Design method of maximum power point tracking power curve considering tracking performance of wind turbine

Abstract

The application discloses a maximum power point tracking power curve design method considering fan tracking performance, which is based on maximum power point tracking control of a type of power curve, and a new type of power curve is designed for the problem of poor wind energy capture efficiency caused by insufficient acceleration performance of the fan at low wind speed, and the power / torque instruction of the fan is a high power of the rotating speed. Compared with the traditional power curve based on the square of the rotating speed, the electromagnetic torque at low wind speed is greatly weakened, the unbalanced torque is increased, the acceleration performance of the fan is enhanced, and the wind energy capture efficiency of the fan is increased. The embodiment of the application compares the method with other two traditional maximum power point tracking control improvement methods, and verifies the effectiveness of the method.

Description

Technical Field

[0001] This invention belongs to the field of wind turbine control technology, and in particular, it is a maximum power point tracking power curve design method that takes into account the tracking performance of wind turbines. Background Technology

[0002] Maximum Power Point Tracking (MPPT) control based on power curves aims to capture maximum wind energy by adjusting the rotor speed to track the optimal rotational speed corresponding to different wind speeds, thereby ensuring the turbine operates at its maximum operating point. However, due to the rapid fluctuations in the tracked turbulent wind speed signal and the turbine's large moment of inertia, its slow dynamics make it difficult for the turbine to track changing wind speeds, resulting in wind energy capture losses. Considering the impact of turbine dynamics on wind energy capture, adjustments to the power curve (or power signal feedback, PSF) method are necessary.

[0003] The existing adaptive torque control (ATC) method based on the power curve method sets an additional torque gain to make the power curve flatter. By reducing the electromagnetic torque, it increases the unbalanced torque of the wind turbine, thereby enhancing the acceleration performance of the wind turbine and improving wind energy capture.

[0004] However, current research has found that its ability to enhance wind turbine performance is still limited by the power curve pattern of the square of the rotational speed. Its improvement in acceleration at high wind speeds is far greater than at low wind speeds. Considering that wind turbines inherently have insufficient aerodynamic torque at low wind speeds but greater aerodynamic torque at high wind speeds, this means that when there is a pressing need to improve wind turbine acceleration at low wind speeds, the acceleration effect is not significant. Conversely, the substantial enhancement of wind turbine acceleration at high wind speeds leads to excessive speed acceleration, resulting in a decrease in wind energy capture instead of an increase. Summary of the Invention

[0005] The purpose of this invention is to address the problems existing in the prior art by providing a maximum power point tracking power curve design method that considers the tracking performance of wind turbines. By providing a torque curve command based on a high power of the rotational speed, the acceleration capability of wind turbines at low wind speeds is effectively and significantly enhanced, thereby accelerating the MPPT process and improving wind energy capture.

[0006] The technical solution to achieve the objective of this invention is as follows: On the one hand, a maximum power point tracking power curve design method considering wind turbine tracking performance is provided, the method comprising the following steps:

[0007] Step 1: Obtain relevant parameters, including air density ρ, rotor radius R, fixed blade pitch angle β, moment of inertia J, and optimal tip speed ratio λ. optMaximum wind energy utilization coefficient C pmax ;

[0008] Step 2, Initialize parameters: Initial rotational speed ω ini Initial gain coefficient Ω, optimization period H k The number of samples n in each period;

[0009] Step 3, set the power curve command mode, including: Mode 1, traditional power curve command. Mode 2, new power curve instruction T e2 This refers to a torque command method based on higher powers of the rotational speed, which is related to the initial gain coefficient Ω.

[0010] Step 4: Sample the wind speed information of the current cycle's wind turbine operation and record the wind turbine rotation speed ω. r ;

[0011] Step 5, determine the current period H k Is it finished? If yes, proceed to step 6; otherwise, proceed to step 7.

[0012] Step 6: Calculate the equivalent optimal rotational speed average for the current wind speed period. And update the gain coefficient Proceed to step 3;

[0013] Step 7: Based on the relationship between the actual speed of the fan and the average value of the equivalent optimal speed, adaptively select the power curve command mode;

[0014] Step 8: Based on the selected power curve command mode, obtain the torque command value, and then return to execute step 4.

