Yaw system limit load control method and system under fan single blade jamming working condition

Abstract

The application discloses a yaw system limit load control method and system under a single-blade jammed condition of a wind turbine, which needs to judge whether the wind turbine is in a single-blade jammed state, judges according to a pitch angle deviation value of any two blades, triggers a single-blade jammed fault when the deviation value is greater than a threshold value, and enters a shutdown mode; during the shutdown process, the measured blade root loads of the three blades are taken as inputs, a yaw system load is calculated through coordinate system conversion, a non-jammed blade is controlled in pitch according to the yaw system load, and a generator torque is controlled, so that the yaw system load of the wind turbine during the shutdown process meets design requirements. Through the pitch control of the non-jammed blade and the generator torque control, the yaw system load is reduced, the safety of the wind turbine is improved, and the design cost of the yaw system of the wind turbine is reduced.

Description

Technical Field

[0001] This invention relates to the technical field of wind power generation, and in particular to a method and system for controlling the ultimate load of the yaw system under the condition of single-blade jamming of a wind turbine. Background Technology

[0002] The loads on a wind turbine mainly come from gravity, inertial, and aerodynamic loads. These are the primary factors affecting the turbine's operating status and the basis for its operation control. Loads not only relate to the turbine's safety but also directly impact the strength of its components.

[0003] As the wind power industry enters the era of grid parity, wind turbines are gradually undergoing technological innovation and cost reduction optimization towards larger rotors, longer blades, and lighter towers. From the design and development stage, the operating load of the wind turbine is a key factor determining the strength of the turbine's subsystems and components. How to operate the wind turbine at a lower load level is the foundation for cost reduction and optimization.

[0004] Currently, the main basis for wind turbine design is the IEC standard. This standard evaluates and analyzes various complex operating conditions that the entire machine may encounter. During the overall design phase, it is essential to ensure that the wind turbine meets the load requirements of all extreme and fatigue conditions throughout its service life. However, extreme operating conditions of wind turbines are generally accompanied by turbine failures, such as power grid outages, pitch failures, and turbine overspeed. Among these pitch failures, there is a condition where a single blade may become stuck. Under this condition, any one of the three blades of the wind turbine may become stuck, causing aerodynamic imbalance among the three blades. This can easily lead to a sudden increase in load on the yaw system and hub system, thereby affecting the overall operating status of the wind turbine.

[0005] Current jammed propeller conditions typically involve a shutdown operation, but the control methods for the wind turbine during shutdown are complex and varied. Generally, an emergency shutdown is initiated, during which pitch control is applied to the two non-jammed propellers. Existing load control technology for jammed propeller conditions uses pitch control based on the yaw motor's current, but this places higher demands on the yaw motor's hardware, increasing its development costs.

[0006] Existing load control technologies for jammed propellers include separate control of non-jammed propeller blades. However, this requires shielding the hardware safety chain of the non-jammed propeller blades, which carries certain risks. When controlling a non-jammed propeller blade separately during a single blade jamming process, it cannot be guaranteed that the non-jammed propeller blade will not trigger a pitch change fault.

[0007] Existing load control technologies for stuck propeller conditions include pitch control based on the fore-and-aft displacement of the nacelle during shutdown, switching the pitch rate at the maximum fore-and-aft displacement in both the positive and negative directions. However, the blade unbalanced load is significant under stuck propeller conditions, and frequent switching of the pitch rate may exacerbate this unbalanced load. Furthermore, the reliability of pitch control depends on the accuracy of the data from the fore-and-aft displacement sensors. Summary of the Invention

[0008] The primary objective of this invention is to overcome the shortcomings and deficiencies of the prior art and provide a method for controlling the ultimate load of the yaw system under the single-blade jamming condition of a wind turbine. By controlling the pitch of the unjammed blades and the torque of the generator, the load on the yaw system is reduced, the safety of the wind turbine is improved, and the design cost of the wind turbine yaw system is reduced.

[0009] The second objective of this invention is to provide a control system for the ultimate load of the yaw system under the condition of single-blade jamming in a wind turbine.

[0010] The first objective of this invention is achieved through the following technical solution: a method for controlling the ultimate load of the yaw system under the single-blade jamming condition of a wind turbine. This method requires determining whether the wind turbine is in a single-blade jamming state. The determination is made based on the pitch angle deviation between any two blades. When the deviation value is greater than a threshold, a single-blade jamming fault is triggered, and the turbine enters a shutdown mode. During the shutdown process, the measured root load of the three blades is used as input. The yaw system load is calculated through coordinate system transformation. Pitch control is performed on the non-jammed blades based on the yaw system load, and the generator torque is controlled simultaneously, so that the yaw system load of the wind turbine during the shutdown process meets the design requirements.

