Clearance protection method and system based on impeller azimuth angle and variable pitch motor current

Abstract

The invention discloses a clearance protection method and system based on an impeller azimuth angle and variable pitch motor current, and the method comprises the steps: obtaining an impeller azimuth angle signal in real time in a fan grid-connected power generation mode; variable-pitch electric driving systems of three blades of the fan send respective variable-pitch motor current signals to the main control PLC in each control task period; according to the arrangement sequence of three blades of the fan in an impeller rotating plane, the main control PLC sequentially judges whether the variable pitch motor current exceeds a preset protection threshold value range or not when each blade skims over a tower drum, that is, when the azimuth angle of the impeller reaches a corresponding preset angle; and the actions of the three blades are controlled according to the judgment result. Within a certain impeller azimuth angle range where the blades skim over the tower drum, if the current value of the blade variable-pitch motor exceeds the set threshold value, the clearance protection control action can be triggered immediately, and the method has the advantages of being capable of adapting to various weathers, high in response speed, high in accuracy, low in cost and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of wind power generation, and in particular to a clearance protection method and system based on the azimuth angle of the impeller and the current of the pitch motor. Background Art

[0002] With the large-scale impeller of wind turbines and the increased flexibility of blades, under the influence of the vertical negative shear wind speed when the blades pass by the tower barrel in the power generation mode, maintaining an appropriate distance, that is, a safe clearance, between the blade tip and the tower barrel is a technical index that needs to be considered key in the control design of wind turbines.

[0003] Currently, the widely applied clearance protection technical solutions on large wind turbines, such as installing a clearance ranging lidar device that can rotate with the nacelle on the nacelle of the wind turbine. Due to the relatively long distance between the clearance ranging lidar and the tip of the rotating blade, in fog, rain, snow or sandstorm weather, the measurement data of the clearance ranging lidar will frequently fail, and it can no longer play a protective role in the safe operation of the blade.

[0004] Currently, the actually applied clearance protection technical solutions also include installing multiple radar ranging protection devices in the circumferential direction of the tower barrel wall of the wind turbine. Although the distance between the clearance ranging radar and the tip of the rotating blade in this solution is relatively close and less affected by bad weather, the installation position of the clearance radar in this solution is fixed. When the wind turbine yaws due to tracking the wind direction, making the axis direction of the nacelle not in the same plane as the clearance ranging radar, the measured value of the clearance radar will be too large, the accuracy of the clearance protection will be reduced, and there is also a large delay in the control system triggering the clearance protection action. Summary of the Invention

[0005] The first object of the present invention is to overcome the deficiencies of the prior art and provide a clearance protection method based on the azimuth angle of the impeller and the current of the pitch motor. When the current value of the blade pitch motor exceeds the set threshold within a certain range of the azimuth angle of the impeller when the blade passes by the tower barrel, it can immediately trigger the clearance protection control action, and has the advantages of being able to adapt to various weather conditions, fast response speed, high accuracy, low cost, etc.

[0006] The second object of the present invention is to provide a clearance protection system based on the azimuth angle of the impeller and the current of the pitch motor.

[0007] The third object of the present invention is to provide a storage medium.

[0008] The fourth object of the present invention is to provide a computing device.

[0009] The first object of the present invention is achieved by the following technical solutions:

[0010] A clearance protection method based on impeller azimuth angle and pitch motor current, comprising:

[0011] In the grid-connected power generation mode of the wind turbine, the impeller azimuth angle signal is acquired in real time;

[0012] In each control task cycle, the pitch electric drive systems of the three blades of the wind turbine send their respective pitch motor current signals to the main control PLC;

[0013] According to the arrangement order of the three blades of the wind turbine in the impeller rotation plane, the main control PLC sequentially judges whether the pitch motor current of each blade exceeds the preset protection threshold range when the blade passes by the tower barrel, that is, when the impeller azimuth angle reaches the corresponding preset angle;