[0015] Furthermore, the torque command of the new power curve in step 3 is specifically in the following form:

[0016]

[0017] in,

[0018] Furthermore, in step 6, the equivalent optimal rotational speed average value... The specific calculation formula is as follows:

[0019]

[0020] In the formula, v i This represents the wind speed value from the i-th sample.

[0021] Furthermore, step 7, which involves adaptively selecting the power curve command mode based on the relationship between the actual speed of the wind turbine and the average equivalent optimal speed, specifically includes:

[0022] Calculate Ω and ω r The difference e = Ω - ω r Select the power curve command mode based on e:

[0023] When e≤0, select mode 1;

[0024] When e > 0, select mode 2.

[0025] On the other hand, a maximum power point tracking power curve design system considering wind turbine tracking performance is provided, the system comprising sequentially executing:

[0026] The first module is used to obtain relevant parameters, including air density ρ, rotor radius R, fixed blade pitch angle β, moment of inertia J, and optimal tip speed ratio λ. opt Maximum wind energy utilization coefficient C pmax ;

[0027] The second module is used to initialize parameters: initial rotational speed ω ini Initial gain coefficient Ω, optimization period H k The number of samples n in each period;

[0028] The third module is used to set the power curve command mode, including: Mode 1, traditional power curve command. Mode 2, new power curve instruction T e2 This refers to a torque command method based on higher powers of the rotational speed, which is related to the initial gain coefficient Ω.

[0029] The fourth module is used to sample the wind speed information of the wind turbine during the current cycle and record the wind turbine speed ω. r ;

[0030] The fifth module is used to determine the current period H. k If the process ends, proceed to module six; otherwise, proceed to module seven.

[0031] The sixth module is used to calculate the equivalent optimal average rotational speed for the current wind speed period. And update the gain coefficient Proceed to the third module;

[0032] The seventh module is used to adaptively select the power curve command mode based on the relationship between the actual speed of the wind turbine and the average value of the equivalent optimal speed.

[0033] The eighth module is used to obtain the torque command value based on the selected power curve command mode, and then return to execute the fourth module.

[0034] On the other hand, a computer device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the program, implements the maximum power point tracking power curve design method considering wind turbine tracking performance.

[0035] On the other hand, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the maximum power point tracking power curve design method considering wind turbine tracking performance.

[0036] Compared with the prior art, the significant advantages of this invention are:

[0037] 1) This invention abandons the traditional torque curve command method in the form of the square of the rotational speed. The designed curve can significantly enhance the acceleration capability of the wind turbine, thereby improving the wind energy capture efficiency.

[0038] 2) This invention provides an adaptive method for the gain coefficient under varying wind speeds, which can periodically update the gain coefficient according to changes in wind speed and has good adaptability to turbulent wind conditions.

[0039] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0040] Figure 1 The flowchart shows the maximum power point tracking power curve design method for wind turbine tracking performance in this invention.

[0041] Figure 2 This diagram compares the maximum power point tracking control design method of this invention, which considers wind turbine tracking performance, with other methods regarding speed trajectories. Figure 2 (a) in the text represents a typical low wind speed range. Figure 2 (b) in the text represents a typical high wind speed range.

[0042] Figure 3 This diagram compares the maximum power point tracking power curve design method of this invention, which considers wind turbine tracking performance, with other methods. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0044] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0045] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0046] Combination Figure 1 This invention provides a maximum power point tracking power curve design method considering wind turbine tracking performance, the method comprising the following steps:

[0047] Step 1: Obtain relevant parameters, including air density ρ, rotor radius R, fixed blade pitch angle β, moment of inertia J, and optimal tip speed ratio λ. opt Maximum wind energy utilization coefficient C pmax ;

[0048] Step 2, Initialize parameters: Initial rotational speed ω ini Initial gain coefficient Ω, optimization period H k The number of samples n in each period;

[0049] Step 3, set the power curve command mode, including: Mode 1, traditional power curve command. Mode 2, New Power Curve Instruction in, This invention presents a torque command method based on higher powers of rotational speed, differing from traditional power curve methods. The difference between the electromagnetic torque under traditional MPPT control and the electromagnetic torque under the new curve command is:

[0050]

[0051] It can be seen that as long as the actual rotational speed is less than the gain coefficient Ω, ΔT e If the value is greater than 0, the electromagnetic torque of the wind turbine will decrease, thus increasing the unbalanced torque of the wind turbine, thereby enhancing the acceleration capability of the wind turbine and improving wind energy capture.