[0011] Furthermore, the method for controlling the ultimate load of the yaw system under the single-blade jamming condition of a wind turbine includes the following steps:

[0012] 1) Measure the root load of three blades;

[0013] Stress sensors are installed at the root of the three blades. The stress sensors convert the deformation of the strain gauges into a linear or arbitrary functional relationship of resistance or voltage output. The changes in resistance or voltage are used to measure the changes in the load at the root of the three blades, which then become the input for the load control of the single blade jamming condition.

[0014] 2) Judgment of single-blade jamming conditions;

[0015] The system determines the blade jamming fault based on the pitch angle deviation between any two blades. If the deviation exceeds the threshold, a single blade jamming fault is triggered, and the system enters shutdown mode and executes step 3). Otherwise, it jumps back to step 1.

[0016] 3) Convert blade root loads into yaw system loads;

[0017] The blade root load signal measured in step 1) is filtered by a high-pass filter. The filtered blade root load signal is used as the input of the single blade jamming load controller. The controller performs coordinate system transformation based on the blade root load to calculate the yaw system load. The coordinate system is transformed from the blade root coordinate system to the yaw coordinate system.

[0018] 4) Pitch control is performed based on the yaw system load, and generator torque is controlled based on the generator speed;

[0019] Based on the wind turbine design requirements, the yaw system load threshold and the maximum yaw system load under wind speed conditions for single blade jamming are determined. Then, the ratio of expected load to actual load is calculated based on the threshold and the maximum yaw system load. The yaw system load control target is then calculated based on the ratio of expected load to actual load. Different yaw system load control targets correspond to different pitch rates. Finally, the yaw system load calculated in step 3) is compared with the yaw system load control target, and the corresponding pitch rate is selected to perform pitch control on the non-jammed blades. At the same time, during shutdown, the generator torque needs to be controlled according to the generator speed. This control is achieved by the wind turbine's converter responding to the generator torque setpoint.

[0020] Further, in step 1), let X1 be the distance between the predetermined position P1 of the blade root of blade 1 and the blade root position, X2 be the distance between the predetermined position P2 of the blade root of blade 2 and the blade root position, and X3 be the distance between the predetermined position P3 of the blade root of blade 3 and the blade root position. The predetermined positions P1, P2, and P3 of the blade roots of the three blades are the installation positions of the stress sensor. The distances X1, X2, and X3 between the predetermined positions of the blade roots and the blade root position are the distances between the sensor positions and the blade roots. X1, X2, and X3 need to be calibrated according to the actual field conditions.

[0021] Furthermore, in step 3), the coordinate system transformation relationship is as follows:

[0022]

[0023] In the formula, M y The load in the Y direction at the center of the impeller hub, where the Y direction is the Y direction in the hub coordinate system, M z The load in the Z-direction of the yaw system, where Z-direction is the Z-direction in the yaw coordinate system, M blade1 M is the root load measured for blade 1. blade2 M is the root load measured for blade 2. blade3 θ is the blade root load measured for blade 3, and θ is the impeller azimuth angle.

[0024] Furthermore, in step 4), the yaw system load calculated in step 3) is M. z Based on the wind turbine's design requirements, design the threshold Q corresponding to the yaw system load. z Based on the wind speed W condition for the single-blade jamming condition described in the IEC standard, determine the maximum yaw system load M under the wind speed W condition. zmax The percentage P between the expected load and the actual load is calculated. z1 =M zmax / Q z -1, Yaw system load control target M z1 =Q z *(1-P z1 According to the yaw system load control target M z1 Able to obtain the yaw system load control target M z2 =M z1 *P z2 Yaw system load control target M z3 =M z2 *P z3 P z2 P z3 The yaw system load control percentage is determined based on actual simulation calculation experience, and the yaw system load control target M is... z1 With a strain gauge propeller rate of V1, the yaw system load control target M z2 With a strain gauge propeller rate of V2, the yaw system load control target M z3 The corresponding strain gauge pitch rate is V3; after the wind turbine enters shutdown mode, when the calculated yaw system load M... z >M z1 At that time, the pitch rate is set to V1, when M z2 <M z <M z1 At that time, the pitch rate is calculated by dynamic interpolation between pitch rates V1 and V2, when M z3 <M z <M z2 At that time, the pitch rate is calculated by dynamic interpolation between pitch rates V2 and V3, when M z <M z3 When the wind turbine is out of grid connection, the pitch rate is set to V3; when the wind turbine is out of grid connection, the pitch rate is set to V4 until the wind turbine pitch angle reaches the stop feathering angle.