[0014] If the pitch motor current of the blade is less than the lower limit of the preset protection threshold range and the blade is in the control state where the clearance protection logic is not triggered, the main control PLC issues an instruction to maintain the blade angle;

[0015] If the pitch motor current of the blade is greater than the upper limit of the preset protection threshold range and the blade is in the control state where the clearance protection logic is not triggered, the main control PLC issues an instruction to increase the blade angle to the pitch electric drive systems of the three blades, and the three blades retract the pitch at a set rate to increase the clearance;

[0016] If the pitch motor currents of the three blades are all less than the lower limit of the preset protection threshold range and the blades are in the control state where the clearance protection logic is triggered, the main control PLC issues an instruction to decrease the blade angle to the pitch electric drive systems of the three blades, and the three blades open the pitch at a set rate to the normal blade angle.

[0017] Further, an absolute encoder is used to measure and acquire the impeller azimuth angle signal in real time, and the absolute encoder is installed in the hub and can rotate together with the main shaft of the wind turbine.

[0018] Further, when the three blades open the pitch to the normal blade angle at a set rate, the amplitude of the blade angle decrease is the same as the amplitude of the blade angle increase when the three blades retract the pitch at a set rate.

[0019] Further, the pitch electric drive systems of the three blades perform data exchange with the main control PLC through the Profibus bus.

[0020] Further, the preset angles of the impeller azimuth angles corresponding to the three blades are 180deg, 60deg, and 300deg respectively.

[0021] The second object of the present invention is achieved by the following technical solutions:

[0022] A clearance protection system based on the impeller azimuth angle and the pitch motor current, which is used to implement the clearance protection method based on the impeller azimuth angle and the pitch motor current described above, includes an impeller azimuth angle acquisition module, a transmission module, a judgment module, and a control module.

[0023] The impeller azimuth angle acquisition module is used to obtain the impeller azimuth angle signal in real time in the grid-connected power generation mode of the wind turbine.

[0024] The transmission module is used to transmit the pitch motor current signals of the pitch electrical drive systems of the three blades in each control task cycle to the main control PLC.

[0025] The judgment module is used to judge whether the three blades are in the control state of triggering the clearance protection logic, and according to the arrangement order of the three blades in the impeller rotation plane, judge in turn whether the pitch motor current of each blade exceeds the preset protection threshold range when the impeller azimuth angle reaches the corresponding preset angle, that is, when the blade passes by the tower barrel.

[0026] The control module is used to control the actions of the three blades according to the judgment result of the judgment module.

[0027] Further, the control module specifically performs the following operations.

[0028] If the pitch motor current of the blade is less than the lower limit of the preset protection threshold range and the blade is in the control state of not triggering the clearance protection logic, the main control PLC issues an instruction to keep the blade angle.

[0029] If the pitch motor current of the blade is greater than the upper limit of the preset protection threshold range and the blade is in the control state of not triggering the clearance protection logic, the main control PLC issues an instruction to increase the blade angle to the pitch electrical drive systems of the three blades, and the three blades retract the pitch at a set rate to increase the clearance.

[0030] If the pitch motor currents of the three blades are all less than the lower limit of the preset protection threshold range and the blades are in the control state of triggering the clearance protection logic, the main control PLC issues an instruction to decrease the blade angle to the pitch electrical drive systems of the three blades, and the three blades open the pitch to the normal blade angle at a set rate.

[0031] Further, the impeller azimuth angle acquisition module is an absolute encoder, which is installed in the hub and can rotate together with the main shaft of the wind turbine.

[0032] The third object of the present invention is achieved by the following technical solution:

[0033] A storage medium stores a program, and when the program is executed by a processor, it implements the clearance protection method based on the impeller azimuth angle and the pitch motor current described above.

