A method and system for determining short-circuit demagnetization verification scenarios for permanent magnet wind turbines
By introducing the joint probability distribution of wind speed and ambient temperature into the design of permanent magnet wind turbines, the short-circuit demagnetization verification scenario is optimized, solving the problem of overly conservative design in existing technologies and achieving improvements in power density and torque density.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SUZHOU UNIV
- Filing Date
- 2026-04-07
- Publication Date
- 2026-07-31
AI Technical Summary
In existing technologies, the design of permanent magnet wind turbines uses extremely rare extreme scenarios as the short-circuit demagnetization verification benchmark, which leads to an overly conservative design that restricts the improvement of power density and torque density, and fails to take into account the actual probability distribution characteristics of wind speed and ambient temperature.
By obtaining the joint probability density function of wind speed and ambient temperature of the target wind field, multiple candidate verification scenarios are determined, the output power under each scenario is calculated, and the expected value equation is constructed to solve the final short-circuit demagnetization verification scenario to optimize the design.
While ensuring overall reliability, the power density and torque density of the permanent magnet wind turbine have been improved, achieving a more scientific design and avoiding excessive redundancy.
Smart Images
Figure CN121980824B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of permanent magnet wind turbine technology, and in particular to a method and system for determining short-circuit demagnetization verification scenarios for permanent magnet wind turbines. Background Technology
[0002] Wind energy, as an important clean energy source, plays a crucial role in the global energy structure transformation. Permanent magnet wind turbines (hereinafter referred to as "generators") have become the mainstream model of wind turbine generators due to their advantages such as high efficiency, high power density, and high reliability. However, the permanent magnet materials in generators face the risk of irreversible demagnetization (hereinafter referred to as "demagnetization") under certain operating conditions. This directly affects the performance, safety, and service life of the generator, and is a critical issue that must be considered in generator design.
[0003] The main factors leading to permanent magnet demagnetization can be summarized into two points: excessively high temperature and a strong reverse demagnetizing magnetic field. Short circuit faults, especially three-phase short circuits, are typical conditions that generate strong demagnetizing magnetic fields. When a short circuit occurs under the harsh conditions of full generator load and highest ambient temperature, the stator current can reach 4-5 times the rated current, and the resulting reverse magnetic field can easily cause irreversible demagnetization of the permanent magnets. Therefore, in traditional generator design theory, to ensure absolute safety and reliability, a stringent verification standard is generally adopted: requiring the generator to remain demagnetized even when a short circuit occurs under the "worst-case" of full load and highest ambient temperature. If the design cannot meet this criterion, it is necessary to limit the temperature of the windings and permanent magnets by reducing the stator current, etc., to improve the anti-demagnetization capability.
[0004] Existing research on short-circuit demagnetization verification largely focuses on simulating extreme current conditions. For example, Professor A. Popa's team at the Polytechnic University of Timișoara in Romania verified generator demagnetization at twice the rated current. Professor TM Jahns' team at the University of Wisconsin-Madison in the United States verified the demagnetization at three times the rated current amplitude on the d-axis, thus simulating the characteristics of short-circuit current. These studies all attempt to cover all possible short-circuit risks by setting a sufficiently stringent current condition, which is essentially consistent with the verification approach of the "worst-case scenario."
[0005] However, this traditional design criterion has significant limitations. It uses an extremely low-probability event as the design boundary condition. While theoretically guaranteeing absolute safety, this results in overly conservative generator designs, severely restricting further improvements in generator power density and torque density. In reality, wind speed and ambient temperature in a wind farm are not constant values but follow certain probability distributions (e.g., wind speed is often described by a Weibull distribution, and ambient temperature can be fitted by a normal distribution), and there is a correlation between the two. This means that the scenario of "generator at full load and highest ambient temperature" is extremely unlikely to occur in actual operation. From the perspective of multiple generators throughout the entire lifecycle of a wind farm, the vast majority of generators will never encounter a short-circuit fault under this extreme scenario during their service life. Even if a short circuit occurs, the low wind speed and temperature at the time may not be enough to cause demagnetization, or the degree of demagnetization may be very slight.
