Impeller shutdown method and device for reducing unbalanced load of impeller caused by single blade jamming

Abstract

The present application provides an impeller shutdown method and device for reducing the unbalanced load of the impeller caused by a single blade jamming. The method includes: when detecting a single blade jamming fault, implementing a first feathering strategy to adjust the pitch angles of other blades of the impeller to a preset pitch angle; when detecting that the pitch angles of other blades of the impeller are adjusted to the preset pitch angle, obtaining the impeller speed; when detecting that the obtained impeller speed is greater than a preset speed, controlling a mechanical braking device to brake the impeller; when detecting that the obtained impeller speed is reduced to the preset speed, controlling the mechanical braking device to withdraw; and implementing a second feathering strategy to adjust the pitch angles of other blades of the impeller to a feathered pitch angle; wherein, when the pitch angles of other blades of the impeller are at the feathered pitch angle, the impeller speed is close to zero and the impeller shuts down. This impeller shutdown method introduces a mechanical braking device, reduces the amplitude of the unbalanced load of the impeller, and reduces the life loss of the components of the unit.

Description

Technical Field

[0001] The present invention relates to the technical field of wind turbine generators, and more particularly, to a method and device for stopping the impeller to reduce the unbalanced load of the impeller caused by a single blade jamming. Background Art

[0002] When a single blade on the impeller jams, the difference between the pitch angle of the jammed blade and the pitch angles of other blades will cause a huge unbalanced force on the impeller. This huge unbalanced force may cause local structural failure or damage to various components of the wind turbine generator (hereinafter referred to as the wind turbine or the unit), such as the main shaft, main bearing, main frame, and nacelle.

[0003] Regarding the unbalanced force that the impeller may bear during the operation of the wind turbine, in the structural design stage, the strength of each component is usually increased by increasing the size of each component, or other components for coping with the unbalanced load are additionally provided. These technical measures taken for the unbalanced load increase the complexity, manufacturing cost, and operation cost of the components and the wind turbine.

[0004] Generally, during the operation of the unit, once a single blade jamming fault occurs (such as the pitch bearing jamming and the blade cannot be pitched), in order to ensure the structural safety and integrity of the unit, it is no longer possible to generate electricity using wind energy, and emergency shutdown measures must be taken, including impeller shutdown and generator shutdown. Summary of the Invention

[0005] In view of the above problems, the present application provides a method and device for stopping the impeller to reduce the unbalanced load of the impeller caused by a single blade jamming, so as to reduce the unbalanced load of the impeller caused by a single blade jamming and improve the operation safety of the unit.

[0006] In a first aspect, the present application provides a method for stopping the impeller to reduce the unbalanced load of the impeller caused by a single blade jamming, including:

[0007] When it is detected that a single blade jamming fault occurs, execute a first feathering strategy to adjust the pitch angles of other blades of the impeller to a preset pitch angle;

[0008] When it is detected that the pitch angles of other blades of the impeller are adjusted to the preset pitch angle, obtain the impeller speed;

[0009] When it is detected that the obtained impeller speed is greater than a preset speed, control the mechanical braking device to brake the impeller;

[0010] When it is detected that the obtained impeller speed is reduced to the preset speed, control the mechanical braking device to withdraw; and

[0011] Execute a second feathering strategy to adjust the pitch angles of other blades of the impeller to the feathering pitch angle;

[0012] Among them, when the pitch angles of the other blades of the impeller are the feathering pitch angles, the rotational speed of the impeller is close to zero and the impeller stops.

[0013] Further, the implementation of the first feathering strategy to adjust the pitch angles of the other blades of the impeller to preset pitch angles includes:

[0014] The first feathering strategy includes a first set of pitch control commands;

[0015] Control the pitch control devices respectively corresponding to the other blades of the impeller to execute the first set of pitch control commands, so that the other blades of the impeller pitch respectively until the pitch angles of the other blades of the impeller increase to the preset pitch angles;

[0016] Among them, during the process of the pitch angles of the other blades of the impeller increasing to the preset pitch angles, it is detected that the obtained rotational speed of the impeller decreases.

[0017] Further, after detecting the occurrence of a single blade jamming failure, it further includes:

[0018] Obtain the rotational speed of the impeller;

[0019] When it is detected that the obtained rotational speed of the impeller is greater than the preset rotational speed, execute the first feathering strategy to adjust the pitch angles of the other blades of the impeller to the preset pitch angles.

[0020] Further, the control of the mechanical brake device to brake the impeller includes:

[0021] Generate multiple brake torque control commands;

[0022] Control the mechanical brake device to execute the multiple brake torque control commands to brake the impeller, so that the rotational speed of the impeller is reduced to the preset rotational speed.

[0023] Further, the implementation of the second feathering strategy to adjust the pitch angles of the other blades of the impeller to the feathering pitch angles includes:

[0024] The second feathering strategy includes a second set of pitch control commands;

[0025] Control the pitch control devices respectively corresponding to the other blades of the impeller to execute the second set of pitch control commands, so that the other blades of the impeller pitch respectively until the pitch angles of the other blades of the impeller increase to the feathering pitch angles;

[0026] Among them, during the process of the pitch angles of the other blades of the impeller increasing to the feathering pitch angles, it is detected that the obtained rotational speed of the impeller decreases.

[0027] Further, it further includes:

[0028] For a target wind turbine generator set, obtain the ultimate load of the impeller and determine the preset pitch angle and the preset rotational speed:

[0029] Establish a simulation model of the target wind turbine generator set, and the output of the simulation model includes the unbalanced load of the impeller;

[0030] Taking the candidate preset pitch angle, the candidate preset rotational speed, and the ultimate load of the impeller as initial conditions, run the simulation model within the full operating condition profile corresponding to the target wind turbine generator set to simulate the single-blade pitch-locking fault;

[0031] When the unbalanced load of the impeller output by the simulation model is not greater than the ultimate load, determine the candidate preset pitch angle and the candidate preset rotational speed as the available preset pitch angle and the preset rotational speed.