[0034] The fourth object of the present invention is achieved by the following technical solution:

[0035] A computing device includes a processor and a memory for storing programs executable by the processor. The computing device is characterized in that when the processor executes the program stored in the memory, the method for clearance protection based on the azimuth angle of the impeller and the current of the pitch motor described above is implemented.

[0036] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0037] The present invention does not have the problem that the measurement deviation of the blade tip deformation becomes large due to the ranging sensor and the impeller axis not being in the same plane, and is not affected by bad weather such as heavy fog, rain, snow, and sand and dust. It can accurately, quickly, and reliably identify the condition of large clearance and large blade deformation caused by the vertical negative shear wind speed of the blades of a large wind turbine generator in various weather conditions, and then trigger the protection control logic in time to effectively control the blade clearance and avoid the risk of the blade sweeping the tower. Description of the Drawings

[0038] Figure 1 is a flowchart of the method of the present invention.

[0039] Figure 2 is a schematic diagram of the arrangement order of three blades in the impeller rotation plane.

[0040] Figure 3 is a scatter plot pattern 1 of the relationship between the driving torque of the pitch motor of blade 1 and the azimuth angle of the impeller.

[0041] Figure 4 is a scatter plot pattern 2 of the relationship between the driving torque of the pitch motor of blade 1 and the azimuth angle of the impeller.

[0042] Figure 5 is a scatter plot pattern 1 of the relationship between the driving torque of the pitch motor of blade 2 and the azimuth angle of the impeller.

[0043] Figure 6 is a scatter plot pattern 2 of the relationship between the driving torque of the pitch motor of blade 2 and the azimuth angle of the impeller.

[0044] Figure 7 is a scatter plot pattern 1 of the relationship between the driving torque of the pitch motor of blade 3 and the azimuth angle of the impeller.

[0045] Figure 8 is a scatter plot pattern 2 of the relationship between the driving torque of the pitch motor of blade 3 and the azimuth angle of the impeller.

[0046] Figure 9 is a scatter plot of the relationship between the driving torque of the pitch motor of blade 2 and the azimuth angle of the impeller when the simulation software simulates the wind turbine generator experiencing the vertical negative shear condition.

[0047] Figure 10Scatter plot of the measured pitch motor current of blade 1 vs. the azimuth angle of the impeller in a wind farm.

[0048] Figure 11 Scatter plot of the measured pitch motor current of blade 2 vs. the azimuth angle of the impeller in a wind farm.

[0049] Figure 12 Scatter plot of the measured pitch motor current of blade 3 vs. the azimuth angle of the impeller in a wind farm.

[0050] Figure 13 Operating time series of the pitch motor current of blade 1 before and after the tower-sweeping fault occurred on blade 1 in a wind farm.

[0051] Figure 14 Operating time series of the pitch motor current of blade 2 before and after the tower-sweeping fault occurred on blade 1 in a wind farm.

[0052] Figure 15 Operating time series of the pitch motor current of blade 3 before and after the tower-sweeping fault occurred on blade 1 in a wind farm. Specific implementation manners

[0053] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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 some, but not 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.

[0054] Embodiment 1:

[0055] As Figure 1 shown, this embodiment provides a clearance protection method based on the azimuth angle of the impeller and the pitch motor current, including,

[0056] S1. In the grid-connected power generation mode of the wind turbine, an absolute encoder is used to measure and obtain the azimuth angle signal of the impeller in real time. The absolute encoder is installed inside the hub and can rotate together with the main shaft of the wind turbine; three pitch electrical drive system numbers are set as 1, 2, and 3 respectively, and the corresponding blade numbers are 1, 2, and 3 respectively.

[0057] Select the position where blade 1 rotates to the vertical upward as the zero point of the absolute encoder. When the impeller rotates clockwise, the reading of the encoder increases. When the reading of the absolute encoder increases to 360deg, the reading is reset to zero and starts to increase from zero again, repeating the cycle.

