Offshore wind turbine operation mode switching control method and device

Abstract

This invention provides a method and apparatus for switching operating modes of offshore wind turbines, relating to the field of wind turbine control technology. The method includes: real-time acquisition of operating parameters and environmental parameters corresponding to key nodes of the turbine; construction of a turbine operating state topology dataset through spatiotemporal correlation coding to determine the environmental mutation coefficient and structural response index; calculation of a comprehensive threat index; triggering a mode switching signal when the threat index exceeds a preset threshold; setting a transition control phase between the power generation mode and the shutdown mode; determining the initial power decline rate through generator speed and DC bus voltage; calculating a yaw compensation term based on the wind direction change rate; correcting the power decline rate; achieving power ramp-down and active yaw control until shutdown; and continuously monitoring the environmental and structural status after stable shutdown. If the status returns to normal within multiple consecutive cycles, the power output is gradually restored to the rated value, achieving safe and efficient operating mode switching.

Description

Technical Field

[0001] This invention relates to the field of wind turbine control technology, specifically to a method and device for switching operating modes of offshore wind turbines. Background Technology

[0002] In the typhoon-prone waters of southeastern coastal areas, offshore wind turbines face severe challenges. Every summer, the region is frequently hit by strong typhoons with wind speeds exceeding 40 m / s, posing a significant threat to the safe operation of wind turbines. Currently, many offshore wind turbines employ a semi-direct-drive medium-speed transmission structure and are equipped with full-power converters and active yaw systems to improve power generation efficiency and adaptability. However, existing control strategies show significant shortcomings in handling emergency shutdowns during typhoons. Grid operators typically require turbines to perform emergency shutdowns before a typhoon arrives, but switching to shutdown mode too early inevitably leads to considerable economic losses for the generators, while switching too late may cause overvoltage on the converter's DC bus due to sudden turbulence, increasing the risk of equipment damage. This operational contradiction reflects the limitations of existing control strategies in dynamically responding to extreme weather conditions, failing to minimize power generation losses while ensuring safety.

[0003] Furthermore, determining the restart timing during the wind speed decline phase after a typhoon relies on simple wind speed thresholds, a method with significant uncertainties in practice. Traditional control strategies easily lead to frequent start-ups and shutdowns of the turbine under gusty conditions, increasing mechanical wear and the risk of failure, thus affecting the long-term stability and reliability of the turbine. The lack of real-time monitoring and dynamic assessment of sudden environmental changes prevents the turbine from flexibly responding to complex weather variations, impacting overall operating efficiency. To effectively address these issues, there is an urgent need for an intelligent control method that comprehensively considers environmental changes, operating status, and real-time data to achieve a smooth transition of wind turbines under extreme weather conditions, ensuring both safety and economic benefits.

[0004] The information disclosed in the background section is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a method and apparatus for switching operating modes of offshore wind turbines to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for switching operating modes of offshore wind turbines, comprising the following steps:

[0008] Step 1: Real-time acquisition of operating parameters and environmental parameters of different key nodes of the unit, and construction of unit operating status topology dataset through spatiotemporal correlation coding using node topology number as index; the operating parameters include generator speed, DC bus voltage, and three-dimensional nacelle vibration acceleration, and the environmental parameters include wind speed, wind direction, and turbulence intensity;

[0009] Step 2: Based on the unit operating status topology dataset, determine the environmental mutation coefficient and structural response index, calculate the comprehensive threat index based on the environmental mutation coefficient and structural response index, and trigger a mode switching signal when the comprehensive threat index exceeds the preset mutation threshold;

[0010] Step 3: Based on the mode switching signal, a transition control phase is inserted between the generation mode and the shutdown mode. The execution logic is as follows: First, the initial power reduction rate is determined based on the current generator speed and DC bus voltage. At the same time, the yaw compensation term is calculated according to the wind direction change rate. The yaw system is controlled to perform active offset. The initial power reduction rate is corrected using the yaw compensation term to obtain the tuned reduction rate. The converter is then controlled to perform power ramp-down at this rate until the shutdown state is reached.

[0011] Step 4: After the unit enters a stable shutdown state, continuously monitor the environmental mutation coefficient and structural response index: If the environmental mutation coefficient and structural response index return to the normal range within 3 consecutive monitoring cycles, start the soft start procedure, first restore the grid connection function of the converter, and then gradually increase the power output to the rated value.

[0012] Furthermore, the specific execution process of step 1 is as follows:

[0013] The key nodes include the generator bearing housing, the converter DC bus terminal, and the nacelle-tower connection flange of the unit. Sensing nodes are installed at each key node. Generator speed data is collected at the generator bearing housing, DC bus voltage data is collected at the converter DC bus terminal, and three-dimensional nacelle vibration acceleration data is collected at the nacelle-tower connection flange, serving as the unit's operating parameters. Simultaneously, real-time wind speed, wind direction, and turbulence intensity are acquired as environmental parameters through an anemometer and wind vane. Each sensing node is assigned a unique topology number containing a location code and a function identifier. After binding the operating parameters to their topology numbers and timestamps, data alignment and verification are performed according to preset spatiotemporal association rules to construct a unit operating status topology dataset containing operating parameter values, spatial location, and time information.

[0014] The turbulence intensity is defined as the ratio of the standard deviation of the wind speed at the top of the nacelle within the current 30 seconds to the average wind speed within the most recent 10 minutes, which is used to quantify the instability of wind energy input.