[0032] In a second aspect, the present application provides an impeller shutdown device for reducing the unbalanced load of the impeller caused by single-blade pitch-locking, including:

[0033] A first pitch-feathering strategy control unit, configured to execute a first pitch-feathering strategy when detecting a single-blade pitch-locking fault, so as to adjust the pitch angles of other blades of the impeller to the preset pitch angle;

[0034] A mechanical brake control unit, when detecting that the pitch angles of other blades of the impeller are adjusted to the preset pitch angle, obtains the rotational speed of the impeller; when detecting that the obtained rotational speed of the impeller is greater than the preset rotational speed, controls the mechanical brake device to brake the impeller; when detecting that the obtained rotational speed of the impeller is reduced to the preset rotational speed, controls the mechanical brake device to withdraw;

[0035] A second pitch-feathering strategy control unit, configured to execute a second pitch-feathering strategy to adjust the pitch angles of other blades of the impeller to the pitch-feathering pitch angle; wherein, when the pitch angles of other blades of the impeller are at the pitch-feathering pitch angle, the rotational speed of the impeller is close to zero and the impeller stops.

[0036] In a third aspect, the present application provides a computer device, including a memory and a processor, the memory stores a computer program, and when the processor executes the computer program, it implements the impeller shutdown method for reducing the unbalanced load of the impeller caused by single-blade pitch-locking as described in the first aspect.

[0037] In a fourth aspect, the present application provides a wind turbine generator set, including:

[0038] The impeller shutdown device for reducing the unbalanced load of the impeller caused by single-blade pitch-locking as described in the second aspect;

[0039] An impeller, the impeller is provided with a plurality of blades;

[0040] A mechanical brake device, the mechanical brake device is connected to the main shaft or the high-speed shaft of the impeller.

[0041] The impeller shutdown method and device for reducing the unbalanced load of the impeller caused by a single blade jamming proposed by the present invention introduce a mechanical braking device. During the emergency shutdown process of a single blade jamming, it successively experiences the first pneumatic braking stage, the mechanical braking stage, and the second pneumatic braking stage. After experiencing a dynamic transition, the impeller speed tends to be stable, reducing the amplitude of the unbalanced load of the impeller, which is beneficial to shortening the time consumed from the occurrence of a single blade jamming to the emergency shutdown, and can also reduce the life loss of the unit components caused by the unbalanced load of the impeller. Description of the Drawings

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0043] Figure 1 It is a schematic flow chart of the impeller shutdown method for reducing the unbalanced load of the impeller caused by a single blade jamming according to an embodiment of the present invention;

[0044] Figure 2 It is a schematic composition diagram of the impeller shutdown device for reducing the unbalanced load of the impeller caused by a single blade jamming according to an embodiment of the present invention;

[0045] Figure 3 It is another control flow chart of the impeller shutdown method for reducing the unbalanced load of the impeller caused by a single blade jamming according to an embodiment of the present invention;

[0046] Figure 4 It is a schematic diagram of the static hub coordinate system according to an embodiment of the present invention;

[0047] Figure 5A It is the time curve of the static hub bending moment My of the impeller corresponding to different control methods when a jamming fault occurs in a certain type of wind turbine generator;

[0048] Figure 5B It is the time curve of the static hub bending moment Mz of the impeller corresponding to different control methods when a jamming fault occurs in a certain type of wind turbine generator;

[0049] Figure 5C It is the time curve of the static hub bending moment Myz of the impeller corresponding to different control methods when a jamming fault occurs in a certain type of wind turbine generator;

[0050] Figure 6 It is the time curve of the impeller speed corresponding to different control methods when a jamming fault occurs in a certain type of wind turbine generator. Detailed Embodiments

[0051] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part rather than all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0052] Revolutions Per Minute, r / min.

[0053] A wind turbine (hereinafter referred to as a wind turbine or a unit) includes an impeller, a main shaft driven and rotated by the impeller, a mechanical braking device provided on the main shaft or the high-speed shaft, a generator driven by the main shaft, a pitch system for driving the pitch of the blades, a nacelle, and a tower. Usually, three blades are installed on the impeller. At the same impeller speed, when in wind farms with different wind speeds and directions, there is an optimal windward angle for the blades, and at this time, the wind energy utilization coefficient is relatively the largest.

[0054] Each blade of the wind turbine forms an angle with the impeller rotation plane (i.e., the plane perpendicular to the main shaft XN), which is called the pitch angle. During the power generation state, when the pitch angle is about 0°, the wind energy utilization coefficient is relatively the largest; if the pitch angle continues to increase, the wind energy utilization coefficient will decrease significantly. Specifically, when the wind speed is lower than the rated wind speed, the impeller speed is adjusted to track the maximum wind speed to absorb wind energy as much as possible; when the wind speed is higher than the rated wind speed, by adjusting the pitch angles of the blades, the generator power can be kept constant. When the pitch angles of all the blades are increased to about 90°, the impeller speed approaches zero (i.e., is basically zero), and the impeller stops or is stationary. This angle range is called the blade stop angle. When the wind turbine starts, controlling the pitch angle of the blade to decrease from the stop angle to the working angle is called blade pitching. When the wind turbine stops, controlling the pitch angle of the blade to decrease from the working angle to the stop angle is called feathering.

[0055] As mentioned above, during the operation of the unit, the scenarios where pitch adjustment is required include: when exceeding the rated power of the unit, the blades pitch to track the wind energy; when the wind turbine starts, blade pitching is performed; when the wind turbine stops, feathering is performed.