[0006] In summary, the existing technology has the following main shortcomings:
[0007] 1. Overly conservative design criteria: Using the extremely rare scenario of "generator at full load and highest ambient temperature" as the verification benchmark for short-circuit demagnetization, although it ensures reliability at the theoretical level, directly leads to excessive redundancy in generator design, which severely restricts the improvement of its power density and torque density, and fails to achieve optimal utilization of material performance.
[0008] 2. Neglecting the probabilistic characteristics of operating conditions: Existing technologies fail to incorporate the actual probability distribution characteristics of key factors such as wind speed and ambient temperature into design considerations. The probability of short-circuit demagnetization, a risk event, and its impact on generator output performance are still unclear. This makes the scientific and reasonable selection of a short-circuit demagnetization verification scenario during the design phase a pressing technical challenge. Currently, there are no reports in publicly available literature that consider the probabilistic characteristics of short-circuit demagnetization when selecting verification scenarios. Summary of the Invention
[0009] To address this issue, this invention provides a method and system for determining the short-circuit demagnetization verification scenario for permanent magnet wind turbines. This system solves the problem in the prior art where the generator design is too conservative and the improvement of power density is limited because the extremely low-probability scenario of "generator at full load and highest ambient temperature" is used as the demagnetization verification benchmark.
[0010] To address the aforementioned technical problems, embodiments of the present invention provide a method for determining the short-circuit demagnetization verification scenario of a permanent magnet wind turbine, the method comprising:
[0011] Obtain the joint probability density function of wind speed and ambient temperature for the target wind field;
[0012] Based on the joint probability density function, multiple candidate verification scenarios are determined, and each candidate verification scenario corresponds to a set of wind speed values and ambient temperature values.
[0013] Calculate the output power of the permanent magnet wind turbine after a short-circuit fault occurs in each candidate verification scenario;
[0014] Based on the joint probability density function and the output power, an expected value equation is constructed to characterize the overall output level of the permanent magnet wind turbine.
[0015] Solve the expected value equation, and determine the candidate verification scenarios corresponding to the wind speed and ambient temperature values that satisfy the expected value equation as the final short-circuit demagnetization verification scenarios.
[0016] Preferably, obtaining the joint probability density function of wind speed and ambient temperature of the target wind field specifically includes:
[0017] Collect historical wind speed data and historical ambient temperature data for the target wind field;
[0018] Determine the probability distribution models for wind speed and ambient temperature respectively;
[0019] Based on the probability distribution model of wind speed and the probability distribution model of ambient temperature, and considering the correlation between wind speed and ambient temperature, the joint probability density function is constructed.
[0020] Preferably, the step of calculating the output power of the permanent magnet wind turbine after a short-circuit fault occurs in each candidate verification scenario specifically includes:
[0021] For each candidate verification scenario, the three-phase short-circuit process of the permanent magnet wind turbine under that scenario is simulated, and the degree of irreversible demagnetization of the permanent magnet caused by the short-circuit current is calculated.
[0022] Based on the aforementioned degree of demagnetization, a model of a demagnetized permanent magnet wind turbine generator is established;
[0023] Under the preset rated operating conditions, the rated current is passed into the demagnetized permanent magnet wind turbine model, and its output electromagnetic power and stator-side losses are calculated.
[0024] Based on the electromagnetic power and stator-side losses, the output power of the permanent magnet wind turbine after short-circuit demagnetization in the candidate verification scenario is calculated.
[0025] Preferably, the preset rated operating conditions specifically include: a preset maximum wind speed value and a preset maximum ambient temperature value.
[0026] Preferably, the degree of demagnetization is characterized by a torque loss percentage, which is the ratio of the difference between the average electromagnetic torque before and after demagnetization under the same stator current to the average electromagnetic torque before demagnetization.
[0027] Preferably, the expected value equation is the weighted sum of the output power corresponding to all candidate verification scenarios and their occurrence probabilities, which is equal to the output power corresponding to the finally determined verification scenario;
[0028] The probability of occurrence of each candidate verification scenario is determined by the joint probability density function.