[0015] Furthermore, based on the aforementioned unit operating status topology dataset, the environmental mutation coefficient and structural response index are determined using the following formulas:

[0016] ;

[0017] In the formula, This is the environmental abrupt change coefficient, used to reflect the drastic nature of changes in wind speed and direction. The instantaneous wind speed at the current moment. The average wind speed over the most recent 10 minutes. The rate of change of wind direction at the current moment. It is a wind direction sensitivity coefficient, and ; The structural response index is used to characterize abnormal states of the unit's mechanical and electrical systems. , and These represent the three-dimensional nacelle vibration accelerations along the main shaft, lateral direction, and vertical direction of the wind turbine at the current moment, respectively. , and These represent the vibration acceleration thresholds along the main shaft direction, the lateral direction, and the vertical direction of the wind turbine, respectively. The DC bus voltage at the current moment. This is the rated DC voltage. It is a voltage influence factor, and ; The generator speed at the current moment. This is the reference speed under the current operating conditions. It is the speed sensitivity coefficient, and ;

[0018] The wind direction change rate is determined based on the wind direction data of the current moment and the previous moment, using the following formula:

[0019] ;

[0020] In the formula, For the correction function, This refers to the wind direction data at the current moment. Refers to the wind direction data at the previous moment. This represents the time interval between the current moment and the previous moment. It is a symbolic function.

[0021] Furthermore, the comprehensive threat index is calculated based on the environmental abrupt change coefficient and the structural response index, using the following formula:

[0022] ;

[0023] In the formula, The comprehensive threat index is used to assess the overall risk level currently faced by the unit. The environmental mutation coefficient, The structural response index. finger take and The maximum value in is used to make Always fall Within the range;

[0024] And when the comprehensive threat index When this occurs, a mode switching signal is triggered;

[0025] in, The preset mutation threshold is determined based on the unit type and typhoon level.

[0026] Furthermore, based on the current generator speed and DC bus voltage, the initial power reduction rate is determined using a lookup table method:

[0027] ;

[0028] In the formula, The initial power decrease rate, The rated power of the unit, The DC bus voltage at the current moment. The rated DC voltage, The generator speed at the current moment. This is the reference speed under the current operating conditions;

[0029] Calculate the yaw compensation angle based on the wind direction change rate. :

[0030] ;

[0031] In the formula, For yaw compensation angle, The rate of change of wind direction at the current moment. This refers to the yaw system response time.

[0032] The initial power drop rate is corrected using the yaw compensation angle to obtain the tuned power drop rate, based on the following formula:

[0033] ;

[0034] In the formula, To tune the descent rate;

[0035] Control converter according to The power ramp is reduced while the yaw system is controlled. The angle shifts, and the direction of the shift is opposite to the direction of the wind change.

[0036] Furthermore, the specific execution process of step 4 is as follows: after the unit enters a stable shutdown state, the environmental mutation coefficient and structural response index are continuously monitored. If the coefficient and index are both lower than their respective safety thresholds within three consecutive monitoring cycles, a phased soft start procedure is initiated: first, the electrical connection between the converter and the grid is restored and zero power output is maintained. After the electrical parameters stabilize, the power output is gradually increased at a preset rate. At the same time, the unit status parameters are monitored in real time during the power increase process. If an abnormality is detected, the power increase process is paused and the current operating state is maintained until the unit status stabilizes again and the power is increased again, ultimately restoring the unit to rated power operation.

[0037] The present invention also provides an operating mode switching control device for offshore wind turbines, wherein the operating mode switching control device for offshore wind turbines is used to execute the above-mentioned operating mode switching control method for offshore wind turbines, including:

[0038] The multi-source data acquisition module is used to collect the operating parameters and environmental parameters of different key nodes of the unit in real time, and construct the unit operating status topology dataset by using the node topology number as an index and spatiotemporal correlation coding; the operating parameters include generator speed, DC bus voltage, and three-dimensional nacelle vibration acceleration, and the environmental parameters include wind speed, wind direction, and turbulence intensity.

[0039] The threat assessment and decision-making module is used to determine the environmental mutation coefficient and structural response index based on the unit's operating status topology dataset, calculate the comprehensive threat index based on the environmental mutation coefficient and structural response index, and trigger a mode switching signal when the comprehensive threat index exceeds a preset mutation threshold.

[0040] The collaborative transition control module is used to insert a transition control phase between the power generation mode and the shutdown mode based on the mode switching signal. Its execution logic is as follows: First, the initial power reduction rate is determined based on the current generator speed and DC bus voltage. At the same time, the yaw compensation term is calculated according to the wind direction change rate. The yaw system is controlled to perform active offset. The initial power reduction rate is corrected using the yaw compensation term to obtain the tuned reduction rate. The converter is then controlled to perform power ramp-down at this rate until the shutdown state is reached.

[0041] The safe reconnection module is used to continuously monitor the environmental mutation coefficient and structural response index after the unit enters a stable shutdown state. If the environmental mutation coefficient and structural response index return to the normal range within three consecutive monitoring cycles, the soft start program is started to restore the grid connection function of the converter first, and then gradually increase the power output to the rated value.