[0056] The pitch system includes a pitch drive device, a pitch motor, and a pitch motor brake. Usually, the pitch motor brake is coaxial with the pitch motor and is installed at the tail of the pitch motor to play a braking role. Currently, the 2MW - 6MW models are the main types of wind turbines in China. The rated power of the unit and the length of the blades are continuously increasing, and the blade torque that the pitch needs to overcome is also increasing synchronously. Thus, the torque load capacity of the pitch motor and the pitch motor brake is also increasing synchronously.

[0057] Generally, a pitch motor and a pitch motor brake are respectively provided independently for each blade. Each pitch motor can adjust the pitch angle of each blade. For example, the pitch motor drives the blade to rotate following the pitch bearing, thereby adjusting the angle formed between the blade and the impeller rotation plane. Independent pitch control is developed on the basis of unified pitch control, which means that each blade independently changes its pitch angle according to the received pitch control command. The three blades can have different aerodynamic performances, so it can effectively solve the problem of uneven load in time and space caused by inevitable interference factors such as wind shear effect, tower shadow effect, and turbulence effect in unified pitch control, thereby reducing the possibility of blade fatigue damage and outputting stable power.

[0058] When controlling the unit to stop, multiple different pitch rates, such as 2° per second, 3° per second, or 10° per second, can be set in segments according to the values of the pitch angles to be turned by each blade, such as 80°, or according to the initial pitch angle during blade jamming, such as 15°, until the impeller stops rotating.

[0059] Blade jamming means that the blade is jammed and cannot rotate, so the pitch angle of the blade cannot change following the pitch control command. For example, the blade is jammed due to the inability of the pitch bearing to rotate. When a single-blade jamming fault occurs, the wind turbine needs to stop as soon as possible and handle this jamming fault. This is because after a single-blade jamming, the impeller will lose its aerodynamic balance, and the huge unbalanced force will cause deformation or local structural failure or damage to various components of the wind turbine, such as the main shaft, main bearing, main frame, and nacelle of the wind turbine, resulting in loss of the unit's service life. In addition, the huge unbalanced force caused by single-blade jamming also significantly increases the design cost of the unit.

[0060] The impeller stopping method for reducing the impeller unbalanced load caused by single-blade jamming provided by the embodiments of the present invention can effectively reduce the impeller unbalanced load, reduce the design cost of the unit, and extend the service life of the wind power generating set.

[0061] As Figure 1 shown, the impeller stopping method for reducing the impeller unbalanced load caused by single-blade jamming in the embodiments of the present invention includes the following steps:

[0062] S10: When detecting that a single-blade jamming fault occurs, execute the first feathering strategy to adjust the pitch angles of the other blades of the impeller to a preset pitch angle;

[0063] S20: When detecting that the pitch angles of the other blades of the impeller are adjusted to the preset pitch angle, obtain the impeller speed;

[0064] When detecting that the obtained impeller speed is greater than the preset speed, control the mechanical brake device to brake the impeller;

[0065] When detecting that the obtained impeller speed is reduced to the preset speed, control the mechanical brake device to withdraw; and

[0066] S30: Execute the second feathering strategy to adjust the pitch angles of other blades of the impeller to the feathering pitch angle;

[0067] Wherein, when the pitch angles of other blades of the impeller are at the feathering pitch angle, the rotational speed of the impeller is close to zero and the impeller stops.

[0068] In the above step S10, detecting a single blade jamming fault can be that if the difference between the pitch angle of any one of the three blades and the pitch angles of the other two blades reaches a preset value, such as 3.5°, it is determined that there is a single blade jamming. Detecting a single blade jamming fault can also be that if it is detected that the pitch angle of any blade cannot change following its pitch control command, it is determined that the blade has jammed.

[0069] The above step S10 corresponds to the first pneumatic braking stage, and by adjusting the pitch angles of other blades of the impeller, the rotational speed of the impeller is decreased; the above step S20 corresponds to the mechanical braking stage, and by controlling the mechanical braking device to brake the impeller, the rotational speed of the impeller is decreased; the above step S30 corresponds to the second pneumatic braking stage, and by adjusting the pitch angles of other blades of the impeller, the rotational speed of the impeller is decreased to zero.

[0070] In this way, when a single blade jamming fault occurs, the pitch control system is controlled to feather other blades of the impeller to a preset pitch angle to reduce the rotational speed of the impeller; subsequently, the mechanical braking device is controlled to intervene to reduce the rotational speed of the impeller to a preset rotational speed; when it is detected that the rotational speed of the impeller has decreased to the preset rotational speed, the mechanical braking device is controlled to withdraw, and the pitch control system is controlled to feather other blades of the impeller to the feathering pitch angle to reduce the rotational speed of the impeller to zero. In this way, the unit is safely shut down.

[0071] In some embodiments, a variety of detection elements can be arranged at multiple parts of the impeller to detect the unbalanced load of the impeller. The method for detecting the unbalanced load of the impeller can refer to the existing publicly disclosed solutions and will not be elaborated here.

[0072] Reference Figure 5A 、 Figure 5B 、and Figure 5C, the impeller shutdown method for reducing the unbalanced load of the impeller caused by the single-blade stuck propeller is executed. During the impeller shutdown process, the unbalanced load of the impeller gradually decays after experiencing multiple cycles of oscillation. Compared with the traditional shutdown method, the amplitude of the unbalanced load of the impeller is significantly reduced. After the unbalanced load of the impeller is reduced, the accumulated fatigue damage of each component is small, which can indirectly extend the service life of the components. And, after the unbalanced load of the impeller is reduced, the components of the impeller and the components with a transmission relationship or connection relationship with the impeller (including all tower top components, such as impellers, hubs, blades, main bearings, main shafts, main frames, nacelles, yaw systems, yaw bearings) can be designed to be lighter and smaller, so that during the process of decreasing the impeller speed, the detected unbalanced load of the impeller is not greater than the preset limit load of each component.