[0025] Furthermore, in step 4), the generator torque is controlled based on the currently measured generator speed S, and the generator torque control target T1 corresponds to the generator rated speed S. rate The generator torque control target T2 corresponds to the generator software overspeed threshold S. over Let the generator's grid-connected speed be S. syncWhen the generator speed S < S sync When the generator speed is S, the generator torque is set to 0; when the generator speed is S... sync <S<S rate When the generator torque is linearly interpolated between 0 and T1, the generator speed S is calculated; rate <S<S over When the generator torque is calculated using linear interpolation between T1 and T2; when the generator speed S > S over At that time, the generator torque is set to T2.

[0026] The second objective of this invention is achieved through the following technical solution: a yaw system ultimate load control system for single-blade jamming conditions in wind turbines, comprising:

[0027] The blade root load measurement module installs stress sensors at the blade root positions of the three blades. The stress sensors convert the deformation of the strain gauges into a linear or arbitrary functional relationship of resistance or voltage output. The changes in resistance or voltage are used to measure the changes in the blade root load of the three blades, which then become the input for subsequent single-blade jamming load control.

[0028] The single-blade jamming condition judgment module judges the pitch angle deviation between any two blades. When the deviation value is greater than the threshold, it triggers a single-blade jamming fault and enters the shutdown mode.

[0029] The load conversion module filters the blade root load signal measured by the blade root load measurement module through a high-pass filter. The filtered blade root load signal is used as the input of the single blade jamming load controller. In the controller, the coordinate system is converted to the yaw system load based on the blade root load.

[0030] The non-jammed blade pitch control module determines the yaw system load threshold and the maximum yaw system load under wind speed conditions of single blade jamming, based on the wind turbine design requirements. Then, it calculates the ratio of expected load to actual load based on the threshold and the maximum yaw system load, and then calculates the yaw system load control target based on the ratio of expected load to actual load. Different yaw system load control targets correspond to different pitch rates. Finally, it compares the yaw system load calculated by the load conversion module with the yaw system load control target and selects the corresponding pitch rate to perform pitch control on the non-jammed blade.

[0031] The generator torque control module controls the generator torque based on the generator speed. This control is achieved by responding to the generator torque setpoint through the wind turbine's converter.

[0032] Furthermore, in the load transformation module, the coordinate system transformation relationship is as follows:

[0033]

[0034] In the formula, M y The load in the Y direction at the center of the impeller hub, where the Y direction is the Y direction in the hub coordinate system, M z The load in the Z-direction of the yaw system, where Z-direction is the Z-direction in the yaw coordinate system, M blade1 M is the root load measured for blade 1. blade2 M is the root load measured for blade 2. blade3 θ is the blade root load measured for blade 3, and θ is the impeller azimuth angle.

[0035] Furthermore, in the non-clamped blade pitch control module, the yaw system load calculated by the load conversion module is M. z Based on the wind turbine's design requirements, design the threshold Q corresponding to the yaw system load. z Based on the wind speed W condition for the single-blade jamming condition described in the IEC standard, determine the maximum yaw system load M under the wind speed W condition. zmax The percentage P between the expected load and the actual load is calculated. z1 =M zmax / Q z -1, Yaw system load control target M z1 =Q z *(1-P z1 According to the yaw system load control target M z1 Able to obtain the yaw system load control target M z2 =M z1 *P z2 Yaw system load control target M z3 =M z2 *P z3 P z2 P z3 The yaw system load control percentage is determined based on actual simulation calculation experience, and the yaw system load control target M is... z1 With a strain gauge propeller rate of V1, the yaw system load control target M z2 With a strain gauge propeller rate of V2, the yaw system load control target M z3 The corresponding strain gauge pitch rate is V3; after the wind turbine enters shutdown mode, when the calculated yaw system load M... z >M z1 At that time, the pitch rate is set to V1, when M z2 <M z <M z1 At that time, the pitch rate is calculated by dynamic interpolation between pitch rates V1 and V2, when M z3 <M z <Mz2 At that time, the pitch rate is calculated by dynamic interpolation between pitch rates V2 and V3, when M z <M z3 When the wind turbine is out of grid connection, the pitch rate is set to V3; when the wind turbine is out of grid connection, the pitch rate is set to V4 until the wind turbine pitch angle reaches the stop feathering angle.

