Wind turbine variable pitch system anti typhoon mode control strategy and state machine switching method

Abstract

The application provides a wind turbine variable pitch system typhoon mode control strategy, comprising: when the main control system of the wind turbine identifies a typhoon working condition, triggering the variable pitch system to stop urgently, and collecting three blades to a 91-degree stop position; within a preset time, collecting the three blades to a -90-degree typhoon-resistant position; and putting into variable pitch brake and brake stop. The application also provides a state machine switching method of the wind turbine variable pitch system, when the main control system issues a typhoon stop mode flag bit to the variable pitch system, and the variable pitch system is not faulty, the hardware safety chain signal is normal, and the variable pitch system receives a reset instruction from the main control system, the state machine of the variable pitch system is switched from the emergency stop mode to the typhoon-resistant mode. The application can solve the technical problem that the variable pitch system cannot adjust the pitch angle within 360 degrees, and cannot meet the typhoon-resistant requirement of the wind turbine.

Description

Technical Field

[0001] This invention relates to the field of wind power generation technology, specifically to a typhoon-resistant mode control strategy and state machine switching method for a wind turbine pitch system. Background Technology

[0002] For wind turbine generators, existing designs typically incorporate pre-bending of long, flexible blades. This pre-bending design allows the blades to naturally bend when the turbine is off, generating a limiting torsional moment around the pitch axis under extreme wind speeds. However, during actual operation, if the braking torque of the pitch system is insufficient to counteract this limiting torsional moment under extreme wind speeds, the blades will be blown away, deviating from the feathering position, causing the rotor to accelerate or even overspeed.

[0003] When a typhoon strikes, the extreme wind speeds may exceed the theoretical design limit of the wind turbine generator set. To ensure the safety of the wind turbine generator set's load, the blades need to be positioned at a suitable location using the pitch control system. However, in existing designs, the normal operating angle range of the wind turbine generator set's pitch control system is 0-91°. When the pitch angle is less than 0°, an angle too small fault will be reported, preventing the blades from adjusting their angle arbitrarily within 360 degrees, thus failing to meet the typhoon resistance requirements of the wind turbine generator set. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention proposes a typhoon-resistant mode control strategy and state machine switching method for wind turbine pitch systems. This addresses the technical problem that existing pitch systems cannot allow the blades to adjust their angle arbitrarily within 360 degrees, thus failing to meet the typhoon-resistant requirements of wind turbines.

[0005] The technical solution adopted in this invention is as follows: Firstly, a typhoon-resistant mode control strategy for a wind turbine pitch system is provided, comprising:

[0006] When the main control system of the wind turbine recognizes the outward wind condition, it triggers the pitch system to shut down the turbine and retracts the three blades to the 91-degree shutdown position.

[0007] Within a preset time, the three blades will be adjusted to a typhoon-resistant position of -90°.

[0008] Engage the pitch brake and hold brake to stop the engine.

[0009] Furthermore, when the three blades are retracted to the 91-degree stop position, the main control system sends a flag indicating that it has entered typhoon stop mode to the pitch system, and sends a reset signal, a closed safety chain, and a target position of -90° to the pitch system, switching the pitch system state machine to typhoon-resistant mode.

[0010] Furthermore, when the pitch system state machine switches to typhoon-resistant mode, the pitch system will move the blades out from the current stop position according to the target position of -90°, and pitch the blades to the typhoon-resistant position of -90° within a preset time.

[0011] Furthermore, the preset time is 10 seconds. The three blades change the pitch to -90° in sequence at a pitching speed of -2° / s. After one blade completes its action, there is a 3-second interval before the next blade begins its action.

[0012] Furthermore, a limit switch is provided at a position of -90°.

[0013] Firstly, a method for switching the state machine of a wind turbine pitch system is provided, wherein the state machine includes an automatic operation mode, an emergency stop mode, and a typhoon-resistant mode.

[0014] Furthermore, when the hardware safety chain signal is broken, or the main control system sends a software emergency stop signal to the pitch system, or the pitch system itself malfunctions, or the communication between the pitch system and the main control system times out, the pitch system state machine switches from automatic operation mode to emergency stop mode.

[0015] Furthermore, when the main control system sends a "enter typhoon shutdown mode" flag to the pitch system, and the pitch system itself is fault-free, the hardware safety chain signal is normal, and the pitch system receives a reset command from the main control system, the pitch system state machine switches from emergency stop mode to typhoon resistance mode.

[0016] Furthermore, when the main control system sends an "exit typhoon mode" flag to the pitch system, the hardware safety chain signal is broken, the pitch system itself malfunctions, the main control system sends a software emergency stop signal to the pitch system, and the communication between the pitch system and the main control system times out, the pitch system state machine switches from typhoon mode to emergency stop mode.