[0073] As described above, unlike the traditional shutdown method, in which each blade that is not stuck is pitched from the initial pitch angle when the blade is stuck to the shutdown angle, the impeller shutdown method of this embodiment introduces a mechanical brake device, and in the emergency shutdown process of a single blade stuck, the first pneumatic brake stage, the mechanical brake stage, and the second pneumatic brake stage are sequentially experienced. After implementing this three-stage shutdown control scheme, the impeller speed tends to be stable after undergoing dynamic transition, reducing the amplitude of the impeller unbalanced load, which is conducive to shortening the time consumed from the occurrence of a single blade stuck to the emergency shutdown, and can also reduce the life loss of unit components caused by the impeller unbalanced load.

[0074] The impeller shutdown method of this embodiment can reduce the unbalanced load of the impeller caused by a single blade stuck during the shutdown process, can reduce the degree of unbalanced impeller load to a lower level, and reduce the cost of unit components by reducing the unbalanced load.

[0075] In this way, in order to solve the problem of huge unbalanced force of the impeller during the emergency shutdown of the fan due to a single-blade stuck fault, the impeller shutdown method of this embodiment proposes a three-stage shutdown control scheme, so that the impeller switches from a single-blade stuck to other non-stuck blades to smooth the propellers, thereby reducing the amplitude of the impeller unbalanced force during the shutdown process, reducing the safety risks that may be caused by overload of various components of the unit when the blade is stuck, and helping to reduce the design cost of the components of the unit.

[0076] In some embodiments, for the impeller after it stops rotating, it is also necessary to handle the stuck blades, and after the stuck blade fault is eliminated, control the stuck blades to feather, so as to further relieve the unbalanced load state of the impeller. And then, the three blades are pitched separately, and each blade is opened to a pitch angle suitable for the current wind speed in the wind farm, and then the power generation state is switched.

[0077] In some embodiments, executing a first feathering strategy to adjust the pitch angles of other blades of the impeller to a preset pitch angle includes:

[0078] The first feathering strategy includes a first set of pitch control commands;

[0079] Control the pitch control devices corresponding to the other blades of the impeller to execute the first set of pitch control commands, so that the other blades of the impeller pitch respectively until the pitch angles of the other blades of the impeller increase to the preset pitch angle.

[0080] In some embodiments, during the process of increasing the pitch angle of the other blades of the impeller to the preset pitch angle, it is detected that the obtained unbalanced load of the impeller is not greater than its limit load, and it is detected that the obtained impeller speed decreases.

[0081] Above, the first set of pitch control commands includes multiple sets of time-related continuous curves with the same number as the number of non-jammed blades, or an instruction sequence arranged in chronological order at a predetermined interval, which can be pre-generated or generated in real time.

[0082] Generally, when the impeller speed is relatively high when the blade jamming fault triggers an emergency stop, such as Figure 6 shown as 1200 rpm. At this time, the degree of aerodynamic layout imbalance caused by a single blade jamming is very high. If no emergency stop measure is taken, referring to Figure 5A , Figure 5B and Figure 5C , the static hub bending moments My, Mz, and Myz are relatively high.

[0083] As Figure 6 shown, in the first aerodynamic braking stage I, control the pitch systems of the other non-jammed blades to pitch the blades connected to them to change the aerodynamic layout of the impeller and achieve aerodynamic braking. During this process, the pitch angle difference between the jammed blade and the non-jammed blades is gradually increasing, the amplitude of the unbalanced force is also continuously increasing, the impeller speed is gradually decreasing, and all components of the impeller and the unit with a connection or transmission relationship with the impeller are in a state of bearing the unbalanced force of the impeller.

[0084] At the end of the first aerodynamic braking stage, each non-jammed blade has a preset pitch angle. It should be understood that when pitching the non-jammed blades, the control strategy of the generator can be adjusted accordingly, and the generated power can be reduced accordingly by changing the excitation, etc., to match the reduced impeller speed.

[0085] As Figure 6 shown, when a certain type of wind turbine generator set has a blade jamming fault and executes the aforementioned impeller shutdown method, at the end of the first aerodynamic braking stage I, the non-jammed blades have a preset pitch angle. For example, the impeller speed is correspondingly 1000 rpm. And the preset speed corresponding to this type of wind turbine is 900 rpm.

[0086] As described above, at the end of the first pneumatic braking stage, corresponding to the preset pitch angle, the impeller speed is usually greater than the preset speed. During the process of increasing the pitch angles of the other blades of the impeller to the preset pitch angle, the pitch angle of the jammed blade remains unchanged at the initial pitch angle, and the difference between the pitch angles of the other blades of the impeller and the pitch angle of the jammed blade further increases, resulting in a further increase in the unbalanced load of the impeller. Therefore, it is necessary to introduce a mechanical braking device into the emergency shutdown control of a single-blade jam to prevent the difference between the pitch angles of the other blades of the impeller and the pitch angle of the jammed blade from further increasing, and use the gradually decreasing impeller speed to further reduce the amplitude of the impeller unbalanced load.

[0087] In some embodiments, after detecting a single-blade jam fault, it further includes:

[0088] Obtain the impeller speed;

[0089] When it is detected that the obtained impeller speed is greater than the preset speed, execute the first feathering strategy to adjust the pitch angles of the other blades of the impeller to the preset pitch angle.

[0090] When the fan triggers an emergency shutdown due to a single-blade jam fault, the wind speed, impeller speed, initial blade angles of each blade, initial unbalanced load of the impeller, and power of the generator may vary. When the jam fault triggers an emergency shutdown, if it is detected that the obtained impeller speed is not greater than the preset speed, the aforementioned three-stage shutdown control method is not executed, thereby simplifying the impeller shutdown control logic.