[0036] Furthermore, in the generator torque control module, the generator torque is controlled based on the currently measured generator speed S, and the generator torque control target T1 corresponds to the generator rated speed S. rate The generator torque control target T2 corresponds to the generator software overspeed threshold S. over Let the generator's grid-connected speed be S. sync When the generator speed S < S sync When the generator speed is S, the generator torque is set to 0; when the generator speed is S... sync <S<S rate When the generator torque is linearly interpolated between 0 and T1, the generator speed S is calculated; rate <S<S over When the generator torque is calculated using linear interpolation between T1 and T2; when the generator speed S > S over At that time, the generator torque is set to T2.

[0037] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0038] 1. Regarding the existing load control for blade jamming conditions, this invention, based on the existing hardware configuration of the wind turbine, stops the turbine after a single blade jamming fault is triggered. During the shutdown process, pitch control and torque control are performed. This does not impose higher design requirements on the yaw motor, nor does it increase the requirements on the original yaw system hardware configuration of the wind turbine, thus avoiding increased hardware development costs.

[0039] 2. Regarding the existing load control for stuck blade conditions, this invention does not affect the pitch fault settings of the safety chain in the main control system. Based on the original fault alarm logic, this invention improves the single-blade stuck blade load control logic during shutdown without changing the wind turbine safety chain fault alarm logic. When a single blade stuck blade fault is triggered, separate pitch control is performed on the non-stuck blades, but it will not affect the triggering of other pitch faults on the non-stuck blades, thus avoiding impacting the wind turbine safety chain fault alarm and preventing any impact on the overall safety of the wind turbine.

[0040] 3. Regarding the existing load control for stuck propellers, this invention calculates the yaw system load by performing coordinate system transformation based on the blade root load. The yaw system load is then used to control the non-stuck propeller blades, ensuring that the yaw system load meets design requirements. Moreover, the control based on the yaw system load is more direct, and the load fluctuation of the yaw system is more stable. Pitch control based on the yaw system load will not exacerbate the unbalanced load of the three blades due to frequent pitch changes, thus avoiding frequent pitch changes of the non-stuck propeller blades and reducing the unbalanced load of the three blades.

[0041] 4. In response to existing load control for propeller jamming conditions, this invention adds generator torque control logic during shutdown, enabling the generator to adjust in real time according to the generator speed during shutdown, optimizing the load state of the transmission chain system during shutdown, thereby reducing the impact on the yaw system load. Attached Figure Description

[0042] Figure 1 This is a control principle diagram of the method of the present invention.

[0043] Figure 2 The timing diagram of the yaw Mz load for turning the single-blade jamming load control on and off.

[0044] Figure 3 This is a schematic diagram of the coordinate system for the yaw system.

[0045] Figure 4 This is an architecture diagram of the system of the present invention. Detailed Implementation

[0046] The present invention will be further described below with reference to specific embodiments.

[0047] Example 1

[0048] This embodiment provides a method for controlling the ultimate load of the yaw system under the condition of single-blade jamming in a wind turbine. (See also...) Figure 1 As shown, this method requires determining whether the wind turbine is in a single-blade jamming state. This is done based on the pitch angle deviation between any two blades. When the deviation exceeds a threshold, a single-blade jamming fault is triggered, initiating a shutdown mode. During shutdown, the measured root loads of the three blades are used as input. After coordinate system transformation, the yaw system load is calculated. Pitch control is applied to the non-jammed blades based on the yaw system load, while simultaneously controlling the generator torque. This ensures that the yaw system load during shutdown meets design requirements. The timing sequence for closing and opening the single-blade jamming load control yaw Mz load is shown in [reference needed]. Figure 2 As shown; it specifically includes the following steps:

[0049] 1) Measure the root load of three blades;

[0050] Stress sensors are installed at the root positions of the three blades. These stress sensors convert the deformation of strain gauges into a linear or arbitrary functional relationship of resistance or voltage output. The changes in resistance or voltage are used to measure the changes in the load at the root of the three blades, which then become the input for subsequent load control of single-blade jamming conditions. Let X1 be the distance from the predetermined root position P1 of blade 1 to the root position, X2 be the distance from the predetermined root position P2 of blade 2 to the root position, and X3 be the distance from the predetermined root position P3 of blade 3 to the root position. The predetermined root positions P1, P2, and P3 of the three blades are the installation positions of the stress sensors. The distances X1, X2, and X3 from the predetermined root positions to the root positions are the distances from the sensor positions to the blade roots. X1, X2, and X3 need to be calibrated according to the actual field conditions.