[0042] Compared with the prior art, the beneficial effects of the present invention are:

[0043] This invention significantly improves the safety and reliability of turbine operation under typhoon conditions through multi-dimensional state monitoring and intelligent decision-making mechanisms. The innovative solution integrates environmental abrupt changes with structural dynamic response for evaluation, enabling more precise timing of mode switching and avoiding power loss due to premature shutdown and equipment risks caused by delayed response. During the transition control phase, the coordinated operation of power regulation and the yaw system effectively suppresses electrical shocks and mechanical vibrations during mode switching, ensuring a smooth shutdown of the turbine. Simultaneously, the intelligent reconnection strategy based on multi-parameter verification overcomes the shortcomings of traditional methods in frequent start-stop operations under gust conditions, enabling the turbine to safely and stably resume power generation. The overall solution optimizes the turbine control strategy throughout the entire typhoon process while ensuring equipment safety, providing an innovative solution for the reliable operation of offshore wind power under extreme weather conditions. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the overall method flow of the present invention;

[0045] Figure 2 This is a schematic diagram of the overall device module of the present invention;

[0046] Figure 3 , Figure 4 The figures are 3D scatter plots and 3D bar charts for the environmental mutation coefficient, structural response index, and comprehensive threat index, respectively. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0048] It should be noted that, unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0049] Example:

[0050] Please see Figure 1 The present invention provides a technical solution:

[0051] The specific steps of the operation mode switching control method for offshore wind turbines include:

[0052] Step 1: Real-time acquisition of operating parameters and environmental parameters of different key nodes of the unit, and construction of unit operating status topology dataset through spatiotemporal correlation coding using node topology number as index; the operating parameters include generator speed, DC bus voltage, and three-dimensional nacelle vibration acceleration, and the environmental parameters include wind speed, wind direction, and turbulence intensity;

[0053] In this embodiment, the specific execution process of step 1 is as follows:

[0054] The key nodes include the generator bearing housing, the converter DC bus terminal, and the nacelle-tower connection flange of the unit. Sensing nodes are installed at each key node. Generator speed data is collected at the generator bearing housing, DC bus voltage data is collected at the converter DC bus terminal, and three-dimensional nacelle vibration acceleration data is collected at the nacelle-tower connection flange, serving as the unit's operating parameters. Simultaneously, real-time wind speed, wind direction, and turbulence intensity are acquired as environmental parameters through an anemometer and wind vane. Each sensing node is assigned a unique topology number containing a location code and a function identifier. After binding the operating parameters to their topology numbers and timestamps, data alignment and verification are performed according to preset spatiotemporal association rules to construct a unit operating status topology dataset containing operating parameter values, spatial location, and time information.

[0055] The turbulence intensity is defined as the ratio of the standard deviation of the wind speed at the top of the nacelle within the current 30 seconds to the average wind speed within the most recent 10 minutes, which is used to quantify the instability of wind energy input.

[0056] Step 1 involves real-time acquisition of operating and environmental parameters from different key nodes of the unit, and the construction of an operating status topology dataset indexed by node topology numbers. This achieves effective organization and management of multi-node data. Spatiotemporal correlation coding is used to align the acquired data in time, bind its spatial location, and perform anomaly checks, ensuring data integrity and consistency and providing a reliable foundation for subsequent analysis. Compared to traditional methods, this step can more accurately capture the dynamic changes in the unit's operating status and the impact of the environment on the unit, laying the foundation for faster and more accurate mode switching decisions.

[0057] Compared with existing technologies, the benefits of step 1 are reflected in the following aspects: First, by comprehensively collecting key node operating parameters and quantitatively monitoring environmental parameters, the operating status of the unit can be reflected more accurately; second, by adopting spatiotemporal correlation rules to achieve unified alignment of multi-node data and handle outliers, the reliability and availability of data are improved; third, by introducing spatial location and temporal information into the dataset to topologically organize the data, more complex state modeling and subsequent analysis are supported. Overall, step 1 significantly improves the accuracy and real-time performance of wind turbine operating status perception.

[0058] In this invention, step 1, as a fundamental step, plays a crucial role in promoting the overall solution. By constructing an operational state topology dataset, it not only provides high-quality data support for the accurate calculation of environmental mutation coefficients and structural response indices, but also enables dynamic coordination among multiple nodes and parameters, ensuring that the triggering conditions for mode switching can be evaluated based on the complete state. This step also provides reliable input parameters for the transition control phase, enhancing the safety and accuracy of mode switching, thereby guaranteeing the stable operation and efficient control of the generator set in complex environments.

[0059] Step 2: Based on the unit operating status topology dataset, determine the environmental mutation coefficient and structural response index, calculate the comprehensive threat index based on the environmental mutation coefficient and structural response index, and trigger a mode switching signal when the comprehensive threat index exceeds the preset mutation threshold;

[0060] In this embodiment, the environmental mutation coefficient and structural response index are determined based on the unit operating status topology dataset, using the following formulas:

[0061] ;

[0062] In the formula, This is the environmental abrupt change coefficient, used to reflect the drastic nature of changes in wind speed and direction. The instantaneous wind speed at the current moment. The average wind speed over the most recent 10 minutes. The rate of change of wind direction at the current moment. It is a wind direction sensitivity coefficient, and ; The structural response index is used to characterize abnormal states of the unit's mechanical and electrical systems. , and These represent the three-dimensional nacelle vibration accelerations along the main shaft, lateral direction, and vertical direction of the wind turbine at the current moment, respectively. , and These represent the vibration acceleration thresholds along the main shaft direction, the lateral direction, and the vertical direction of the wind turbine, respectively. The DC bus voltage at the current moment. This is the rated DC voltage. It is a voltage influence factor, and ; The generator speed at the current moment. This is the reference speed under the current operating conditions. It is the speed sensitivity coefficient, and ;

[0063] This formula quantifies the relative intensity of wind speed fluctuations by dividing the product of turbulence intensity and instantaneous wind speed by the average wind speed. It also reflects the impact of sudden wind direction changes by combining the product of the wind direction sensitivity coefficient and the absolute value of the wind direction change rate. Formally, this achieves an organic integration of wind speed and wind direction, two types of environmental parameters. All parameters are expressed as dimensionless or physical quantity ratios to ensure that environmental changes in different dimensions can be directly superimposed and calculated. Furthermore, positive coefficients are used... By adjusting the weight of wind direction, the formula can reflect both the overall stability of wind energy input and the threat of drastic wind direction changes, which is in line with the comprehensive assessment logic of environmental change risk. The calculation results can be directly used for subsequent threat index determination.