[0091] In some embodiments, controlling the mechanical braking device to brake the impeller includes:

[0092] Generate a plurality of braking torque control commands;

[0093] Control the mechanical braking device to execute a plurality of braking torque control commands to brake the impeller so that the impeller speed is reduced to the preset speed.

[0094] In some embodiments, during the process of reducing the impeller speed to the preset speed, it is detected that the obtained impeller unbalanced load is not greater than its limit load.

[0095] As described above, the plurality of braking torque control commands include a continuous curve related to time, or a sequence of braking torque commands arranged in chronological order at a predetermined interval, which can be pre-generated or generated in real time.

[0096] The multiple braking torque control instructions during the mechanical braking phase may vary. During the mechanical braking phase, corresponding to the multiple braking torque control instructions, within multiple control cycles, the mechanical braking device controls the friction plates or brake pads it sets to act on the main shaft or high-speed shaft with different damping torques. For example, the mechanical braking device can be provided with a brake control unit and a mechanical braking mechanism (including brake pads or friction plates). The brake control unit controls the mechanical braking mechanism to perform braking actions with different braking effects on the main shaft or high-speed shaft according to the received braking torque control instructions.

[0097] For example Figure 6 As shown, during the mechanical braking phase II, the pitch angles of the other non-jammed blades remain unchanged at the aforementioned preset pitch angles, so the aerodynamic layout of the impeller does not change. After the mechanical braking device intervenes, the friction plates or brake pads set by the mechanical braking device act on the main shaft or high-speed shaft connected to the impeller with different frictional torques and damping torques to further reduce the impeller speed.

[0098] During the mechanical braking phase II, the jammed blade maintains its initial pitch angle unchanged, and the pitch angles of the other non-jammed blades remain unchanged at the aforementioned preset pitch angles. The pitch angle difference between the blades remains unchanged, and each component of the impeller and the unit with a connection or transmission relationship with the impeller is in a state of bearing unbalanced loads. Referring to Figure 5A 、 Figure 5B and Figure 5C , the mechanical damping provided by the mechanical braking device causes the impeller speed to gradually decrease. The gradually decreasing impeller speed causes the forces on the blades when rotating in the wind field to change, which is beneficial to reducing the amplitude of the impeller unbalanced load.

[0099] When the impeller speed is adjusted to the preset speed, the mechanical braking phase II ends. At this time, the friction plates or brake pads set by the mechanical braking device release the main shaft or high-speed shaft. It should be understood that during the mechanical braking phase II, the control strategy of the generator can be adjusted accordingly, and the generated power can be reduced by changing the excitation, etc., to match the reduced impeller speed.

[0100] In this way, the impeller shutdown method of this embodiment introduces the damping torque provided by the mechanical braking device and the impeller speed as input variables for controlling the impeller shutdown during emergency shutdown, enhancing the applicability and scope of the shutdown control method.

[0101] For example Figure 6 As shown, for a certain type of wind turbine generator set with a blade jamming fault, the aforementioned impeller shutdown method is executed. When the impeller speed decreases to 900 rpm, the mechanical braking device is controlled to release the main shaft or high-speed shaft, and the mechanical braking phase II ends. Compared with before the mechanical braking device intervenes, after the mechanical braking device intervenes, the impeller speed is reduced by about 100 rpm.

[0102] Mechanical brake devices with different capacities and different blade parameters of the fan configuration may provide different damping torques. By reasonably configuring the damping torque of the mechanical brake device, when a single-blade jamming fault occurs and emergency shutdown is performed, the aforementioned three-stage shutdown method is executed. In the mechanical brake stage II, the mechanical brake device will not be damaged or fail, such as overheating; when the damping torque provided by the mechanical brake device is transmitted to rotating components such as the gearbox and generator located behind the main shaft on the drive train, these rotating components can also bear the corresponding rotational torque without strength damage or failure.

[0103] In some embodiments, a second feathering strategy is executed to adjust the pitch angles of the other blades of the impeller to the feathering pitch angle, including:

[0104] The second feathering strategy includes a second set of pitch control commands;

[0105] Control the pitch control devices respectively corresponding to the other blades of the impeller to execute the second set of pitch control commands, so that the other blades of the impeller pitch respectively until the pitch angles of the other blades of the impeller increase to the feathering pitch angle respectively.

[0106] In some embodiments, during the process that the pitch angles of the other blades of the impeller increase from the aforementioned preset pitch angle to the feathering pitch angle, it is detected that the obtained unbalanced load of the impeller is not greater than its limit load, and it is detected that the obtained impeller speed decreases.

[0107] Above, the second set of pitch control commands includes multiple sets of time-related continuous curves with the same number as the number of non-jamming blades, or an instruction sequence arranged in chronological order at a predetermined interval, which can be pre-generated or generated in real time.

[0108] As Figure 6 shown, in the second aerodynamic brake stage III, control the pitch system of the other non-jamming blades to pitch the blades connected thereto to change the aerodynamic layout of the impeller and achieve aerodynamic braking. During this process, the pitch angle difference between the jammed blade and the non-jammed blades is gradually increasing, and the impeller and each component of the unit with a connection or transmission relationship with the impeller are all in a state of bearing the unbalanced force of the impeller. However, because the non-jammed blades are gradually adjusted to the feathering pitch angle, the amplitude of the unbalanced force is stable after oscillation; the impeller speed gradually decreases until it approaches zero.

[0109] At the end of the second aerodynamic brake stage, each non-jammed blade has a feathering pitch angle, for example, the feathering pitch angle is between 88-92 degrees; after feathering is completed, the impeller stops and the speed is approximately zero. For example, the wind turbine speed drops below 1 rpm, and the generator speed does not exceed the software overspeed setting value.