[0029] Preferably, the expected value equation is specifically expressed as:
[0030] ;
[0031] in, to for Output power corresponding to each candidate verification scenario to for The probability of occurrence of each candidate verification scenario For the final verification scenario The corresponding output power.
[0032] This invention also provides a system for determining short-circuit demagnetization verification scenarios for permanent magnet wind turbines. This system is used to implement the aforementioned method for determining short-circuit demagnetization verification scenarios for permanent magnet wind turbines, specifically including:
[0033] The joint probability density acquisition module is used to obtain the joint probability density function of wind speed and ambient temperature of the target wind field.
[0034] The candidate scene determination module is used to determine multiple candidate verification scenes based on the joint probability density function, and each candidate verification scene corresponds to a set of wind speed values and ambient temperature values.
[0035] The output power calculation module is used to calculate the output power of the permanent magnet wind turbine after a short circuit fault occurs in each candidate verification scenario.
[0036] The expected value equation construction module is used to construct an expected value equation characterizing the overall output level of the permanent magnet wind turbine based on the joint probability density function and the output power.
[0037] The verification scenario selection module is used to solve the expected value equation and determine the candidate verification scenarios corresponding to the wind speed and ambient temperature values that satisfy the expected value equation as the final short-circuit demagnetization verification scenarios.
[0038] This invention also provides an electronic device, which includes a processor, a memory, and a bus system. The processor and the memory are connected through the bus system. The memory is used to store instructions, and the processor is used to execute the instructions stored in the memory to realize the method for determining the short-circuit demagnetization verification scenario of the permanent magnet wind turbine described above.
[0039] This invention also provides a computer storage medium storing a computer software product, the computer software product including several instructions to cause a computer device to execute the method for determining the short-circuit demagnetization verification scenario of the permanent magnet wind turbine described above.
[0040] As can be seen from the above technical solutions, this invention application has the following beneficial effects:
[0041] (1) This invention abandons the practice of using the extremely low probability scenario of "generator at full load and ambient temperature at the highest" as the sole verification benchmark in traditional design methods. By introducing the joint probability distribution characteristics of wind speed and ambient temperature, the verification scenario is changed from the absolute most severe working condition to a reasonable working condition based on statistical probability. This effectively avoids design redundancy caused by excessive pursuit of absolute safety under extreme working conditions, thereby significantly improving the power density and torque density of permanent magnet wind turbines while ensuring overall reliability.
[0042] (2) This invention quantifies the probability of occurrence of different wind speed and ambient temperature combinations by constructing a joint probability density function, and combines the output power of the permanent magnet wind turbine after short-circuit demagnetization under each scenario to construct an expected value equation to characterize the overall output level of the permanent magnet wind turbine. This method quantifies and analyzes the randomness of short-circuit demagnetization risk and its impact on the performance of the permanent magnet wind turbine, enabling the selection of verification scenarios to move from empirical judgment to scientific calculation, and providing a more realistic theoretical basis for the design of permanent magnet wind turbines.
[0043] (3) This invention proposes a clear short-circuit demagnetization verification scenario determination equation, that is, the final verification scenario is determined by solving the mathematical expectation of the output power. This determination criterion is logically clear and highly operable. Designers only need to calculate the unique verification scenario (specific wind speed and ambient temperature value) based on the actual wind field data, avoiding the ambiguity and uncertainty caused by the overly general scenario selection in traditional methods, and has high engineering application value. Attached Figure Description
[0044] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Referring to the drawings will make the features and advantages of the present invention clearer. The drawings are illustrative and should not be construed as limiting the present invention in any way. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:
[0045] Figure 1 This is a flowchart of a method for determining a short-circuit demagnetization verification scenario for a permanent magnet wind turbine provided by the present invention;
[0046] Figure 2 This is a schematic diagram illustrating the probability distribution of wind speed and permanent magnet temperature in different wind fields in this invention.