[0064] The formula for calculating the environmental mutation coefficient has the environmental mutation coefficient as its dependent variable. This indicator reflects the severity of changes in wind speed and direction, and is a comprehensive quantitative measure of the stability of wind energy input and the risk of sudden wind direction changes. Its technical advantage lies in its ability to rapidly identify extreme wind conditions by integrating the ratio of turbulence intensity to instantaneous wind speed and the rate of change of wind direction. This provides an environmental basis for mode switching and avoids frequent unit start-ups and shutdowns caused by misjudgments based on a single parameter. This item reflects the amplitude of wind speed fluctuations; the larger the ratio, the more drastic the sudden change in wind speed. The item directly reflects the speed of wind direction change. Used to amplify sudden changes in wind direction The impact of drastic wind changes ensures that when wind direction changes drastically... Significantly increased, therefore, and , They show a positive correlation.

[0065] For the formula of structural response index, the dependent variable is the structural response index. This is used to characterize the abnormal state of the unit's mechanical and electrical systems, meaning the degree to which combined vibration, voltage, and speed deviate from the normal range. The technical advantage lies in comprehensively reflecting abnormalities in the unit's structural stress and electrical performance through multi-dimensional parameter fusion, avoiding missed detections when a single parameter exceeds a threshold, and providing a basis for equipment safety judgments during mode switching. Vibration acceleration ratio item Reflecting the degree of structural vibration exceeding limits, voltage and speed deviations , Reflects the stability of the electrical system , Used to adjust two types of deviations The influence weight.

[0066] This formula uses the square root of the sum of the squares of the three-dimensional vibration acceleration ratios to represent the overall degree of exceeding limits of structural vibration. It also incorporates the relative values ​​of voltage and speed deviations to reflect electrical system anomalies, formally achieving cross-domain integration of mechanical and electrical parameters. All deviation terms are expressed as relative values, eliminating differences between different physical dimensions, and using positive coefficients... , By flexibly adjusting the weights of the two types of deviations, the formula can comprehensively cover the key state parameters of the unit, while highlighting key concerns based on equipment characteristics. The calculation results can objectively reflect the overall abnormality of the unit and meet the quantitative requirements of structural safety assessment.

[0067] The wind direction change rate is determined based on the wind direction data of the current moment and the previous moment, using the following formula:

[0068] ;

[0069] In the formula, For the correction function, This refers to the wind direction data at the current moment. Refers to the wind direction data at the previous moment. This represents the time interval between the current moment and the previous moment. This is a sign function used to determine the direction of change between the current wind direction and the previous wind direction. When the wind direction changes from... arrive When changing clockwise, When the wind direction changes arrive When it changes counterclockwise, .

[0070] The comprehensive threat index is calculated based on the environmental abrupt change coefficient and the structural response index, using the following formula:

[0071] ;

[0072] In the formula, The comprehensive threat index is used to assess the overall risk level currently faced by the unit. The environmental mutation coefficient, The structural response index. finger take and The maximum value in is used to make Always fall Within the range;

[0073] And when the comprehensive threat index When this occurs, a mode switching signal is triggered;

[0074] in, The preset mutation threshold is determined based on the unit type and typhoon level.

[0075] Dependent variable This is a comprehensive threat index used to assess the overall risk level currently faced by wind turbine units. It means that it comprehensively considers the environmental abrupt change coefficient and the structural response index, and limits the risk assessment results to a range through normalization. Within a given range, the results are made intuitive and comparable. When the comprehensive threat index... Exceeding the set threshold In this case, a mode switching signal is triggered to protect the unit's safety. Its technical effectiveness lies in its ability to effectively combine the dynamic characteristics of environmental changes and unit response, promptly assess and warn of overall risks in the unit's operating status, and provide guidance for the safe and stable operation of wind turbines; among other things, a preset sudden change threshold is included. The setting is determined based on a comprehensive assessment of the unit type, design safety margin, and typhoon level of the area.

[0076] In the formula, the independent variables, the environmental abrupt change coefficient and the structural response index, reflect the corresponding states of the wind turbine's operating environment and the turbine's own response. Together, they determine the dependent variable... The magnitude of the coefficient of variation. Specifically, a larger environmental abrupt change coefficient indicates that drastic changes in the external environment pose a threat to the unit's operation; a larger structural response index reflects potential significant anomalies in the unit's mechanical or electrical systems. Multiplying these two values ​​and then normalizing them comprehensively reflects the combined impact of the external environment and the unit's response on the overall risk. The relationship between the independent and dependent variables indicates that... The change is a combined result of changes in the environmental mutation coefficient and the structural response index. The larger the environmental mutation coefficient and the structural response index, the higher the overall risk of the system. and , Both show a positive correlation; that is, when the environmental abrupt change coefficient or the structural response index increases, the comprehensive threat index increases. This will also increase, indicating that the current risk level of the unit has risen.

[0077] Table 1: Comprehensive Threat Index Statistics

[0078]

[0079] Please see Figures 3-4 Analysis of the above 15 sets of data shows that the comprehensive threat index in this plan... It can effectively reflect the coupling effect between environmental abrupt changes and structural responses. Data analysis shows that the comprehensive threat index... It exhibits a unique "coupling amplification-normalization constraint" characteristic: when the environmental abrupt change coefficient... With structural response index When the increase is synchronous, such as in groups 3, 7, and 12, The value will quickly approach 1, accurately reflecting the combined effect of the double risk; while when and When the difference is significant, such as in group 5 , , The value will converge toward a smaller value, but through The product term retains the synergistic effect of both. This design avoids misjudgment caused by a sudden change in a single parameter, and also... The normalization process ensures the stability of the output value range, and this characteristic ensures the stability and reliability of risk assessment.