[0110] As Figure 6As shown, when a certain type of wind turbine experiences a blade jamming fault and executes the aforementioned impeller shutdown method, at the end of the second pneumatic braking stage III, the wind turbine rotor speed drops to about 1 rpm.

[0111] As described above, at the end of the second pneumatic braking stage, the impeller speed corresponds to the feathering pitch angle and is usually close to zero. Refer to Figure 5A , Figure 5B and Figure 5C . During the process of increasing the pitch angles of the non-jammed blades of the impeller to the feathering pitch angle, the pitch angle of the jammed blade remains unchanged at the initial pitch angle, and the difference between the pitch angles of the other blades of the impeller and the pitch angle of the jammed blade further increases; however, the gradually decreasing impeller speed causes a change in the force on the blades when rotating in the wind field, which is beneficial to reducing the amplitude of the impeller unbalanced load.

[0112] In some embodiments, it further includes, for the target wind turbine, determining a preset pitch angle and a preset speed according to the obtained ultimate torque of the mechanical braking device:

[0113] Establish a simulation model of the target wind turbine, and the output of the simulation model includes the impeller unbalanced load;

[0114] Taking the candidate preset pitch angle, candidate preset speed, and the ultimate load of the impeller of the target wind turbine as initial conditions, run the simulation model within the full operating condition profile corresponding to the target wind turbine to simulate a single blade jamming fault;

[0115] When the impeller unbalanced load output by the simulation model is not greater than its ultimate load, determine the candidate preset pitch angle and candidate preset speed as the available preset pitch angle and preset speed.

[0116] The above is for the already operating wind turbines. Regarding the ultimate torque provided by their mechanical braking devices, for the problem of excessive impeller unbalanced load during the operation and maintenance process, through simulation, the specific values of the corresponding preset pitch angle and preset speed when implementing the aforementioned three-stage impeller shutdown scheme are determined.

[0117] When designing a new wind turbine, the specific values of the corresponding preset pitch angle and preset speed when implementing the aforementioned three-stage impeller shutdown scheme, as well as the ultimate torque that the corresponding mechanical braking device needs to provide, can be determined through simulation.

[0118] In some embodiments, the aforementioned determination of the preset pitch angle and preset speed through multiple rounds of simulation may include the following steps:

[0119] a). Set the initial value P0 of the preset pitch angle and the initial value S0 of the preset speed;

[0120] b). Using the initial value P0 of the preset pitch angle and the initial value S0 of the preset rotational speed, run the simulation model for the single-blade jamming fault condition within the profile from the simulation cut-in wind speed (e.g., 3 m / s wind speed) to the cut-out wind speed (e.g., 20 m / s wind speed).

[0121] c). During the dynamic transition process, check whether the impeller unbalanced load exceeds the load limit value Md within the time period from jamming to feathering to the pitch angle P0. If it exceeds the load limit value Md, then reduce the initial value P0 of the preset pitch angle, and go back to execute steps b) to c). Until the impeller unbalanced load is not greater than the load limit value Md. At this time, record the determined preset pitch angle as P1, and go to execute step d).

[0122] d). After determining the preset pitch angle as P1, continue the simulation:

[0123] Using the preset pitch angle P1 and the initial value S0 of the preset rotational speed, run the simulation model for the single-blade jamming fault condition within the profile from the cut-in wind speed to the cut-out wind speed.

[0124] During the dynamic transition process, check whether the impeller unbalanced load exceeds the load limit value Md within the time period from jamming to feathering to the preset pitch angle P1. If it exceeds the load limit value Md, then reduce the initial value S0 of the preset rotational speed, and go to execute step d). Until the impeller unbalanced load is not greater than the load limit value Md. At this time, record the determined preset rotational speed as S1.

[0125] Above, step c) is the step for determining the preset pitch angle, and step d) is the step for determining the preset rotational speed. In this way, the target pitch angle and the target rotational speed are determined through steps c) and d).

[0126] Above, determining the target pitch angle first and then the target rotational speed is beneficial to shortening the simulation time, reducing the number of simulation rounds, and improving the simulation efficiency.

[0127] In some embodiments, using the simulation model of the wind turbine generator set to perform real-time simulation, the steps for determining parameters such as the preset pitch angle and the preset rotational speed in the aforementioned impeller shutdown method include:

[0128] 11. Determine the preset pitch angle: Establish the simulation model of the wind turbine generator set; with the constraint that the impeller unbalanced load is not greater than its limit load, through simulation, determine the preset pitch angle that other blades need to feather to when a single blade jams at different wind speeds.

[0129] 12. Determine the preset rotational speed: During the process of each blade in feathering to the preset pitch angle without blade jamming, the rotational speed of the impeller will gradually decrease. However, when feathering to the preset pitch angle, the rotational speed of the impeller may still be greater than the preset rotational speed. Therefore, it is necessary to engage the mechanical braking device to further reduce the rotational speed of the impeller and reduce the unbalanced load of the impeller. After the mechanical braking device is activated, the rotational speed of the impeller will gradually decrease. After decreasing to the preset rotational speed, the mechanical braking device is controlled to disengage to continue controlling each blade without blade jamming to feather. With the constraint that the unbalanced load of the impeller is not greater than its limit load, through simulation, when a single blade is jammed at different wind speeds, after other blades feather to the preset pitch angle and then the mechanical braking device is engaged, the preset rotational speed to which it needs to be decreased is determined.