[0047] Figure 3 This is a schematic diagram of a permanent magnet wind turbine part of the present invention;
[0048] Figure 4 This is a schematic diagram of the torque loss distribution caused by short-circuit demagnetization under different wind speeds and permanent magnet temperatures in this invention.
[0049] Figure 5 This is a schematic diagram of the output power distribution of the permanent magnet wind turbine under short-circuit demagnetization at different wind speeds and permanent magnet temperatures in this invention.
[0050] Figure 6 This is a block diagram of a system for determining a short-circuit demagnetization verification scenario for a permanent magnet wind turbine provided by the present invention. Detailed Implementation
[0051] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0052] Example 1: To address the problem in existing technologies where the use of a highly improbable scenario—"generator at full load and highest ambient temperature"—as the demagnetization verification benchmark leads to overly conservative generator designs and limited power density improvements, such as... Figure 1 As shown, this invention proposes a method for determining the short-circuit demagnetization verification scenario of a permanent magnet wind turbine, the method comprising:
[0053] Step S1: Obtain the joint probability density function of wind speed and ambient temperature for the target wind field.
[0054] This step first requires collecting long-term historical wind speed and ambient temperature data for the target wind field. Then, probability distribution models for wind speed and ambient temperature are determined respectively. In practical applications, the probability distribution characteristics of wind speed are a crucial consideration in wind turbine design. Most studies use statistical models for fitting, such as Rayleigh, beta, and Weibull distributions, with the two-parameter Weibull distribution being the most widely used. For the probability distribution of ambient temperature, statistical models, such as the normal distribution, can also be used to effectively fit meteorological data.
[0055] Finally, considering the correlation between wind speed and ambient temperature, a joint probability density function can be constructed based on the probability distribution models of wind speed and ambient temperature. This function forms the basis for all subsequent calculations and analyses; it quantitatively describes different wind speeds. and ambient temperature The probability of a combination occurring in the target wind field.
[0056] Step S2: Determine multiple candidate verification scenarios based on the joint probability density function.
[0057] Based on the joint probability density function obtained in step S1 We can discretize wind speed and ambient temperature within their respective value ranges to determine multiple candidate verification scenarios. Each candidate verification scenario uniquely corresponds to a set of wind speed values. and ambient temperature value These candidate scenarios cover the entire range from common to extreme operating conditions, providing a foundation for subsequent quantitative analysis.
[0058] Step S3: Calculate the output power of the permanent magnet wind turbine after a short-circuit fault occurs in each candidate verification scenario.
[0059] This step is the core of the invention, aiming to quantify the performance loss that would occur to the permanent magnet wind turbine in each candidate scenario if short-circuit demagnetization were to occur. Specifically, it includes the following sub-steps:
[0060] First, for each candidate verification scenario, a three-phase short-circuit process of the permanent magnet wind turbine under that scenario is simulated, and the degree of irreversible demagnetization of the permanent magnet caused by the short-circuit current is calculated. In permanent magnet wind turbines, short-circuit conditions, especially three-phase short circuits, are the main conditions for demagnetization verification. Permanent magnet wind turbines typically have a large back electromotive force and low impedance. Under full load, the peak short-circuit current can reach 4-5 times the rated current, and is mainly concentrated on the negative d-axis, which easily leads to demagnetization. In this embodiment, the degree of demagnetization can be characterized by the percentage of torque loss, that is, the percentage loss of the average electromagnetic torque before demagnetization relative to the torque before demagnetization under the same stator current. Figure 4 The diagram illustrates the torque loss caused by short-circuit demagnetization under different wind speeds and permanent magnet temperatures. It should be noted that since the degree of demagnetization is directly related to the permanent magnet temperature, our analysis focuses more on the combination of different wind speeds and permanent magnet temperatures, such as... Figure 2 The probability distribution diagram of wind speed and permanent magnet temperature shown is derived from the joint probability density function. The conversion.
[0061] Secondly, based on the aforementioned demagnetization degree, a demagnetized permanent magnet wind turbine model is established. For each candidate verification scenario, the original permanent magnet wind turbine model (e.g., [model name missing]) is modified according to the calculated demagnetization degree. Figure 3 The model of the permanent magnet wind turbine shown is modified to obtain a new model that can reflect the performance after demagnetization.