[0058] Assume that the three blades are arranged clockwise in the impeller rotation plane in the order of blade 1, blade 2, and blade 3; for blade 1, when the impeller azimuth angle is 90 deg, blade 1 rotates to 3 o'clock on the clock, when the impeller azimuth angle is 180 deg, it corresponds to 6 o'clock on the clock, and when the impeller azimuth angle is 270 deg, it corresponds to 9 o'clock on the clock; for blade 2, when the impeller azimuth angle is 330 deg, blade 2 rotates to 3 o'clock on the clock, when the impeller azimuth angle is 60 deg, blade 2 rotates to 6 o'clock on the clock, and when the impeller azimuth angle is 150 deg, blade 2 rotates to 9 o'clock on the clock; for blade 3, when the impeller azimuth angle is 210 deg, blade 3 rotates to 3 o'clock on the clock, when the impeller azimuth angle is 300 deg, blade 3 rotates to 6 o'clock on the clock, and when the impeller azimuth angle is 30 deg, blade 3 rotates to 9 o'clock on the clock.

[0059] S2. In each control task cycle, the pitch electrical drive systems of the three blades of the fan send their respective pitch motor current signals to the main control PLC, and the pitch electrical drive systems of the three blades exchange data with the main control PLC through the Profibus bus;

[0060] For the pitch electrical drive system that drives the adjustment of the blade pitch angle, according to the pitch motor driving torque in the simulation results of the large wind turbine simulation software and the actually applied pitch motor current, within the normal working range, it approximately satisfies a linear relationship, that is, Τ = K × Ι, where Τ represents the pitch motor driving torque, Ι represents the pitch motor current, and K represents the torque coefficient.

[0061] S3. According to the simulation results of the large wind turbine simulation software under the power generation condition and the operation data of the wind farm, when the blade rotates near 3 o'clock and 9 o'clock on the clock, the driving torque or current of the pitch motor that drives the adjustment of the blade pitch angle usually appears as a peak, and when the blade rotates past the tower barrel and rotates near 6 o'clock on the clock, usually the driving torque or current of the pitch motor is relatively small. Given that there is a linear relationship between the pitch driving torque and the pitch motor current, the time-domain operation timing change trends of the two are basically the same.

[0062] Therefore, the main control PLC determines in turn, according to the arrangement order of the three blades of the fan in the impeller rotation plane, whether the pitch motor current of each blade exceeds the preset protection threshold range when the blade passes by the tower barrel, that is, when the impeller azimuth angle reaches near the corresponding preset angle. In this embodiment, the preset angles of the impeller azimuth angles corresponding to the three blades are 180 deg, 60 deg, and 300 deg respectively.

[0063] S4. If the pitch motor current of the blade is less than the lower limit of the preset protection threshold range and the blade is in the control state where the clearance protection logic is not triggered, the main control PLC issues an instruction to maintain the blade angle;

[0064] If the pitch motor current of the blade is greater than the upper limit of the preset protection threshold range and the blade is in a control state where the clearance protection logic is not triggered, the main control PLC sends an instruction to increase the blade angle to the pitch electrical drive systems of the three blades, and the three blades retract the pitch at a set rate to increase the clearance.

[0065] If the pitch motor current when the three blades pass by the tower barrel in sequence is less than the lower limit of the preset protection threshold range and the blade is in a control state where the clearance protection logic is triggered, the main control PLC sends an instruction to decrease the blade angle to the pitch electrical drive systems of the three blades, and the three blades open the pitch at a set rate to the normal blade angle.

[0066] In this embodiment, when the three blades open the pitch at a set rate to the normal blade angle, the decreasing amplitude of the blade angle is the same as the increasing amplitude of the blade angle when the three blades retract the pitch at a set rate.

[0067] Figure 2 is the arrangement order of the three blades in the impeller rotation plane. Blade 1 is vertically upward corresponding to the impeller azimuth angle of 0deg, and the clockwise arrangement order is 1----2----3. When the three blades rotate clockwise, the impeller azimuth angle increases. When it increases to 360deg, it is set to zero and starts to increase again from 0deg, cycling in turn.