[0080] From the perspective of data distribution, The value exhibits a clear ability to differentiate operating conditions: in and Under normal operating conditions with relatively low loads, such as groups 1, 4, and 9, Maintain below 0.3; when any indicator enters the warning range, such as groups 2, 6, and 11, The value correspondingly rises to the 0.3-0.6 range; and under extreme working conditions with double risks, such as groups 3, 7, and 12, The value will quickly climb to above 0.6. This nonlinear response characteristic enables this scheme to not only capture the threat of a single risk source in a timely manner, but also accurately identify complex risks, and has better risk identification accuracy and anti-interference ability than the traditional linear weighting method.

[0081] Step 2 calculates the environmental mutation coefficient and structural response index based on the operating status topology dataset to comprehensively assess the impact of unit operating status and external environmental changes on unit stability. Furthermore, it calculates the comprehensive threat index as the core criterion for triggering mode switching, thus improving the scientific rigor and accuracy of mode switching. Compared to mode switching methods based on single monitoring parameters or experience, Step 2 enables multi-dimensional and multi-parameter comprehensive analysis, fully capturing the coupling relationship between environmental changes and internal unit responses, providing a quantitative and accurate assessment basis for mode switching.

[0082] Compared with existing technologies, the beneficial effects of step 2 are as follows: First, by introducing the environmental mutation coefficient, the degree of disturbance to unit operation by complex environments can be effectively quantified; second, by calculating the structural response index, the health status of the unit's mechanical and electrical systems can be accurately reflected; and third, by utilizing the comprehensive threat index, data from different dimensions are normalized and processed to form a unified mode switching criterion, making mode switching more sensitive and reliable. Overall, step 2 significantly improves the accuracy and timeliness of mode switching signal triggering.

[0083] In this invention, step 2 is a crucial step in realizing the core logic of mode switching. By calculating the environmental mutation coefficient and structural response index, the dynamic changes in the external environment and unit response can be captured in real time, providing a scientific basis for triggering the mode switching signal. Simultaneously, the introduction of a comprehensive threat index effectively solves the quantification problem of complex coupling relationships among multiple parameters, making mode switching more intelligent. This step provides accurate triggering conditions for the subsequent transition control phase, ensuring the timeliness and safety of mode switching, thereby guaranteeing the stable operation of the unit in harsh environments.

[0084] Step 3: Based on the mode switching signal, a transition control phase is inserted between the generation mode and the shutdown mode. The execution logic is as follows: First, the initial power reduction rate is determined based on the current generator speed and DC bus voltage. At the same time, the yaw compensation term is calculated according to the wind direction change rate. The yaw system is controlled to perform active offset. The initial power reduction rate is corrected using the yaw compensation term to obtain the tuned reduction rate. The converter is then controlled to perform power ramp-down at this rate until the shutdown state is reached.

[0085] In this embodiment, the initial power reduction rate is determined by a lookup table method based on the current generator speed and DC bus voltage:

[0086] ;

[0087] In the formula, The initial power decrease rate, The rated power of the unit, The DC bus voltage at the current moment. The rated DC voltage, The generator speed at the current moment. This is the reference speed under the current operating conditions;

[0088] The formula defines the initial power reduction rate in segments based on the deviation between generator speed and DC bus voltage, and correlates it with the unit's rated power. This form is reasonable and physically meaningful. The formula sets refined power reduction rates according to different conditions: when the speed significantly exceeds the reference value and the voltage deviation is large, a higher rate is selected for rapid response and unit protection; when the speed or voltage deviation is small, the power reduction rate is reduced to a lower rate. To reduce unnecessary power regulation; under other operating conditions, set the minimum descent rate. This maintains the basic protection mechanism. The segmented mode dynamically adjusts the power reduction rate based on the risk level of the unit's operating status, providing a clear framework that ensures both unit safety and operational efficiency.

[0089] Calculate the yaw compensation angle based on the wind direction change rate. :

[0090] ;

[0091] In the formula, For yaw compensation angle, The rate of change of wind direction at the current moment. This refers to the yaw system response time.

[0092] Dependent variable This is the yaw compensation angle, used to adjust the yaw system of a wind turbine to adapt to changes in wind direction. Its meaning is based on the rate of change of wind direction. and yaw system response time The required angle compensation is dynamically calculated, and its maximum value is limited to 0. This is to avoid excessive yaw causing damage to the system. The technical advantage lies in its ability to quickly respond to drastic changes in wind direction, improving wind capture efficiency, while balancing response speed and system lifespan by limiting the compensation angle. The rate of change of wind direction directly determines the urgency of yaw adjustments; the faster the change, the larger the required compensation angle. The response time of the yaw system determines the responsiveness of the yaw action; the longer the response time, the larger the required compensation angle. Dependent Variable It is a combined result of these two factors, reflecting the specific yaw requirements of the system under different wind direction changes.

[0093] The initial power drop rate is corrected using the yaw compensation angle to obtain the tuned power drop rate, based on the following formula:

[0094] ;

[0095] In the formula, To tune the descent rate;

[0096] Control converter according to The power ramp is reduced while the yaw system is controlled. The angle shifts, and the direction of the shift is opposite to the direction of the wind change.