[0017] Furthermore, when the main control system sends the target positions of the three blades to the pitch system, all of which are between 0° and 89°, and the pitch system receives the reset command from the main control system, and the communication between the pitch system and the main control system is normal, and the pitch system itself is fault-free, the pitch system state machine switches from emergency stop mode to automatic operation mode.

[0018] As can be seen from the above technical solution, the beneficial technical effects of the present invention are as follows:

[0019] The control strategy of the pitch system was adjusted, and a "typhoon resistance mode" was added to the pitch system state machine. This operating condition was redefined, and the switching logic of the pitch system state machine was redesigned to ensure that when a typhoon arrives, the pitch system can obey the master control command to stop at the -90° typhoon resistance position, which can meet the typhoon resistance requirements of the wind turbine generator set. After the typhoon, it can normally move out of the stop position and return to the stop angle under non-typhoon conditions.

[0020] The pitch control system, while ensuring its own safety, works in conjunction with the entire turbine to complete the typhoon-resistant strategy response, reducing the operational risks of the wind turbine in typhoon conditions and improving the reliability of the wind turbine. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0022] Figure 1 This is a flowchart of the typhoon-resistant control strategy of the pitch system according to an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the working mode switching of the state machine of the pitch system according to an embodiment of the present invention. Detailed Implementation

[0024] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0025] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0026] Example

[0027] When a typhoon strikes, in order to ensure the safety of the wind turbine load and ensure that the braking torque can withstand the ultimate torsional torque under extreme wind speeds, the pitch system needs to be used to adjust the blades to a position of -90°. The -90° position is the angle with the minimum load found through calculation among all the angles of the pitch system's 360-degree rotation.

[0028] The specific typhoon-resistant control strategy for the wind turbine pitch system is as follows:

[0029] When the main control system of the wind turbine recognizes the typhoon condition, it will switch to the typhoon-resistant mode and trigger the pitch system to shut down the turbine. The pitch system will retract the three blades to the 91-degree shutdown position, and then within a preset time, it will pitch the three blades to the -90-degree typhoon-resistant position and engage the pitch brake and hold brake to stop the turbine.

[0030] The mechanism of the above-mentioned typhoon-resistant mode control strategy is as follows: when the extreme wind speed exceeds the theoretical design limit of the wind turbine generator set, the blades are pitched to the -90° typhoon-resistant position and then the pitch brake is engaged. After stopping the machine in this way, it can be ensured that the actual load on the wind turbine generator set does not exceed the limit design load of the wind turbine generator set when the typhoon arrives.

[0031] In some embodiments, after the main control system of the wind turbine identifies the typhoon condition by judging wind speed and direction, it disconnects the safety chain from the main control system to the pitch system and transmits a software emergency stop signal (EFC signal) to the pitch system via slip ring communication, informing the pitch system to shut down immediately. The mechanism of this step is as follows: When a typhoon arrives, the wind turbine detects that the wind speed exceeds the theoretically designed limit. The main control system will determine according to a preset program that the wind turbine should shut down urgently; therefore, the safety chain from the main control system (nacelle) to the pitch system must be disconnected. After the pitch system detects the disconnection of the safety chain hardware signal (24V) from the main control system, or receives the software emergency stop signal, it will immediately execute an emergency stop. The safety chain is disconnected at this time because the wind turbine needs the pitch system to shut down quickly after identifying the typhoon condition.

[0032] In some embodiments, upon receiving a "software emergency stop signal" or "safety chain hardware signal disconnection" from the main control system, the pitch system state machine switches from normal operation to emergency stop state, and retracts the three blades to 91° at a predetermined speed according to the program. 91° is the normal emergency stop position for wind turbine generators. The predetermined speed for retracting the blades is a safe stop speed calculated based on the blade length, power rating, and wind zone where the wind turbine generator is located, and is generally in the range of 2.5°-5° / s.

[0033] In some embodiments, after the pitch system has stopped to a safe stopping position, the master control system sends an "enter typhoon stopping mode" flag to the pitch system, and sends a "reset signal," "close safety chain," and "target position -90°" to the pitch system, switching the pitch system state machine to "typhoon-resistant state." The safety chain is closed because a typhoon is approaching, and the pitch system is already stopped at its normal stopping position; however, to withstand the typhoon, it needs to stop at a different position. The pitch system needs to receive position control commands from the master control system to perform pitch operations, at which point the safety chain must be closed; otherwise, the pitch system cannot operate.

[0034] After receiving the "Enter Typhoon Shutdown Mode" flag and "Target Position -90°" from the main control system, the pitch system will move the blades out of the current shutdown position and pitch the blades to the -90° typhoon-resistant position; then it will engage the pitch brake and hold the brake to stop the machine, and at the same time, the pitch system will transmit the "Safe Position Reached" flag to the main control system.