[0068] Figure 3 is the scatter plot pattern 1 of the relationship between the pitch motor driving torque of blade 1 and the impeller azimuth angle statistically based on the simulation results of the simulation software. In this pattern, when blade 1 rotates to around 3 o'clock (impeller azimuth angle 90deg) and around 9 o'clock (280deg) of the clock, the pitch motor driving torque (pitch motor current) appears at a peak, and the pitch motor driving torque (pitch motor current) value is smaller at 6 o'clock (impeller azimuth angle 180deg) of the clock.

[0069] Figure 4 is the scatter plot pattern 2 of the relationship between the pitch motor driving torque of blade 1 and the impeller azimuth angle statistically based on the simulation results of the simulation software. In this pattern, when blade 1 rotates to around 3 o'clock (impeller azimuth angle 90deg) and around 9 o'clock (270deg) of the clock, the pitch motor driving torque (pitch motor current) appears at a peak, and the pitch motor driving torque (pitch motor current) value is smaller at 6 o'clock (impeller azimuth angle 180deg) of the clock.

[0070] Figure 5It is the scatter plot pattern 1 of the relationship between the pitch motor driving torque of blade 2 and the impeller azimuth angle, which is statistically obtained according to the simulation results of the simulation software. In this pattern, when blade 2 rotates to around 3 o'clock (impeller azimuth angle 330deg) and around 9 o'clock (160deg) of the clock, the pitch motor driving torque (pitch motor current) reaches a peak, and the value of the pitch motor driving torque (pitch motor current) is relatively small at 6 o'clock (impeller azimuth angle 60deg) of the clock.

[0071] Figure 6 It is the scatter plot pattern 2 of the relationship between the pitch motor driving torque of blade 2 and the impeller azimuth angle, which is statistically obtained according to the simulation results of the simulation software. In this pattern, when blade 2 rotates to around 3 o'clock (impeller azimuth angle 330deg) and around 9 o'clock (160deg) of the clock, the pitch motor driving torque (pitch motor current) reaches a peak, and the value of the pitch motor driving torque (pitch motor current) is relatively small at 6 o'clock (impeller azimuth angle 60deg) of the clock.

[0072] Figure 7 It is the scatter plot pattern 1 of the relationship between the pitch motor driving torque of blade 3 and the impeller azimuth angle, which is statistically obtained according to the simulation results of the simulation software. In this pattern, when blade 3 rotates to around 3 o'clock (impeller azimuth angle 210deg) and around 9 o'clock (40deg) of the clock, the pitch motor driving torque (pitch motor current) reaches a peak, and the value of the pitch motor driving torque (pitch motor current) is relatively small at 6 o'clock (impeller azimuth angle 300deg) of the clock.

[0073] Figure 8 It is the scatter plot pattern 2 of the relationship between the pitch motor driving torque of blade 3 and the impeller azimuth angle, which is statistically obtained according to the simulation results of the simulation software. In this pattern, when blade 3 rotates to around 3 o'clock (impeller azimuth angle 210deg) and around 9 o'clock (40deg) of the clock, the pitch motor driving torque (pitch motor current) reaches a peak, and the value of the pitch motor driving torque (pitch motor current) is relatively small at 6 o'clock (impeller azimuth angle 300deg) of the clock.

[0074] Figure 9 It is the scatter plot of the relationship between the pitch motor driving torque of blade 2 and the impeller azimuth angle, which is statistically obtained when the simulation software simulates the vertical negative shear of the wind turbine generator set. Before the vertical negative shear occurs (the solid line in the figure), when blade 2 rotates to around 3 o'clock (impeller azimuth angle 330deg) and around 9 o'clock (160deg) of the clock, the pitch motor driving torque (pitch motor current) reaches a peak, and the value of the pitch motor driving torque (pitch motor current) is relatively small at 6 o'clock (impeller azimuth angle 60deg) of the clock; while after experiencing the vertical negative shear (the dashed line in the figure), when blade 2 passes by the tower barrel at 6 o'clock (impeller azimuth angle 60deg), the value of the pitch motor driving torque (pitch motor current) increases very significantly.