[0097] Dependent variable The tuning descent rate reflects the consideration of yaw compensation angle. Then, the initial power decrease rate The correction result means that by introducing a yaw compensation angle, the power reduction rate is dynamically adjusted, allowing the power reduction to more accurately adapt to changes in wind direction and operating conditions faced by the unit. The technical effects are as follows: when the yaw angle is large, the power reduction rate is moderately reduced, avoiding the impact of over-response on unit operation; while when the yaw angle is small, the adjustment range of the power reduction rate is reduced, ensuring the unit can quickly respond to abnormal situations, thereby effectively improving operational stability and efficiency.

[0098] Yaw state directly reflects the wind turbine's ability to track wind direction and the severity of wind direction changes. When the yaw compensation angle increases, it means the wind direction change is significant or the turbine is not perfectly aligned with the wind. In this case, adjusting the power reduction rate using a formula reduces the magnitude of power loss, preventing excessively rapid power loss due to directional deviation or wind fluctuations. Independent variable The introduction of makes the rate of descent It comprehensively considers the impact of yaw angle on power regulation, reflecting the dynamic characteristics of wind turbine operation. Dependent variable With independent variable There is a negative correlation. A larger yaw compensation angle indicates a more drastic change in wind direction, resulting in a correspondingly smaller rate of power reduction, meaning a slower rate of power decrease to avoid excessive power adjustment caused by drastic wind direction fluctuations; conversely, when... When smaller, the tuning descent rate Closer to the initial value This maintains a high response speed, thus balancing the efficiency of power regulation with the stability of system protection. In the formula... The design reasonably limits the adjustment range of the tuning descent rate, ensuring the appropriateness and safety of the system response.

[0099] Step 3 introduces a transition control phase to achieve a smooth transition between power generation and shutdown modes, avoiding the mechanical shocks or electrical system instability that might result from direct switching of wind turbine units. By determining the initial power reduction rate based on generator speed and DC bus voltage, and dynamically calculating the yaw compensation term in conjunction with wind direction changes, the power reduction rate is tuned and optimized. This achieves a synergistic effect between power ramp-down and active yaw control, resulting in smoother unit operation. Simultaneously, this step addresses the issue of delayed unit response under rapid changes in wind speed and direction, enhancing the unit's adaptability to complex environments.

[0100] Compared with existing technologies, the beneficial effects of step 3 are as follows: First, by introducing a tuned descent rate design, the power descent rate can be precisely adjusted according to the real-time operating status, reducing the impact of unit load changes on the power grid; second, through dynamic calculation of the yaw compensation angle and active yaw control, the unit can quickly adapt to changes in wind direction, reducing the loss of wind energy utilization efficiency; third, through the linkage control of power and yaw, the load fluctuations of the mechanical structure and electrical system are minimized, thereby extending the service life of key components. Overall, step 3 greatly improves the safety and stability of the mode switching process.

[0101] In this invention, step 3, as the core execution link of the operating mode switching, plays a crucial role in promoting the overall solution. By designing a transition control stage, the problem of drastic fluctuations that may occur during direct switching is solved, effectively ensuring the continuity and safety of unit operation. Simultaneously, this step combines power control and yaw control, fully considering the dynamic changes in environmental parameters and the real-time response of the unit's operating status, making the mode switching process smoother and more intelligent. Ultimately, this step provides technical support for the efficient switching of the unit from generation mode to shutdown mode, improving the applicability and reliability of the solution.

[0102] Step 4: After the unit enters a stable shutdown state, continuously monitor the environmental mutation coefficient and structural response index: If the environmental mutation coefficient and structural response index return to the normal range within 3 consecutive monitoring cycles, start the soft start program, first restore the grid connection function of the converter, and then gradually increase the power output to the rated value.

[0103] In this embodiment, the specific execution process of step 4 is as follows: After the unit enters a stable shutdown state, the environmental mutation coefficient and structural response index are continuously monitored. If the coefficient and index are both lower than their respective safety thresholds within three consecutive monitoring cycles, a phased soft start procedure is initiated: First, the electrical connection between the converter and the grid is restored and zero power output is maintained. After the electrical parameters stabilize, the power output is gradually increased at a preset rate. At the same time, the unit status parameters are monitored in real time during the power increase process. If an abnormality is detected, the power increase process is paused and the current operating state is maintained until the unit status stabilizes again and the power is increased again, so that the unit can finally be restored to rated power operation.

[0104] The monitoring cycle is set to 5-10 minutes, with the specific duration dynamically adjusted based on the unit's rated power and the intensity of turbulence in the surrounding sea area: the higher the rated power and the stronger the turbulence, the shorter the cycle should be. This setting can accurately determine the stability of the environment and the unit's status, while avoiding false starts due to an excessively short cycle or power generation losses due to an excessively long cycle.

[0105] Once the unit enters a stable shutdown state, the control system activates a continuous monitoring mechanism, tracking the environmental change coefficient in real time with a monitoring cycle of 5-10 minutes. and structural response index The changes. If within three consecutive monitoring periods, It is consistently below the environmental safety threshold, and If the voltage remains below the structural safety threshold, the external environment and unit status are deemed to meet the restart conditions, and a phased soft-start procedure is initiated: First, the converter is controlled to re-establish its electrical connection with the grid, maintaining a zero-power output state while continuously monitoring electrical parameters such as grid voltage, frequency, and converter DC-side voltage. The restart process continues until the fluctuations of all indicators are less than [a certain value]. The rated value is maintained for more than 30 seconds; the second step is to press... The power output is gradually increased at a preset rate of twice the rated power per minute. During the power increase process, status parameters such as generator speed, three-dimensional nacelle vibration acceleration, and DC bus voltage are collected simultaneously. If any parameter exceeds the preset safety range, the power increase is immediately stopped and the current output status is maintained until the parameter returns to normal and stabilizes for 1 minute. Then, the power is increased at the original rate, so that the unit can smoothly transition to the rated power operation state.