[0051] 2) Judgment of single-blade jamming conditions;

[0052] The system determines the propeller pitch angle deviation between any two blades. If the deviation exceeds a threshold, a single blade jamming fault is triggered, and the system enters shutdown mode, proceeding to step 3. Otherwise, it jumps back to step 1.

[0053] 3) Convert blade root loads into yaw system loads;

[0054] The blade root load signal measured in step 1) is filtered by a high-pass filter. The filtered blade root load signal is used as the input to the single-blade jamming load controller. In this controller, the yaw system load is calculated by coordinate system transformation based on the blade root load. The coordinate system transformation from the blade root coordinate system to the yaw coordinate system is as follows:

[0055]

[0056] In the formula, M y The load in the Y direction at the center of the impeller hub, where the Y direction is the Y direction in the hub coordinate system, M z The load in the Z-direction of the yaw system, where Z-direction is the Z-direction in the yaw coordinate system, M blade1 M is the root load measured for blade 1. blade2 M is the root load measured for blade 2. blade3 The blade root load is measured for blade 3, and θ is the impeller azimuth angle. For example... Figure 3 As shown, F x F is the thrust in the direction of the incoming wind speed. y F is the thrust perpendicular to the direction of the transmission chain. z M is the force along the axial direction of the tower. x M y M z For F x Fy F z Bending moment generated by forces in three directions.

[0057] 4) Pitch control is performed based on the yaw system load, and generator torque is controlled based on the generator speed;

[0058] Step 3) The calculated yaw system load is M z Based on the wind turbine's design requirements, design the threshold Q corresponding to the yaw system load. z Based on the wind speed W condition for the single-blade jamming condition described in the IEC standard, determine the maximum yaw system load M under the wind speed W condition. zmax The percentage P between the expected load and the actual load is calculated. z1 =M zmax / Q z -1, Yaw system load control target M z1 =Q z *(1-P z1 According to the yaw system load control target M z1 Able to obtain the yaw system load control target M z2 =M z1 *P z2 Yaw system load control target M z3 =M z2 *P z3 P z2 P z3 The yaw system load control percentage is determined based on actual simulation calculation experience, and the yaw system load control target M is... z1 With a strain gauge propeller rate of V1, the yaw system load control target M z2 With a strain gauge propeller rate of V2, the yaw system load control target M z3 The corresponding strain gauge pitch rate is V3; after the wind turbine enters shutdown mode, when the calculated yaw system load M... z >M z1 At that time, the pitch rate is set to V1, when M z2 <M z <M z1 At that time, the pitch rate is calculated by dynamic interpolation between pitch rates V1 and V2, when M z3 <M z <M z2 At that time, the pitch rate is calculated by dynamic interpolation between pitch rates V2 and V3, when M z <M z3 When the wind turbine is out of grid connection, the pitch rate is set to V3; when the wind turbine is out of grid connection, the pitch rate is set to V4 until the wind turbine pitch angle reaches the stop feathering angle.

[0059] Simultaneously, during shutdown, the generator torque needs to be controlled based on the currently measured generator speed S. This control is achieved through the wind turbine's converter responding to the generator torque setpoint. The generator torque control target T1 corresponds to the generator's rated speed S. rate The generator torque control target T2 corresponds to the generator software overspeed threshold S. over Let the generator's grid-connected speed be S. sync When the generator speed S < S sync When the generator speed is S, the generator torque is set to 0; when the generator speed is S... sync <S<S rate When the generator torque is linearly interpolated between 0 and T1, the generator speed S is calculated; rate <S<S over When the generator torque is calculated using linear interpolation between T1 and T2; when the generator speed S > S over At that time, the generator torque is set to T2.

[0060] Example 2

[0061] This embodiment provides a limit load control system for the yaw system under single-blade jamming conditions in wind turbines. (See also...) Figure 4 As shown, the system includes the following functional modules:

[0062] The blade root load measurement module installs stress sensors at the blade root positions of the three blades. The stress sensors convert the deformation of the strain gauges into a linear or arbitrary functional relationship of resistance or voltage output. The changes in resistance or voltage are used to measure the changes in the blade root load of the three blades, which then become the input for subsequent single-blade jamming load control.

[0063] The single-blade jamming condition judgment module judges the pitch angle deviation between any two blades. When the deviation value is greater than the threshold, it triggers a single-blade jamming fault and enters the shutdown mode.

[0064] The load conversion module filters the blade root load signal measured by the blade root load measurement module through a high-pass filter. The filtered blade root load signal is used as the input of the single blade jamming load controller. In the controller, the coordinate system is converted to the yaw system load based on the blade root load.