[0075] Figure 10 It is a pattern in the scatter plot of the pitch motor current of Blade 1 vs. the impeller azimuth angle under normal operation of the measured wind turbine generator set. In this pattern, when Blade 1 rotates to around 3 o'clock (impeller azimuth angle 90 deg) and around 9 o'clock (280 deg) on the clock, the pitch motor current peaks, and the value of the pitch motor current is relatively small at 6 o'clock (impeller azimuth angle 180 deg) on the clock; it Figure 4 is consistent with the simulation results of the simulation software in

[0076] Figure 11 It is a pattern in the scatter plot of the pitch motor current of Blade 2 vs. the impeller azimuth angle under normal operation of the measured wind turbine generator set. In this pattern, when Blade 2 rotates to around 3 o'clock (impeller azimuth angle 330 deg) and around 9 o'clock (impeller azimuth angle 170 deg) on the clock, the pitch motor current peaks, and at 6 o'clock (impeller azimuth angle 60 deg) on the clock, the value of the pitch motor current is relatively small; it Figure 6 is consistent with the simulation results of the simulation software in

[0077] Figure 12 It is a pattern in the scatter plot of the pitch motor current of Blade 3 vs. the impeller azimuth angle under normal operation of the measured wind turbine generator set. In this pattern, when Blade 3 rotates to around 3 o'clock (impeller azimuth angle 210 deg) and around 9 o'clock (impeller azimuth angle 60 deg) on the clock, the pitch motor current peaks, and at 6 o'clock (impeller azimuth angle 300 deg) on the clock, the value of the pitch motor current is relatively small; it Figure 8 is consistent with the simulation results of the simulation software in

[0078] Figure 13 It is the operating time series of the pitch motor current of Blade 1 before and after the clearance is small and the tower is swept by Blade 1 due to a relatively severe vertical wind speed negative shear in a wind turbine generator set without an impeller azimuth angle sensor in the wind farm. The "0" moment corresponds to the moment when Blade 1 sweeps the tower, that is, the impeller azimuth angle is near 6 o'clock on the clock and the operating value of the pitch motor current is relatively high, thus verifying that a relatively high pitch motor current of the wind turbine generator set corresponds to the phenomenon of the blade sweeping the tower when passing by the tower barrel. For the relationship between the impeller azimuth angle of Blade 1 and the operating pitch motor current, it Figure 3 is consistent with the simulation results of the simulation software in

[0079] Figure 14 It is the operating time series of the pitch motor current of Blade 2 before and after the clearance is small and the tower is swept by Blade 1 due to a relatively severe vertical wind speed negative shear in a wind turbine generator set without an impeller azimuth angle sensor in the wind farm. The "0" moment corresponds to the moment when Blade 1 sweeps the tower. For the relationship between the impeller azimuth angle of Blade 2 and the operating pitch motor current, it Figure 5 is consistent with the simulation results of the simulation software in

[0080] Figure 15 For a wind turbine in a wind farm without an installed impeller azimuth angle sensor, before and after the blade 1 experiences a net clearance small tower-sweeping fault due to a relatively severe negative vertical wind speed shear, the operating time sequence of the pitch motor current of blade 3. The "0" moment corresponds to the moment when blade 1 sweeps the tower. For the relationship between the impeller azimuth angle of blade 3 and the operating pitch motor current, it Figure 7 is consistent with the simulation results of the simulation software in

[0081] Embodiment 2:

[0082] This embodiment provides a net clearance protection system based on the impeller azimuth angle and the pitch motor current, which is used to implement the net clearance protection method based on the impeller azimuth angle and the pitch motor current described in Embodiment 1, and includes an impeller azimuth angle acquisition module, a transmission module, a judgment module, and a control module.