[0062] Then, under the preset rated operating conditions, a rated current is applied to the demagnetized permanent magnet wind turbine model, and its output electromagnetic power and stator-side losses are calculated. The preset rated operating conditions refer to the maximum capacity operating conditions expected during the design of the permanent magnet wind turbine, and in this embodiment, they specifically include a preset maximum wind speed value. and highest ambient temperature value For example, the maximum wind speed is 25 m / s and the maximum ambient temperature is 75℃. Under these conditions, a rated current (e.g., rated current amplitude 14992 A, current angle 196.8°) is passed through the stator winding of the demagnetized permanent magnet wind turbine model, and the output electromagnetic torque is calculated. Stator-side losses .
[0063] Finally, based on the electromagnetic power and stator-side losses, the output power of the permanent magnet wind turbine after short-circuit demagnetization in this candidate verification scenario is calculated. The calculation formula is as follows: By iterating through all candidate verification scenarios, we can obtain a set of output power values, such as... Figure 5 The diagram shows the output power distribution of a permanent magnet wind turbine after short-circuit demagnetization under different wind speeds and permanent magnet temperatures. Figure 5 The effects of different demagnetization conditions on the final output power are demonstrated.
[0064] Step S4: Based on the joint probability density function and the output power, construct the expected value equation to characterize the overall output level of the permanent magnet wind turbine.
[0065] After obtaining the probability of occurrence of each candidate verification scenario (derived from the joint probability density function) (Decision) and the output power after short-circuit demagnetization in this scenario. Then, we can construct an expected value equation. The core idea of this equation is that the combined impact of all possible short-circuit demagnetization scenarios on the overall output level of the permanent magnet wind turbine can be represented by a weighted average value, and this average value should be equal to the output power under the specific verification scenario that we finally selected as the design benchmark.
[0066] Specifically, the expected value equation is the weighted sum of the output power and the probability of occurrence of all candidate verification scenarios, which equals the output power of the finally determined verification scenario. The probability of occurrence of each candidate verification scenario is determined by the joint probability density function.
[0067] In a preferred embodiment of the present invention, the expected value equation is specifically expressed as:
[0068] ;
[0069] in, to for Output power corresponding to each candidate verification scenario to for The probability of occurrence of each candidate verification scenario For the final verification scenario The corresponding output power. The left side of the equation is actually the mathematical expectation of the output power.
[0070] Step S5: Solve the expected value equation, and determine the candidate verification scenarios corresponding to the wind speed value and ambient temperature value that satisfy the expected value equation as the final short-circuit demagnetization verification scenarios.
[0071] Solving the above equation means finding one scenario among all candidate scenarios. Its output power It is exactly equal to the mathematical expectation of the output power for all scenarios. The wind speed value corresponding to this scenario. and ambient temperature value This refers to the short-circuit demagnetization verification scenario that this invention aims to determine, which can characterize the overall output level of a permanent magnet wind turbine.
[0072] Generally, the degree of short-circuit demagnetization will not exceed 10%. Therefore, the difference in the degree of short-circuit demagnetization occurring under different wind speeds and ambient temperatures is limited, while the probability of occurrence varies considerably among different wind fields and ambient temperatures. Therefore, when solving this equation, The result always tends to be the output power corresponding to the wind speed and ambient temperature of the wind field with the highest probability.
[0073] As a specific example, combined with Figures 3 to 5 The data shown, obtained through the aforementioned steps, yields a mathematical expectation of 9960.2 kW for the output power. After comparison with... Figure 5 , Figure 2 Comparison reveals that the wind speed and permanent magnet temperature corresponding to an output power close to the expected value are approximately 6 m / s and 60°C, respectively, with a probability of 0.95%. Figure 2 The point with the highest probability is 1.01%, which is very close to the previous one. Therefore, in this example, the scenario corresponding to a wind speed of 6 m / s and a permanent magnet temperature of 60°C can be determined as the final short-circuit demagnetization verification scenario.