[0052] Step 4: Sample the wind speed information of the current cycle's wind turbine operation and record the wind turbine rotation speed ω. r ;

[0053] Step 5, determine the current period H k Is it finished? If yes, proceed to step 6; otherwise, proceed to step 7.

[0054] Step 6: Calculate the equivalent optimal rotational speed average for the current wind speed period. And update the gain coefficient Proceed to step 3;

[0055] Here, considering that the wind turbine is in one cycle H m The maximum wind energy that can be captured is At this wind speed range, there must exist a constant value v. k , making Therefore v k This can be considered the equivalent optimal wind speed within that time period. Therefore, the equivalent optimal average rotational speed under the equivalent optimal wind speed can be calculated. as follows:

[0056]

[0057] Step 7: Based on the relationship between the actual speed of the wind turbine and the average value of the equivalent optimal speed, adaptively select the power curve command mode, specifically including:

[0058] Calculate Ω and ω r The difference e = Ω - ω r Select the power curve command mode based on e:

[0059] When e≤0, select mode 1. When the actual speed of the fan is greater than the equivalent optimal average speed, it means that the speed of the fan has reached the optimal speed and no further acceleration is needed. Therefore, the traditional power curve command can be selected.

[0060] When e > 0, select mode 2. When the equivalent optimal average speed of the wind turbine is greater than the actual speed, it means that the wind turbine has not yet reached the optimal speed. Therefore, it needs to be accelerated. Select the new power curve command, which can make the wind turbine accelerate quickly, thereby improving wind energy capture.

[0061] Step 8: Based on the selected power curve command mode, obtain the torque command value, and then return to execute step 4.

[0062] This invention provides a maximum power point tracking power curve design system considering wind turbine tracking performance, the system comprising the following sequentially executed functions:

[0063] The first module is used to obtain relevant parameters, including air density ρ, rotor radius R, fixed blade pitch angle β, moment of inertia J, and optimal tip speed ratio λ. opt Maximum wind energy utilization coefficient C pmax ;

[0064] The second module is used to initialize parameters: initial rotational speed ω ini Initial gain coefficient Ω, optimization period H k The number of samples n in each period;

[0065] The third module is used to set the power curve command mode, including: Mode 1, traditional power curve command. Mode 2, new power curve instruction T e2 This refers to a torque command method based on higher powers of the rotational speed, which is related to the initial gain coefficient Ω.

[0066] The fourth module is used to sample the wind speed information of the wind turbine during the current cycle and record the wind turbine speed ω. r ;

[0067] The fifth module is used to determine the current period H. k If the process ends, proceed to module six; otherwise, proceed to module seven.

[0068] The sixth module is used to calculate the equivalent optimal average rotational speed for the current wind speed period. And update the gain coefficient Proceed to the third module;

[0069] The seventh module is used to adaptively select the power curve command mode based on the relationship between the actual speed of the wind turbine and the average value of the equivalent optimal speed.

[0070] The eighth module is used to obtain the torque command value based on the selected power curve command mode, and then return to execute the fourth module.

[0071] Specific limitations regarding the design system for the maximum power point tracking (MPPT) power curve considering wind turbine tracking performance can be found in the limitations of the MPPT power curve design method for wind turbine tracking performance described above, and will not be repeated here. Each module in the aforementioned MPPT power curve design system considering wind turbine tracking performance can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the memory of a computer device as software, so that the processor can call and execute the corresponding operations of each module.

[0072] This invention provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it performs the following steps:

[0073] Step 1: Obtain relevant parameters, including air density ρ, rotor radius R, fixed blade pitch angle β, moment of inertia J, and optimal tip speed ratio λ. opt Maximum wind energy utilization coefficient C pmax ;

[0074] Step 2, Initialize parameters: Initial rotational speed ω ini Initial gain coefficient Ω, optimization period H k The number of samples n in each period;

[0075] Step 3, set the power curve command mode, including: Mode 1, traditional power curve command. Mode 2, new power curve instruction T e2 This refers to a torque command method based on higher powers of the rotational speed, which is related to the initial gain coefficient Ω.

[0076] Step 4: Sample the wind speed information of the current cycle's wind turbine operation and record the wind turbine rotation speed ω. r ;

[0077] Step 5, determine the current period H k Is it finished? If yes, proceed to step 6; otherwise, proceed to step 7.