[0083] The impeller azimuth angle acquisition module is used to obtain the impeller azimuth angle signal in real time in the grid-connected power generation mode of the wind turbine;

[0084] The transmission module is used to transmit the pitch motor current signals of the pitch electrical drive systems of the three blades in each control task cycle to the main control PLC;

[0085] The judgment module is used to judge whether the three blades are in the control state of triggering the net clearance protection logic, and according to the arrangement order of the three blades in the impeller rotation plane, sequentially judge whether the pitch motor current of each blade exceeds the preset protection threshold range when the blade sweeps past the tower barrel, that is, when the impeller azimuth angle reaches the corresponding preset angle;

[0086] The control module is used to control the actions of the three blades according to the judgment result of the judgment module; specifically, the following operations are performed.

[0087] If the pitch motor current of the blade is less than the lower limit of the preset protection threshold range and the blade is in the control state where the net clearance protection logic is not triggered, the main control PLC issues an instruction to maintain the blade angle;

[0088] If the pitch motor current of the blade is greater than the upper limit of the preset protection threshold range and the blade is in the control state where the net clearance protection logic is not triggered, the main control PLC issues an instruction to increase the blade angle to the pitch electrical drive systems of the three blades, and the three blades retract the blades at a set rate to increase the net clearance;

[0089] If the pitch motor currents of the three blades are all less than the lower limit of the preset protection threshold range when the three blades sequentially sweep past the tower barrel and the blades are in the control state of triggering the net clearance protection logic, the main control PLC issues an instruction to decrease the blade angle to the pitch electrical drive systems of the three blades, and the three blades open the blades at a set rate to the normal blade angle.

[0090] In this embodiment, the impeller azimuth angle acquisition module can adopt an absolute encoder, which is installed inside the hub and can rotate together with the main shaft of the fan.

[0091] Embodiment 3:

[0092] A storage medium stores a program, which when executed by a processor, implements the clearance protection method based on the impeller azimuth angle and the pitch motor current described in Embodiment 1.

[0093] Embodiment 4:

[0094] A computing device includes a processor and a memory for storing programs executable by the processor. When the processor executes the programs stored in the memory, it implements the clearance protection method based on the impeller azimuth angle and the pitch motor current described in Embodiment 1.

[0095] As mentioned above, only the preferred embodiments of this invention patent are described, but the protection scope of this invention patent is not limited thereto. Any person skilled in the art within the scope disclosed by this invention patent, according to the technical solution and inventive concept of this invention patent, makes equivalent substitutions or changes, and all belong to the protection scope of this invention patent.

Claims

1. A clearance protection method based on impeller azimuth angle and pitch motor current, characterized in that including In the grid-connected power generation mode of the wind turbine, the azimuth angle signal of the impeller is obtained in real time; In each control task cycle, the pitch electric drive systems of the three blades of the wind turbine send their respective pitch motor current signals to the main control PLC; The main control PLC sequentially determines whether the pitch motor current of each blade exceeds the preset protection threshold range when each blade passes by the tower barrel, that is, when the azimuth angle of the impeller reaches the corresponding preset angle, according to the arrangement order of the three blades of the wind turbine in the impeller rotation plane; If the pitch motor current of the blade is less than the lower limit of the preset protection threshold range and the blade is in the control state where the clearance protection logic is not triggered, the main control PLC issues an instruction to maintain the blade angle; If the pitch motor current of the blade is greater than the upper limit of the preset protection threshold range and the blade is in the control state where the clearance protection logic is not triggered, the main control PLC issues an instruction to increase the blade angle to the pitch electric drive systems of the three blades, and the three blades retract the pitch at a set rate to increase the clearance; If the pitch motor currents of the three blades are all less than the lower limit of the preset protection threshold range and the blades are in the control state where the clearance protection logic is triggered, the main control PLC issues an instruction to decrease the blade angle to the pitch electric drive systems of the three blades, and the three blades open the pitch to the normal blade angle at a set rate.