[0065] The non-jammed blade pitch control module determines the yaw system load threshold and the maximum yaw system load under wind speed conditions of single blade jamming, based on the wind turbine design requirements. Then, it calculates the ratio of expected load to actual load based on the threshold and the maximum yaw system load, and then calculates the yaw system load control target based on the ratio of expected load to actual load. Different yaw system load control targets correspond to different pitch rates. Finally, it compares the yaw system load calculated by the load conversion module with the yaw system load control target and selects the corresponding pitch rate to perform pitch control on the non-jammed blade.

[0066] The generator torque control module controls the generator torque based on the generator speed. This control is achieved by responding to the generator torque setpoint through the wind turbine's converter.

[0067] In the load transformation module, the coordinate system transformation relationship is as follows:

[0068]

[0069] In the formula, M y The load in the Y direction at the center of the impeller hub, where the Y direction is the Y direction in the hub coordinate system, M z The load in the Z-direction of the yaw system, where Z-direction is the Z-direction in the yaw coordinate system, M blade1 M is the root load measured for blade 1. blade2 M is the root load measured for blade 2. blade3 θ is the blade root load measured for blade 3, and θ is the impeller azimuth angle.

[0070] In the non-clamped blade pitch control module, the yaw system load calculated by the load conversion module is M. z Based on the wind turbine's design requirements, design the threshold Q corresponding to the yaw system load. z Based on the wind speed W condition for the single-blade jamming condition described in the IEC standard, determine the maximum yaw system load M under the wind speed W condition. zmax The percentage P between the expected load and the actual load is calculated. z1 =M zmax / Q z -1, Yaw system load control target M z1 =Q z *(1-P z1 According to the yaw system load control target M z1 Able to obtain the yaw system load control target M z2 =M z1 *P z2 Yaw system load control target M z3 =M z2 *Pz3 P z2 P z3 The yaw system load control percentage is determined based on actual simulation calculation experience, and the yaw system load control target M is... z1 With a strain gauge propeller rate of V1, the yaw system load control target M z2 With a strain gauge propeller rate of V2, the yaw system load control target M z3 The corresponding strain gauge pitch rate is V3; after the wind turbine enters shutdown mode, when the calculated yaw system load M... z >M z1 At that time, the pitch rate is set to V1, when M z2 <M z <M z1 At that time, the pitch rate is calculated by dynamic interpolation between pitch rates V1 and V2, when M z3 <M z <M z2 At that time, the pitch rate is calculated by dynamic interpolation between pitch rates V2 and V3, when M z <M z3 When the wind turbine is out of grid connection, the pitch rate is set to V3; when the wind turbine is out of grid connection, the pitch rate is set to V4 until the wind turbine pitch angle reaches the stop feathering angle.

[0071] In the generator torque control module, the generator torque is controlled based on the currently measured generator speed S, and the generator torque control target T1 corresponds to the generator rated speed S. rate The generator torque control target T2 corresponds to the generator software overspeed threshold S. over Let the generator's grid-connected speed be S. sync When the generator speed S < S sync When the generator speed is S, the generator torque is set to 0; when the generator speed is S... sync <S<S rate When the generator torque is linearly interpolated between 0 and T1, the generator speed S is calculated; rate <S<S over When the generator torque is calculated using linear interpolation between T1 and T2; when the generator speed S > S over At that time, the generator torque is set to T2.

[0072] The above-described embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Therefore, any changes made in accordance with the shape and principle of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for controlling the ultimate load of the yaw system under single-blade jamming conditions in wind turbines, characterized in that, This method requires determining whether the wind turbine is in a single-blade jamming state. This is done based on the pitch angle deviation between any two blades. When the deviation exceeds a threshold, a single-blade jamming fault is triggered, initiating a shutdown mode. During shutdown, the measured root loads of the three blades are used as input. After coordinate system transformation, the yaw system load is calculated. Based on the yaw system load, pitch control is applied to the non-jammed blades, and simultaneously, the generator torque is controlled to ensure that the yaw system load meets design requirements during shutdown. The method includes the following steps: 1) Measure the root load of the three blades; Stress sensors are installed at the root of the three blades. The stress sensors convert the deformation of the strain gauges into a linear or arbitrary functional relationship of resistance or voltage output. The changes in resistance or voltage are used to measure the changes in the load at the root of the three blades, which then become the input for the load control of the single blade jamming condition. 2) Judgment of single-blade jamming conditions; The judgment is made based on the pitch angle deviation between any two blades. When the deviation value is greater than the threshold, a single blade jamming fault is triggered, the machine enters the shutdown mode, and step 3) is executed; otherwise, the machine jumps back to step 1). 3) Convert blade root loads into yaw system loads; The blade root load signal measured in step 1) is filtered by a high-pass filter. The filtered blade root load signal is used as the input of the single blade jamming load controller. The controller performs coordinate system transformation based on the blade root load to calculate the yaw system load. The coordinate system is transformed from the blade root coordinate system to the yaw coordinate system. 4) Pitch control is performed based on the yaw system load, and generator torque is controlled based on the generator speed; Based on the wind turbine design requirements, the yaw system load threshold and the maximum yaw system load under wind speed conditions for single blade jamming are determined. Then, the ratio of expected load to actual load is calculated based on the threshold and the maximum yaw system load. The yaw system load control target is then calculated based on the ratio of expected load to actual load. Different yaw system load control targets correspond to different pitch rates. Finally, the yaw system load calculated in step 3) is compared with the yaw system load control target, and the corresponding pitch rate is selected to perform pitch control on the non-jammed blades. At the same time, during shutdown, the generator torque needs to be controlled according to the generator speed. This control is achieved by the wind turbine's converter responding to the generator torque setpoint.