[0130] As Figure 2 shown, the impeller shutdown device 1000 for reducing the unbalanced load of the impeller caused by a single blade jam in the embodiment of the present application includes:

[0131] The first feathering strategy control unit 100 is configured to execute the first feathering strategy to adjust the pitch angles of other blades of the impeller to the preset pitch angle when detecting a single blade jam fault;

[0132] The mechanical braking control unit 200 obtains the rotational speed of the impeller when detecting that the pitch angles of other blades of the impeller are adjusted to the preset pitch angle; controls the mechanical braking device to brake the impeller when detecting that the obtained rotational speed of the impeller is greater than the preset rotational speed; and controls the mechanical braking device to disengage when detecting that the obtained rotational speed of the impeller decreases to the preset rotational speed;

[0133] The second feathering strategy control unit 300 is configured to execute the second feathering strategy to adjust the pitch angles of other blades of the impeller to the feather pitch angle; wherein, when the pitch angles of other blades of the impeller are at the feather pitch angle, the rotational speed of the impeller is close to zero and the impeller shuts down.

[0134] In some embodiments, when using the aforementioned impeller shutdown device 1000 to execute the aforementioned impeller shutdown method, the specific implementation steps include:

[0135] 21. Parameter input: Input various parameters such as the preset pitch angle, preset rotational speed, damping torque of the mechanical braking device, and limit load of the impeller into the shutdown device to be implemented with the logic control algorithm;

[0136] 22. Algorithm transplantation: Transplant the logic control algorithm corresponding to the aforementioned impeller shutdown method to the field controller, such as a PLC equipped with a fieldbus.

[0137] 23. Field test: Trigger a single blade jam fault at the operation site, and let the field controller run the logic control algorithm corresponding to the aforementioned impeller shutdown method to verify the effectiveness of the logic control algorithm.

[0138] In some embodiments, the aforementioned impeller shutdown device 1000 may be a computer device, which includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements the aforementioned impeller shutdown method for reducing the unbalanced load of the impeller caused by a single blade jamming.

[0139] In some embodiments, when the aforementioned impeller shutdown device 1000 is configured in a wind turbine generator set, the wind turbine generator set includes:

[0140] The aforementioned impeller shutdown device 1000 for reducing the unbalanced load of the impeller caused by a single blade jamming;

[0141] An impeller, with multiple blades provided on the impeller;

[0142] A mechanical braking device, which is connected to the main shaft or high-speed shaft of the impeller;

[0143] When a single blade jamming fault occurs, the impeller shutdown device 1000 executes the aforementioned impeller shutdown method for reducing the unbalanced load of the impeller caused by a single blade jamming, so that the impeller switches from jamming to feathering, reducing the amplitude of the unbalanced force of the impeller during the shutdown process and reducing the safety risks that various components of the unit may cause due to overload during jamming.

[0144] Reference Figure 3 , in some embodiments, when this impeller shutdown method is implemented in a certain type of wind turbine, when a single blade jamming fault occurs, first control the other blades of the impeller to feather at a lower pitch-changing speed (e.g., 4° / second) until they feather to a preset pitch angle (e.g., 18°); when it is detected that the other blades of the impeller have feathered to the preset pitch angle, detect whether the impeller speed is greater than the preset speed (e.g., 900 r / min°). If the impeller speed is greater than the preset speed, control the mechanical braking device to engage until it is detected that the impeller speed has decreased to the preset speed, and then control the mechanical braking device to disengage (e.g., the friction plate or brake pad releases and loosens the main shaft or high-speed shaft); subsequently, control the other blades of the impeller to feather to the feathering pitch angle (e.g., 88°) at a higher pitch-changing speed (e.g., 10° / second) to stop the impeller.

[0145] The following combines Figure 4 , Figure 5A , Figure 5B and Figure 5C , and with reference to the time curves of the impeller unbalanced loads respectively obtained when the impeller is shut down using the traditional shutdown method and the method of the embodiments of the present application, specifically illustrate the impeller shutdown method of the embodiments of the present application. Figure 4In this case, with the hub stationary coordinate system as the reference benchmark, the horizontal shaft bending moment My, vertical shaft bending moment Mz, and combined bending moment Myz borne by the blade root of the impeller are shown. Among them, the YN axis and ZN axis are two coordinate axes in the hub stationary coordinate system that are respectively perpendicular to the main shaft XN driven by the impeller. The stationary hub bending moments My, Mz, and Myz in this coordinate system can reflect the unbalanced loads borne by each component of the impeller and the unbalanced loads transmitted to other components of the unit through the impeller.

[0146] Figure 5A The time curve of the stationary hub bending moment My during the process from blade jamming to shutdown is shown. The stationary hub bending moment My is the moment around the coordinate axis YN perpendicular to the main shaft XN. The stationary hub bending moment My mainly affects the main frame. By comparing the time curves, after implementing the impeller shutdown method of the embodiment of the present application, the positive and negative amplitudes of the stationary hub bending moment My borne by the impeller are significantly lower than those of the traditional shutdown method.

[0147] Figure 5B The time curve of the stationary hub bending moment Mz during the process from blade jamming to shutdown is shown. The stationary hub bending moment Mz is the moment around the coordinate axis ZN perpendicular to the main shaft XN. The stationary hub bending moment Mz mainly affects the main frame. By comparing the time curves, after implementing the impeller shutdown method of the embodiment of the present application, the positive and negative amplitudes of the stationary hub bending moment Mz borne by the impeller are significantly lower than those of the traditional shutdown method.

[0148] Figure 5C The time curve of the stationary hub combined bending moment Myz (which is the vector sum of the bending moment My and the bending moment Mz) during the process from blade jamming to shutdown is shown. The stationary hub bending moment Myz is the resultant moment. The stationary hub bending moment Myz mainly affects the main frame, the main shaft, and the main bearing. By comparing the time curves, after implementing the impeller shutdown method of the embodiment of the present application, the positive and negative amplitudes of the stationary hub bending moment Myz borne by the impeller are significantly lower than those of the traditional shutdown method.

[0149] Figure 6 The time curve of the generator speed during the process from blade jamming to shutdown obtained by simulation is shown. It should be understood that after the transmission ratio conversion, the generator speed corresponds to the aforementioned impeller speed. By comparing the time curves, implementing the impeller shutdown method of the embodiment of the present application can make the impeller speed drop to a lower level relatively quickly and be adjusted to a safe state.