2. The net clearance protection method based on the impeller azimuth angle and the pitch motor current according to claim 1, wherein An absolute encoder is used to measure and obtain the azimuth angle signal of the impeller in real time, and the absolute encoder is installed in the hub and can rotate together with the main shaft of the wind turbine.

3. The net clearance protection method based on the impeller azimuth angle and the variable pitch motor current according to claim 1, wherein When the three blades open the pitch to the normal blade angle at a set rate, the amplitude of the decrease in the blade angle is the same as the amplitude of the increase in the blade angle when the three blades retract the pitch at a set rate.

4. The net clearance protection method based on the impeller azimuth angle and the variable pitch motor current according to claim 1, wherein, The pitch electric drive systems of the three blades exchange data with the main control PLC through the Profibus bus.

5. The net clearance protection method based on the impeller azimuth angle and the pitch motor current according to claim 1, wherein The preset angles of the azimuth angles of the three blades corresponding to the impeller are 180deg, 60deg, and 300deg respectively.

6. A clearance protection system based on the impeller azimuth angle and the pitch motor current, characterized in that A clearance protection method based on the azimuth angle of the impeller and the pitch motor current according to any one of claims 1 to 5 is implemented, including an impeller azimuth angle acquisition module, a transmission module, a judgment module, and a control module. The impeller azimuth angle acquisition module is used to obtain the azimuth angle signal of the impeller in real time in the grid-connected power generation mode of the wind turbine; The transmission module is used to transmit the pitch motor current signals of the pitch electric drive systems of the three blades in each control task cycle to the main control PLC; The judgment module is used to judge whether the three blades are in the control state where the clearance protection logic is triggered, and sequentially judge whether the pitch motor current of each blade exceeds the preset protection threshold range when each blade passes by the tower barrel, that is, when the azimuth angle of the impeller reaches the corresponding preset angle, according to the arrangement order of the three blades in the impeller rotation plane; The control module is used to control the actions of the three blades according to the judgment result of the judgment module.

7. The clearance protection system based on the impeller azimuth angle and the pitch motor current according to claim 6, wherein The control module specifically performs the following operations If the pitch motor current of the blade is less than the lower limit of the preset protection threshold range and the blade is in the control state where the clearance protection logic is not triggered, the main control PLC issues an instruction to maintain the blade angle; If the pitch motor current of the blade is greater than the upper limit of the preset protection threshold range and the blade is in a control state where the clearance protection logic is not triggered, the master PLC sends an instruction to increase the blade angle to the pitch electrical drive systems of the three blades, and the three blades retract the pitch at a set rate to increase the clearance. If the pitch motor currents of the three blades are all less than the lower limit of the preset protection threshold range and the blade is in a control state where the clearance protection logic is triggered, the master PLC sends an instruction to decrease the blade angle to the pitch electrical drive systems of the three blades, and the three blades open the pitch to the normal blade angle at a set rate.

8. The clearance protection system based on the impeller azimuth angle and the pitch motor current according to claim 6, wherein, The impeller azimuth angle acquisition module is an absolute encoder, installed inside the hub and capable of rotating together with the main shaft of the wind turbine.

9. A storage medium stores a program, characterized in that, When the program is executed by the processor, it implements the clearance protection method based on the impeller azimuth angle and the pitch motor current according to any one of claims 1 to 5.

10. A computing device, comprising a processor and a memory for storing processor-executable programs, characterized in that, When the processor executes the program stored in the memory, it implements the clearance protection method based on the impeller azimuth angle and the pitch motor current according to any one of claims 1 to 5.

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