2. The method for controlling the ultimate load of the yaw system under single-blade jamming conditions of a wind turbine according to claim 1, characterized in that: In step 1), let X1 be the distance between the predetermined position P1 of blade 1 and the blade root position, X2 be the distance between the predetermined position P2 of blade 2 and the blade root position, and X3 be the distance between the predetermined position P3 of blade 3 and the blade root position. The predetermined positions P1, P2, and P3 of the three blade roots are the installation positions of the stress sensor. The distances X1, X2, and X3 between the predetermined positions of the blade roots and the blade root position are the distances between the sensor position and the blade root. X1, X2, and X3 need to be calibrated according to the actual field conditions.

3. The method for controlling the ultimate load of the yaw system under single-blade jamming conditions of a wind turbine according to claim 1, characterized in that: In step 3), the coordinate system transformation relationship is as follows: In the formula, M y The load in the Y direction at the center of the impeller hub, where the Y direction is the Y direction in the hub coordinate system, M z The load in the Z-direction of the yaw system, where Z-direction is the Z-direction in the yaw coordinate system, M blade1 M is the root load measured for blade 1. blade2 M is the root load measured for blade 2. blade3 θ is the blade root load measured for blade 3, and θ is the impeller azimuth angle.

4. The method for controlling the ultimate load of the yaw system under single-blade jamming conditions of a wind turbine according to claim 1, characterized in that: In step 4), the yaw system load calculated in step 3) is M. z Based on the wind turbine's design requirements, design the threshold Q corresponding to the yaw system load. z Based on the wind speed W condition for the single-blade jamming condition described in the IEC standard, determine the maximum yaw system load M under the wind speed W condition. zmax The percentage P between the expected load and the actual load is calculated. z1 =M zmax / Q z -1, Yaw system load control target M z1 =Q z *(1-P z1 According to the yaw system load control target M z1 Able to obtain the yaw system load control target M z2 =M z1 *P z2 Yaw system load control target M z3 =M z2 *P z3 P z2 P z3 The yaw system load control percentage is determined based on actual simulation calculation experience, and the yaw system load control target M is... z1 With a strain gauge propeller rate of V1, the yaw system load control target M z2 With a strain gauge propeller rate of V2, the yaw system load control target M z3 The corresponding strain gauge pitch rate is V3; after the wind turbine enters shutdown mode, when the calculated yaw system load M... z >M z1 At that time, the pitch rate is set to V1, when M z2 <M z <M z1 At that time, the pitch rate is calculated by dynamic interpolation between pitch rates V1 and V2, when M z3 <M z <M z2 At that time, the pitch rate is calculated by dynamic interpolation between pitch rates V2 and V3, when M z <M z3 When the wind turbine is out of grid connection, the pitch rate is set to V3; when the wind turbine is out of grid connection, the pitch rate is set to V4 until the wind turbine pitch angle reaches the stop feathering angle.