[0074] As can be seen from the above technical solutions, this invention proposes a method for determining the short-circuit demagnetization verification scenario for permanent magnet wind turbines. This method, by introducing the joint probability distribution of wind speed and ambient temperature, transforms the risk of short-circuit demagnetization from the traditional "worst-case scenario" verification to a probability-based "overall output level" verification. This effectively improves the power density of permanent magnet wind turbines while ensuring overall output reliability. The technical solution of this invention can guide the selection of reasonable values from the probability distribution of wind speed and ambient temperature during the design process of permanent magnet wind turbines, maximizing output power while ensuring overall output reliability, and overcoming the constraint of short-circuit demagnetization risk on the improvement of torque density of permanent magnet wind turbines.
[0075] Example 2: Figure 6 As shown, this invention provides a system for determining the short-circuit demagnetization verification scenario of a permanent magnet wind turbine. This system is used to implement the method for determining the short-circuit demagnetization verification scenario of a permanent magnet wind turbine as described in Embodiment 1 above, specifically including:
[0076] The joint probability density acquisition module 100 is used to acquire the joint probability density function of wind speed and ambient temperature of the target wind field.
[0077] The candidate scene determination module 200 is used to determine multiple candidate verification scenes based on the joint probability density function, and each candidate verification scene corresponds to a set of wind speed values and ambient temperature values.
[0078] The output power calculation module 300 is used to calculate the output power of the permanent magnet wind turbine after a short circuit fault occurs in each candidate verification scenario.
[0079] The expected value equation construction module 400 is used to construct an expected value equation characterizing the overall output level of the permanent magnet wind turbine based on the joint probability density function and the output power.
[0080] The verification scenario selection module 500 is used to solve the expected value equation and determine the candidate verification scenarios corresponding to the wind speed value and ambient temperature value that satisfy the expected value equation as the final short-circuit demagnetization verification scenarios.
[0081] This embodiment provides a system for determining short-circuit demagnetization verification scenarios for permanent magnet wind turbines. This system is used to implement the aforementioned method for determining short-circuit demagnetization verification scenarios for permanent magnet wind turbines. Therefore, the specific implementation of this system can be found in the embodiments section of the method for determining short-circuit demagnetization verification scenarios for permanent magnet wind turbines described above. For example, the joint probability density acquisition module 100, candidate scenario determination module 200, output power calculation module 300, expected value equation construction module 400, and verification scenario selection module 500 are respectively used to implement steps S1, S2, S3, S4, and S5 in the aforementioned method for determining short-circuit demagnetization verification scenarios for permanent magnet wind turbines. Therefore, the specific implementation can be referred to the descriptions of the corresponding embodiments. To avoid redundancy, further details are omitted here.
[0082] Example 3: This embodiment of the invention provides an electronic device, which includes a processor, a memory, and a bus system. The processor and the memory are connected through the bus system. The memory is used to store instructions, and the processor is used to execute the instructions stored in the memory to realize the above-mentioned method for determining the short-circuit demagnetization verification scenario of a permanent magnet wind turbine.
[0083] Example 4: This embodiment of the invention provides a computer storage medium storing a computer software product. The computer software product includes several instructions to cause a computer device to execute the above-described method for determining the short-circuit demagnetization verification scenario of a permanent magnet wind turbine.
[0084] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.
[0085] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.
[0086] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The functions specified in one or more boxes. These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable apparatus for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.
[0087] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.
