repeatedly decomposes and reconstructs the second wind speed until the second wind speed is within the first wind speed range, and calculates the second power using the current second wind speed; The fourth processing module compares the first power and the second power. If the second power is less than or equal to the first power, the fourth power is set to the second power. If the second power is greater than the first power, it determines whether the fan is stalled. If the fan stalls, the fourth power is set to the size of the third power; If the fan is not stalled, the fourth power is set to the second power; The fifth processing module outputs the fourth power obtained in the fourth module to the doubly-fed wind turbine converter IGBT module; The specific expression for decomposing the real-time wind speed is as follows: Where, Indicates the decomposed wind speed, h 0k Represents the coefficient of the low-frequency filter, h 1k Represents the coefficient of the high-frequency filter, w n Indicates the real-time angular velocity; The reconstructed second wind speed v e The calculation expression is as follows: Where, Indicates the corresponding decomposition times, h k-2l and g k-2l Both represent wind speed amplitude; The second power P e The calculation expression is as follows: P e =0.5ρπR 2 v e 3 C P (l,b) Where, ρ represents the air density; R represents the radius of the wind wheel; v e Indicates the second wind speed; C P represents the wind energy utilization coefficient related to the pitch angle β and blade tip speed λ; The third power P o The calculation expression is as follows: P o =K p (oh-oh o )+K I ∫(ω-ω o )+b Where ω represents the current angular velocity, ω o Indicates the rated angular velocity, R indicates the radius of the wind wheel, K p , K I Represent the proportional coefficient and integral coefficient respectively; λ opt Indicates the optimal tip speed ratio for fan operation; They represent the mean and standard deviation of wind speed respectively, and T represents a sampling period.

6. A computer storage medium, characterized in that The computer storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the IGBT thermal management method for a doubly-fed wind turbine converter according to any one of claims 1 to 4 are implemented.

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