5. The method for controlling the ultimate load of the yaw system under single-blade jamming conditions of a wind turbine according to claim 1, characterized in that: In step 4), the generator torque is controlled based on the currently measured generator speed S, and the generator torque control target T1 corresponds to the generator rated speed S. rate The generator torque control target T2 corresponds to the generator software overspeed threshold S. over Let the generator's grid-connected speed be S. sync When the generator speed S < S sync When the generator speed is S, the generator torque is set to 0; when the generator speed is S... sync <S<S rate When the generator torque is linearly interpolated between 0 and T1, the generator speed S is calculated; rate <S over When the generator torque is calculated linearly between T1 and T2; when the generator speed S>S over At that time, the generator torque is set to T2.​ 6. A limit load control system for the yaw system under single-blade jamming conditions of a wind turbine, characterized in that, include: The blade root load measurement module installs stress sensors at the blade root positions of the three blades. The stress sensors convert the deformation of the strain gauges into a linear or arbitrary functional relationship of resistance or voltage output. The changes in resistance or voltage are used to measure the changes in the blade root load of the three blades, which then become the input for subsequent single-blade jamming load control. The single-blade jamming condition judgment module judges the pitch angle deviation between any two blades. When the deviation value is greater than the threshold, it triggers a single-blade jamming fault and enters the shutdown mode. The load conversion module filters the blade root load signal measured by the blade root load measurement module through a high-pass filter. The filtered blade root load signal is used as the input of the single blade jamming load controller. In the controller, the coordinate system is converted to the yaw system load based on the blade root load. The non-jammed blade pitch control module determines the yaw system load threshold and the maximum yaw system load under wind speed conditions of single blade jamming, based on the wind turbine design requirements. Then, it calculates the ratio of expected load to actual load based on the threshold and the maximum yaw system load, and then calculates the yaw system load control target based on the ratio of expected load to actual load. Different yaw system load control targets correspond to different pitch rates. Finally, it compares the yaw system load calculated by the load conversion module with the yaw system load control target and selects the corresponding pitch rate to perform pitch control on the non-jammed blade. The generator torque control module controls the generator torque based on the generator speed. This control is achieved by responding to the generator torque setpoint through the wind turbine's converter.

7. The ultimate load control system for the yaw system under single-blade jamming condition of a wind turbine as described in claim 6, characterized in that: In the load transformation module, the coordinate system transformation relationship is as follows: In the formula, M y The load in the Y direction at the center of the impeller hub, where the Y direction is the Y direction in the hub coordinate system, M z The load in the Z-direction of the yaw system, where Z-direction is the Z-direction in the yaw coordinate system, M blade1 M is the root load measured for blade 1. blade2 M is the root load measured for blade 2. blade3 θ is the blade root load measured for blade 3, and θ is the impeller azimuth angle.

8. The ultimate load control system for the yaw system under single-blade jamming condition of a wind turbine as described in claim 6, characterized in that: In the non-clamped blade pitch control module, the yaw system load calculated by the load conversion module is M. z Based on the wind turbine's design requirements, design the threshold Q corresponding to the yaw system load. z Based on the wind speed W condition for the single-blade jamming condition described in the IEC standard, determine the maximum yaw system load M under the wind speed W condition. zmax The percentage P between the expected load and the actual load is calculated. z1 =M zmax / Q z -1, Yaw system load control target M z1 =Q z *(1-P z1 According to the yaw system load control target M z1 Able to obtain the yaw system load control target M z2 =M z1 *P z2 Yaw system load control target M z3 =M z2 *P z3 P z2 P z3 The yaw system load control percentage is determined based on actual simulation calculation experience, and the yaw system load control target M is... z1 With a strain gauge propeller rate of V1, the yaw system load control target M z2 With a strain gauge propeller rate of V2, the yaw system load control target M z3 The corresponding strain gauge pitch rate is V3; after the wind turbine enters shutdown mode, when the calculated yaw system load M... z >M z1 At that time, the pitch rate is set to V1, when M z2 <M z <M z1 At that time, the pitch rate is calculated by dynamic interpolation between pitch rates V1 and V2, when M z3 <M z <M z2 At that time, the pitch rate is calculated by dynamic interpolation between pitch rates V2 and V3, when M z <M z3 When the wind turbine is out of grid connection, the pitch rate is set to V3; when the wind turbine is out of grid connection, the pitch rate is set to V4 until the wind turbine pitch angle reaches the stop feathering angle.

9. The ultimate load control system for the yaw system under single-blade jamming condition of a wind turbine as described in claim 6, characterized in that: In the generator torque control module, the generator torque is controlled based on the currently measured generator speed S, and the generator torque control target T1 corresponds to the generator rated speed S. rate The generator torque control target T2 corresponds to the generator software overspeed threshold S. over Let the generator's grid-connected speed be S. sync When the generator speed S < S sync When the generator speed is S, the generator torque is set to 0; when the generator speed is S... sync <S<S rate When the generator torque is linearly interpolated between 0 and T1, the generator speed S is calculated; rate <S<S over When the generator torque is calculated linearly between T1 and T2; when the generator speed S>S over At that time, the generator torque is set to T2.

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