Claims
1. A method for determining the short-circuit demagnetization verification scenario of a permanent magnet wind turbine, characterized in that, include: Obtain the joint probability density function of wind speed and ambient temperature for the target wind field; Based on the joint probability density function, multiple candidate verification scenarios are determined, and each candidate verification scenario corresponds to a set of wind speed values and ambient temperature values. Calculate the output power of the permanent magnet wind turbine after a short-circuit fault occurs in each candidate verification scenario, specifically including: For each candidate verification scenario, the three-phase short-circuit process of the permanent magnet wind turbine under that scenario is simulated, and the degree of irreversible demagnetization of the permanent magnet caused by the short-circuit current is calculated. Based on the aforementioned degree of demagnetization, a model of a demagnetized permanent magnet wind turbine generator is established; Under the preset rated operating conditions, the rated current is passed into the demagnetized permanent magnet wind turbine model, and its output electromagnetic power and stator-side losses are calculated. Based on the electromagnetic power and stator-side losses, the output power of the permanent magnet wind turbine after short-circuit demagnetization in this candidate verification scenario is calculated. Based on the joint probability density function and the output power, an expected value equation is constructed to characterize the overall output level of the permanent magnet wind turbine. The expected value equation is the weighted sum of the output power corresponding to all candidate verification scenarios and their occurrence probabilities, which is equal to the output power corresponding to the finally determined verification scenario. The occurrence probability of each candidate verification scenario is determined by the joint probability density function. Solve the expected value equation, and determine the candidate verification scenarios corresponding to the wind speed and ambient temperature values that satisfy the expected value equation as the final short-circuit demagnetization verification scenarios.
2. The method for determining the short-circuit demagnetization verification scenario of a permanent magnet wind turbine according to claim 1, characterized in that, The acquisition of the joint probability density function of wind speed and ambient temperature of the target wind field specifically includes: Collect historical wind speed data and historical ambient temperature data for the target wind field; Determine the probability distribution models for wind speed and ambient temperature respectively; Based on the probability distribution model of wind speed and the probability distribution model of ambient temperature, and considering the correlation between wind speed and ambient temperature, the joint probability density function is constructed.
3. The method for determining the short-circuit demagnetization verification scenario of a permanent magnet wind turbine according to claim 1, characterized in that, The preset rated operating conditions specifically include: the preset maximum wind speed value and the preset maximum ambient temperature value.
4. The method for determining the short-circuit demagnetization verification scenario of a permanent magnet wind turbine according to claim 1, characterized in that, The degree of demagnetization is characterized by a percentage of torque loss, which is the ratio of the difference between the average electromagnetic torque before and after demagnetization under the same stator current to the average electromagnetic torque before demagnetization.
5. The method for determining the short-circuit demagnetization verification scenario of a permanent magnet wind turbine according to claim 1, characterized in that, The expected value equation is specifically expressed as follows: ； in, to for Output power corresponding to each candidate verification scenario to for The probability of occurrence of each candidate verification scenario For the final verification scenario The corresponding output power.
6. A system for determining short-circuit demagnetization verification scenarios for permanent magnet wind turbines, characterized in that, The system is used to implement the method for determining the short-circuit demagnetization verification scenario of the permanent magnet wind turbine as described in any one of claims 1 to 5, specifically including: The joint probability density acquisition module is used to obtain the joint probability density function of wind speed and ambient temperature of the target wind field. The candidate scene determination module is used to determine multiple candidate verification scenes based on the joint probability density function, and each candidate verification scene corresponds to a set of wind speed values and ambient temperature values. The output power calculation module is used to calculate the output power of the permanent magnet wind turbine after a short circuit fault occurs in each candidate verification scenario. The expected value equation construction module is used to construct an expected value equation characterizing the overall output level of the permanent magnet wind turbine based on the joint probability density function and the output power. The verification scenario selection module is used to solve the expected value equation and determine the candidate verification scenarios corresponding to the wind speed and ambient temperature values that satisfy the expected value equation as the final short-circuit demagnetization verification scenarios.
7. An electronic device, characterized in that, The electronic device includes a processor, a memory, and a bus system. The processor and the memory are connected through the bus system. The memory is used to store instructions, and the processor is used to execute the instructions stored in the memory to implement the method for determining the short-circuit demagnetization verification scenario of the permanent magnet wind turbine as described in any one of claims 1 to 5.
8. A computer storage medium, characterized in that, The computer storage medium stores a computer software product, which includes several instructions to cause a computer device to execute the method for determining the short-circuit demagnetization verification scenario of the permanent magnet wind turbine as described in any one of claims 1 to 5.