[0106] Step 4, through continuous monitoring of the environmental mutation coefficient and structural response index, enables dynamic assessment of the external environment and operating status during unit shutdown. Once conditions return to normal, a phased soft-start procedure is employed to gradually restore the unit's operating status. This phased recovery method avoids the mechanical shock and electrical system instability that could result from a direct, rapid start-up from a shutdown state, ensuring a smooth and safe startup process. Simultaneously, real-time monitoring and anomaly detection mechanisms enhance the adaptability and robustness of the soft-start process.

[0107] Compared with existing technologies, the benefits of step 4 are reflected in the following aspects: First, through multi-cycle verification of safety thresholds, the possibility of frequent switching due to short-term environmental fluctuations is reduced, improving the stability of mode switching; second, the phased soft-start procedure effectively reduces the stress burden on electrical and mechanical systems, extending the service life of key components; and third, through real-time monitoring and abnormal pause mechanisms during the power increase process, the safety and reliability of the unit are further guaranteed. Overall, this step significantly optimizes the recovery process after shutdown, making the unit operation more stable and efficient.

[0108] In this invention, step 4 is a crucial step in the unit's recovery from shutdown mode to power generation mode, playing a significant role in facilitating the overall solution. Continuous monitoring of the environment and unit status ensures the scientific and safe start-up process; a phased soft-start procedure smoothly increases the unit's power output, avoiding potential shocks and malfunctions during mode switching. This step, working in conjunction with previous steps, constructs a complete closed-loop control mechanism for mode switching, significantly improving the applicability and reliability of the solution in complex marine environments.

[0109] Please see Figure 2 The offshore wind turbine operating mode switching control device includes:

[0110] The multi-source data acquisition module is used to collect the operating parameters and environmental parameters of different key nodes of the unit in real time, and construct the unit operating status topology dataset by using the node topology number as an index and spatiotemporal correlation coding; the operating parameters include generator speed, DC bus voltage, and three-dimensional nacelle vibration acceleration, and the environmental parameters include wind speed, wind direction, and turbulence intensity.

[0111] The threat assessment and decision-making module is used to determine the environmental mutation coefficient and structural response index based on the unit's operating status topology dataset, calculate the comprehensive threat index based on the environmental mutation coefficient and structural response index, and trigger a mode switching signal when the comprehensive threat index exceeds a preset mutation threshold.

[0112] The collaborative transition control module is used to insert a transition control phase between the power generation mode and the shutdown mode based on the mode switching signal. Its execution logic is as follows: First, the initial power reduction rate is determined based on the current generator speed and DC bus voltage. At the same time, the yaw compensation term is calculated according to the wind direction change rate. The yaw system is controlled to perform active offset. The initial power reduction rate is corrected using the yaw compensation term to obtain the tuned reduction rate. The converter is then controlled to perform power ramp-down at this rate until the shutdown state is reached.

[0113] The safe reconnection module is used to continuously monitor the environmental mutation coefficient and structural response index after the unit enters a stable shutdown state. If the environmental mutation coefficient and structural response index return to the normal range within three consecutive monitoring cycles, the soft start program is started to restore the grid connection function of the converter first, and then gradually increase the power output to the rated value.

[0114] The above formulas are all dimensionless calculations. The formulas are derived from software simulations based on a large amount of collected data to obtain the most recent real-world results. The preset parameters in the formulas are set by those skilled in the art according to the actual situation.

[0115] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented in software, the above embodiments can be implemented, in whole or in part, as a computer program product. Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution.

[0116] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0117] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A method for switching operating modes of offshore wind turbines, characterized in that, The specific steps include: Step 1: Real-time acquisition of operating parameters and environmental parameters of different key nodes of the unit, and construction of unit operating status topology dataset through spatiotemporal correlation coding using node topology number as index; the operating parameters include generator speed, DC bus voltage, and three-dimensional nacelle vibration acceleration, and the environmental parameters include wind speed, wind direction, and turbulence intensity; Step 2: Based on the unit operating status topology dataset, determine the environmental mutation coefficient and structural response index, calculate the comprehensive threat index based on the environmental mutation coefficient and structural response index, and trigger a mode switching signal when the comprehensive threat index exceeds the preset mutation threshold; Step 3: Based on the mode switching signal, a transition control phase is inserted between the generation mode and the shutdown mode. The execution logic is as follows: First, the initial power reduction rate is determined based on the current generator speed and DC bus voltage. At the same time, the yaw compensation term is calculated according to the wind direction change rate. The yaw system is controlled to perform active offset. The initial power reduction rate is corrected using the yaw compensation term to obtain the tuned reduction rate. The converter is then controlled to perform power ramp-down at this rate until the shutdown state is reached. Step 4: After the unit enters a stable shutdown state, continuously monitor the environmental mutation coefficient and structural response index: If the environmental mutation coefficient and structural response index return to the normal range within 3 consecutive monitoring cycles, start the soft start procedure, first restore the grid connection function of the converter, and then gradually increase the power output to the rated value.