[0150] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0151] The above description is illustrative rather than restrictive to the present invention. Those of ordinary skill in the art understand that many modifications, variations or equivalents can be made without departing from the spirit and scope defined by the claims, and all of them will fall within the protection scope of the present invention.

Claims

1. An impeller shutdown method for reducing the unbalanced load of the impeller caused by single-blade jamming, characterized in that, Including: When a single blade jamming fault is detected, execute a first feathering strategy to adjust the pitch angles of other blades of the impeller to a preset pitch angle; When it is detected that the pitch angles of other blades of the impeller are adjusted to the preset pitch angle, obtain the impeller speed; When it is detected that the obtained impeller speed is greater than a preset speed, control the mechanical braking device to brake the impeller; When it is detected that the obtained impeller speed drops to the preset speed, control the mechanical braking device to withdraw; And Execute a second feathering strategy to adjust the pitch angles of other blades of the impeller to the feathering pitch angle; Wherein, when the pitch angles of other blades of the impeller are at the feathering pitch angle, the impeller speed is close to zero and the impeller stops; For a target wind turbine generator set, obtain the ultimate load of the impeller and determine the preset pitch angle and the preset speed: Establish a simulation model of the target wind turbine generator set, and the output of the simulation model includes the unbalanced load of the impeller; Taking the candidate preset pitch angle, the candidate preset speed, and the ultimate load of the impeller as initial conditions, run the simulation model within the full operating condition profile corresponding to the target wind turbine generator set to simulate a single blade jamming fault; When the unbalanced load of the impeller output by the simulation model is not greater than the ultimate load, determine the candidate preset pitch angle and the candidate preset speed as the available preset pitch angle and the preset speed.

2. The impeller stopping method according to claim 1, wherein The execution of the first feathering strategy to adjust the pitch angles of other blades of the impeller to the preset pitch angle includes: The first feathering strategy includes a first set of pitch control commands; Control the pitch control devices respectively corresponding to other blades of the impeller to execute the first set of pitch control commands, so that other blades of the impeller pitch respectively until the pitch angles of other blades of the impeller increase to the preset pitch angle respectively; Wherein, during the process that the pitch angles of other blades of the impeller increase to the preset pitch angle, it is detected that the obtained impeller speed decreases.

3. The impeller stopping method according to claim 1, wherein After it is detected that a single blade jamming fault occurs, it further includes: Obtain the impeller speed; When it is detected that the obtained impeller speed is greater than the preset speed, execute the first feathering strategy to adjust the pitch angles of other blades of the impeller to the preset pitch angle.

4. The impeller stopping method according to claim 1, wherein The control of the mechanical braking device to brake the impeller includes: Generate a plurality of braking torque control commands; Control the mechanical braking device to execute the plurality of braking torque control commands to brake the impeller, so that the impeller speed drops to the preset speed.

5. The impeller stopping method according to claim 3, wherein The execution of the second feathering strategy to adjust the pitch angles of other blades of the impeller to the feathering pitch angle includes: The second feathering strategy includes a second set of pitch control commands; Control the pitch control devices respectively corresponding to other blades of the impeller to execute the second set of pitch control commands, so that other blades of the impeller pitch respectively until the pitch angles of other blades of the impeller increase to the feathering pitch angle respectively; During the process that the pitch angles of other blades of the impeller increase to the feathering pitch angle, it is detected that the obtained rotational speed of the impeller decreases.

6. An impeller shutdown device for reducing the unbalanced load of the impeller caused by a single-blade jamming, characterized in that, It includes: A first feathering strategy control unit, configured to execute a first feathering strategy when it is detected that a single blade jamming fault occurs, so as to adjust the pitch angles of other blades of the impeller to a preset pitch angle; A mechanical brake control unit, when it is detected that the pitch angles of other blades of the impeller are adjusted to the preset pitch angle, obtains the rotational speed of the impeller; when it is detected that the obtained rotational speed of the impeller is greater than a preset rotational speed, controls a mechanical brake device to brake the impeller; When it is detected that the obtained rotational speed of the impeller decreases to the preset rotational speed, controls the mechanical brake device to withdraw; A second feathering strategy control unit, configured to execute a second feathering strategy to adjust the pitch angles of other blades of the impeller to the feathering pitch angle; wherein, when the pitch angles of other blades of the impeller are at the feathering pitch angle, the rotational speed of the impeller is close to zero and the impeller stops; The determining methods of the preset pitch angle and the preset rotational speed include: For a target wind turbine generator set, obtain the ultimate load of the impeller, and determine the preset pitch angle and the preset rotational speed: Establish a simulation model of the target wind turbine generator set, and the output of the simulation model includes the unbalanced load of the impeller; Taking the candidate preset pitch angle, the candidate preset rotational speed, and the ultimate load of the impeller as initial conditions, run the simulation model within the full operating condition profile corresponding to the target wind turbine generator set to simulate a single blade jamming fault; When the unbalanced load of the impeller output by the simulation model is not greater than the ultimate load, determine the candidate preset pitch angle and the candidate preset rotational speed as the available preset pitch angle and the preset rotational speed.

7. A computer device, characterized in that, It includes a memory and a processor, the memory stores a computer program, and when the processor executes the computer program, it implements the impeller stopping method for reducing the impeller unbalanced load caused by a single blade jamming as described in any one of claims 1 to 5.

8. A wind turbine generator, characterized in that, It includes: The impeller stopping device for reducing the impeller unbalanced load caused by a single blade jamming as described in claim 6; An impeller, the impeller is provided with a plurality of blades; A mechanical brake device, the mechanical brake device is connected to the main shaft or the high-speed shaft of the impeller.

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