[0078] Step 6: Calculate the equivalent optimal rotational speed average for the current wind speed period. And update the gain coefficient Proceed to step 3;

[0079] Step 7: Based on the relationship between the actual speed of the fan and the average value of the equivalent optimal speed, adaptively select the power curve command mode;

[0080] Step 8: Based on the selected power curve command mode, obtain the torque command value, and then return to execute step 4.

[0081] For specific limitations on each step, please refer to the limitations on the maximum power point tracking power curve design method considering wind turbine tracking performance mentioned above, which will not be repeated here.

[0082] This invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, performs the following steps:

[0083] Step 1: Obtain relevant parameters, including air density ρ, rotor radius R, fixed blade pitch angle β, moment of inertia J, and optimal tip speed ratio λ. opt Maximum wind energy utilization coefficient Cpmax ;

[0084] Step 2, Initialize parameters: Initial rotational speed ω ini Initial gain coefficient Ω, optimization period H k The number of samples n in each period;

[0085] Step 3, set the power curve command mode, including: Mode 1, traditional power curve command. Mode 2, new power curve instruction T e2 This refers to a torque command method based on higher powers of the rotational speed, which is related to the initial gain coefficient Ω.

[0086] Step 4: Sample the wind speed information of the current cycle's wind turbine operation and record the wind turbine rotation speed ω. r ;

[0087] Step 5, determine the current period H k Is it finished? If yes, proceed to step 6; otherwise, proceed to step 7.

[0088] Step 6: Calculate the equivalent optimal rotational speed average for the current wind speed period. And update the gain coefficient Proceed to step 3;

[0089] Step 7: Based on the relationship between the actual speed of the fan and the average value of the equivalent optimal speed, adaptively select the power curve command mode;

[0090] Step 8: Based on the selected power curve command mode, obtain the torque command value, and then return to execute step 4.

[0091] For specific limitations on each step, please refer to the limitations on the maximum power point tracking power curve design method considering wind turbine tracking performance mentioned above, which will not be repeated here.

[0092] The present invention will now be described in further detail with reference to the embodiments.

[0093] Example

[0094] The simulation model uses FAST (Fatigue, Aerodynamics, Structures, and Turbulence), an open-source professional wind turbine simulation software provided by the National Renewable Energy Laboratory (NREL) of the U.S. Department of Energy. The wind turbine model corresponds to the 0.6MW CART 3 model developed by NREL, and its relevant parameters are as follows.

[0095] Table 1 Main parameters of NREL 0.6MW CART3 wind turbine

[0096]

[0097] In the FAST software, the new electromagnetic torque command is set as follows:

[0098]

[0099] The parameter Ω is periodically updated based on changes in wind speed. The update rules are as follows:

[0100] The wind speed and rotational speed information of the fan during each cycle are sampled. At the end of the cycle, the equivalent optimal rotational speed average value for that wind speed period is calculated based on the sampled data. When the cycle ends, update Then calculate Ω and ω. r The difference e = Ω - ω r And select the power command mode according to the sign of e:

[0101] When e≤0, the traditional power command is selected; when e>0, the new power command is selected.

[0102] Based on measured wind speeds from the Goldwind system, 50 turbulent wind speed periods, each lasting 4 hours (including 24 periods of 10 minutes each), were generated. The average wind speed varied according to the measured wind speed (1 hour), and the turbulence intensity conformed to the ABC level. The results were validated using the professional simulation software FAST. The parameter iteration cycle was 10 minutes. Simulations were performed on each wind speed period using the traditional Power-Power-Focused (PSF) method, the Adaptive Torque Control (ATC) method, and the improved method proposed in this invention. The obtained wind energy capture efficiency was analyzed, and the average percentage increase in wind energy capture efficiency across the 50 wind speed periods was used as an indicator of the method's effectiveness.

[0103] Table 2 Comparison of different MPPT control methods

[0104]

[0105] As can be seen from Table 2, the method of the present invention is a significant improvement over the traditional PSF method and the adaptive torque method.

[0106] Specifically, a set of wind speed sequences was selected, and the wind turbine rotation speed trajectories in typical low-wind-speed and high-wind-speed ranges, as well as the wind energy capture efficiency in each cycle, were compared in detail.