2. The method for switching operating modes of offshore wind turbines according to claim 1, characterized in that: The specific execution process of step 1 is as follows: The key nodes include the generator bearing housing, the converter DC bus terminal, and the nacelle-tower connection flange of the unit. Sensing nodes are installed at each key node. Generator speed data is collected at the generator bearing housing, DC bus voltage data is collected at the converter DC bus terminal, and three-dimensional nacelle vibration acceleration data is collected at the nacelle-tower connection flange, serving as the unit's operating parameters. Simultaneously, real-time wind speed, wind direction, and turbulence intensity are acquired as environmental parameters through an anemometer and wind vane. Each sensing node is assigned a unique topology number containing a location code and a function identifier. After binding the operating parameters to their topology numbers and timestamps, data alignment and verification are performed according to preset spatiotemporal association rules to construct a unit operating status topology dataset containing operating parameter values, spatial location, and time information. The turbulence intensity is defined as the ratio of the standard deviation of the wind speed at the top of the nacelle within the current 30 seconds to the average wind speed within the most recent 10 minutes, which is used to quantify the instability of wind energy input.

3. The method for switching operating modes of offshore wind turbines according to claim 1, characterized in that: Based on the aforementioned unit operating status topology dataset, the environmental mutation coefficient and structural response index are determined using the following formulas: ； In the formula, This is the environmental abrupt change coefficient, used to reflect the drastic nature of changes in wind speed and direction. The instantaneous wind speed at the current moment. The average wind speed over the most recent 10 minutes. The rate of change of wind direction at the current moment. It is a wind direction sensitivity coefficient, and ; The structural response index is used to characterize abnormal states of the unit's mechanical and electrical systems. , and These represent the three-dimensional nacelle vibration accelerations along the main shaft, lateral direction, and vertical direction of the wind turbine at the current moment, respectively. , and These represent the vibration acceleration thresholds along the main shaft direction, the lateral direction, and the vertical direction of the wind turbine, respectively. The DC bus voltage at the current moment. This is the rated DC voltage. It is a voltage influence factor, and ; The generator speed at the current moment. This is the reference speed under the current operating conditions. It is the speed sensitivity coefficient, and ; The wind direction change rate is determined based on the wind direction data of the current moment and the previous moment, using the following formula: ； In the formula, For the correction function, This refers to the wind direction data at the current moment. Refers to the wind direction data at the previous moment. This represents the time interval between the current moment and the previous moment. It is a symbolic function.

4. The method for switching operating modes of offshore wind turbines according to claim 3, characterized in that: The comprehensive threat index is calculated based on the environmental abrupt change coefficient and the structural response index, using the following formula: ； In the formula, The comprehensive threat index is used to assess the overall risk level currently faced by the unit. The environmental mutation coefficient, The structural response index. finger take and The maximum value in is used to make Always fall Within the range; And when the comprehensive threat index When this occurs, a mode switching signal is triggered; in, The preset mutation threshold is determined based on the unit type and typhoon level.

5. The method for switching operating modes of offshore wind turbines according to claim 1, characterized in that: Based on the current generator speed and DC bus voltage, the initial power reduction rate is determined using a lookup table method: ； In the formula, The initial power decrease rate, The rated power of the unit, The DC bus voltage at the current moment. The rated DC voltage, The generator speed at the current moment. This is the reference speed under the current operating conditions; Calculate the yaw compensation angle based on the wind direction change rate. : ； In the formula, For yaw compensation angle, The rate of change of wind direction at the current moment. This refers to the yaw system response time. The initial power drop rate is corrected using the yaw compensation angle to obtain the tuned power drop rate, based on the following formula: ； In the formula, To tune the descent rate; Control converter according to The power ramp is reduced while the yaw system is controlled. The angle shifts, and the direction of the shift is opposite to the direction of the wind change.

6. The method for switching operating modes of offshore wind turbines according to claim 1, characterized in that: The specific execution process of step 4 is as follows: After the unit enters a stable shutdown state, the environmental mutation coefficient and structural response index are continuously monitored. If the coefficient and index are both lower than their respective safety thresholds within three consecutive monitoring cycles, a phased soft start procedure is initiated: First, the electrical connection between the converter and the grid is restored and zero power output is maintained. After the electrical parameters stabilize, the power output is gradually increased at a preset rate. At the same time, the unit status parameters are monitored in real time during the power increase process. If an abnormality is detected, the power increase process is paused and the current operating state is maintained until the unit status stabilizes again and the power is increased again, so that the unit can finally be restored to rated power operation.

7. An operating mode switching control device for offshore wind turbines, characterized in that: The aforementioned offshore wind turbine operation mode switching control device is used to execute the offshore wind turbine operation mode switching control method according to any one of claims 1-6, comprising: The multi-source data acquisition module is used to collect the operating parameters and environmental parameters of different key nodes of the unit in real time, and construct the unit operating status topology dataset by using the node topology number as an index and spatiotemporal correlation coding; the operating parameters include generator speed, DC bus voltage, and three-dimensional nacelle vibration acceleration, and the environmental parameters include wind speed, wind direction, and turbulence intensity. The threat assessment and decision-making module is used to determine the environmental mutation coefficient and structural response index based on the unit's operating status topology dataset, calculate the comprehensive threat index based on the environmental mutation coefficient and structural response index, and trigger a mode switching signal when the comprehensive threat index exceeds a preset mutation threshold. The collaborative transition control module is used to insert a transition control phase between the power generation mode and the shutdown mode based on the mode switching signal. Its execution logic is as follows: First, the initial power reduction rate is determined based on the current generator speed and DC bus voltage. At the same time, the yaw compensation term is calculated according to the wind direction change rate. The yaw system is controlled to perform active offset. The initial power reduction rate is corrected using the yaw compensation term to obtain the tuned reduction rate. The converter is then controlled to perform power ramp-down at this rate until the shutdown state is reached. The safe reconnection module is used to continuously monitor the environmental mutation coefficient and structural response index after the unit enters a stable shutdown state. If the environmental mutation coefficient and structural response index return to the normal range within three consecutive monitoring cycles, the soft start program is started to restore the grid connection function of the converter first, and then gradually increase the power output to the rated value.

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