[0107] like Figure 2As shown in (a), when the wind speed is low, this method has a stronger acceleration capability compared to the PSF and ATC methods. Therefore, the rotor speed decelerates more slowly when the wind speed decreases and accelerates more quickly when the wind speed increases. Consequently, its rotor speed trajectory is consistently higher than the other two methods, thus reserving stronger kinetic energy for the wind turbine to accelerate and track gradually increasing gusts. At high wind speeds, this method, compared to the traditional PSF method, can maintain a higher rotational speed level, thereby maximizing wind energy capture, such as... Figure 2 As shown in (b) of the diagram.

[0108] At the same time, by Figure 3 As shown, in this wind speed sequence, the method proposed in this invention achieves higher wind energy capture efficiency in almost every cycle, thereby improving the overall wind energy capture. In summary, the method proposed in this invention improves efficiency by 1.58% compared to the adaptive torque control method (adaptive torque control improves efficiency by 0.62% compared to the traditional PSF method).

[0109] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for designing a maximum power point tracking power curve considering wind turbine tracking performance, characterized in that, The method includes the following steps: Step 1: Obtain relevant parameters, including air density ρ, rotor radius R, fixed blade pitch angle β, moment of inertia J, and optimal tip speed ratio λ. opt Maximum wind energy utilization coefficient C pmax ; Step 2, Initialize parameters: Initial rotational speed ω ini Initial gain coefficient Ω, optimization period H k The number of samples n in each period; Step 3, set the power curve command mode, including: Mode 1, traditional power curve command. Mode 2, new power curve instruction T e2 This refers to a torque command method based on higher powers of the rotational speed, which is related to the initial gain coefficient Ω. Step 4: Sample the wind speed information of the current cycle's wind turbine operation and record the wind turbine rotation speed ω. r ; Step 5, determine the current period H k Is it finished? If so, proceed to step 6; otherwise, proceed to step 7. Step 6: Calculate the equivalent optimal rotational speed average for the current wind speed period. And update the gain coefficient Proceed to step 3; Step 7: Based on the relationship between the actual speed of the fan and the average value of the equivalent optimal speed, adaptively select the power curve command mode; Step 8: Based on the selected power curve command mode, obtain the torque command value, and then return to execute step 4. The specific form of the torque command for the new power curve in step 3 is as follows: in, 2. The maximum power point tracking power curve design method considering wind turbine tracking performance according to claim 1, characterized in that, Step 6: Efficient Optimal Rotational Speed ​​Average The specific calculation formula is as follows: In the formula, v i This represents the wind speed value from the i-th sample.

3. The maximum power point tracking power curve design method considering wind turbine tracking performance according to claim 1, characterized in that, Step 7, which involves adaptively selecting the power curve command mode based on the relationship between the actual speed of the wind turbine and the average equivalent optimal speed, specifically includes: Calculate Ω and ω r The difference e = Ω - ω r Select the power curve command mode based on e: When e≤0, select mode 1; When e > 0, select mode 2.

4. A maximum power point tracking power curve design system considering wind turbine tracking performance based on any one of the methods in claims 1 to 3, characterized in that, The system includes sequential execution of: The first module is used to obtain relevant parameters, including air density ρ, rotor radius R, fixed blade pitch angle β, moment of inertia J, and optimal tip speed ratio λ. opt Maximum wind energy utilization coefficient C pmax ; The second module is used to initialize parameters: initial rotational speed ω ini Initial gain coefficient Ω, optimization period H k The number of samples n in each period; The third module is used to set the power curve command mode, including: Mode 1, traditional power curve command. Mode 2, new power curve instruction T e2 This refers to a torque command method based on higher powers of the rotational speed, which is related to the initial gain coefficient Ω. The fourth module is used to sample the wind speed information of the wind turbine during the current cycle and record the wind turbine speed ω. r ; The fifth module is used to determine the current period H. k If the process ends, proceed to module six; otherwise, proceed to module seven. The sixth module is used to calculate the equivalent optimal average rotational speed for the current wind speed period. And update the gain coefficient Proceed to the third module; The seventh module is used to adaptively select the power curve command mode based on the relationship between the actual speed of the wind turbine and the average value of the equivalent optimal speed. The eighth module is used to obtain the torque command value based on the selected power curve command mode, and then return to execute the fourth module.

5. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the maximum power point tracking power curve design method considering wind turbine tracking performance as described in any of claims 1 to 3.

6. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by the processor, the program implements the maximum power point tracking power curve design method considering wind turbine tracking performance as described in any of claims 1 to 3.

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