[0035] In some embodiments, the pitch system pitches the three blades to a typhoon-resistant position of -90° within a preset time. Specifically, the preset time is 10 seconds, and the three blades pitch to -90° sequentially at a pitch speed of -2° / s. After one blade completes its action, the next blade takes a 3-second interval before starting its action.

[0036] In some embodiments, a limit switch is added at a -90° position to limit the blade position, which can more safely protect the wind turbine generator from safety accidents under typhoon conditions.

[0037] The following is an explanation of the state machine of the pitch system mentioned above:

[0038] The pitch system state machine is a state transition mechanism within the pitch system program. Different operating states are subject to strict conditions; switching can only occur after these conditions are met. It is a software design scheme to protect the pitch system's safety. For example... Figure 2 As shown, the condition constraints of the pitch system state machine under different operating states include:

[0039] T2: When the hardware safety chain signal is broken, or the main control system sends a software emergency stop signal to the pitch system, or the pitch system itself malfunctions, or the communication between the pitch system and the main control system times out, the pitch system state machine switches from automatic operation mode to emergency stop mode.

[0040] T5: When the main control system sends the "Enter Typhoon Shutdown Mode" flag to the pitch system, and the pitch system itself is fault-free, the hardware safety chain signal is normal, and the pitch system receives the reset command from the main control system, the pitch system state machine switches from emergency stop mode to typhoon resistance mode.

[0041] T6: When the main control system sends an "exit typhoon mode" flag to the pitch system, the hardware safety chain signal is broken, the pitch system itself malfunctions, the main control system sends a software emergency stop signal to the pitch system, and the communication between the pitch system and the main control system times out, the pitch system state machine switches from typhoon mode to emergency stop mode.

[0042] T3: When the main control system sends the target positions of the three blades to the pitch system, all of which are between 0° and 89°, and the pitch system receives the reset command from the main control system, and the communication between the pitch system and the main control system is normal, and the pitch system itself is fault-free, the pitch system state machine switches from emergency stop mode to automatic operation mode.

[0043] By adopting the above technical solution, the control strategy of the pitch system was adjusted. A "typhoon resistance mode" was added to the pitch system state machine. This operating condition was redefined, and the switching logic of the pitch system state machine was redesigned to ensure that when a typhoon arrives, the pitch system can obey the master control command to stop at the -90° typhoon resistance position, which can meet the typhoon resistance requirements of the entire wind turbine generator set. After the typhoon, it can normally move out of the stop position and return to the stop angle under non-typhoon operating conditions.

[0044] The pitch control system, while ensuring its own safety, works in conjunction with the entire turbine to complete the typhoon-resistant strategy response, reducing the operational risks of the wind turbine in typhoon conditions and improving the reliability of the wind turbine.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A typhoon-resistant control strategy for a wind turbine pitch control system, characterized in that, include: When the main control system of the wind turbine recognizes the outward wind condition, it triggers the pitch system to shut down the turbine and retracts the three blades to the 91-degree shutdown position. When the three blades are retracted to the 91-degree stop position, the main control system sends a flag to the pitch system to enter the typhoon stop mode, and sends a reset signal, closed safety chain and target position -90° to the pitch system, switching the pitch system state machine to typhoon resistance mode. Within a preset time, the three blades will be adjusted to a typhoon-resistant position of -90°. Engage the pitch brake and hold brake to stop the engine.

2. The typhoon-resistant mode control strategy for the wind turbine pitch system according to claim 1, characterized in that, When the pitch system state machine switches to typhoon-resistant mode, the pitch system will move the blades out of the current stop position according to the target position of -90°, and will pitch the blades to the -90° typhoon-resistant position within a preset time.

3. The typhoon-resistant mode control strategy for the wind turbine pitch system according to claim 2, characterized in that, The preset time is 10 seconds. The three blades change the pitch to -90° in sequence at a pitching speed of -2° / s. After one blade completes its action, there is a 3-second interval before the next blade begins its action.

4. The typhoon-resistant mode control strategy for the wind turbine pitch system according to claim 1, characterized in that, A limit switch is provided at a position of -90°.

5. A state machine switching method for a wind turbine pitch system, characterized in that, Based on the typhoon-resistant mode control strategy of the wind turbine pitch system according to claim 1, the state machine is switched in mode, and the state machine includes automatic operation mode, emergency stop mode and typhoon-resistant mode.

6. The state machine switching method for a wind turbine pitch system according to claim 5, characterized in that, When the hardware safety chain signal is broken, or the main control system sends a software emergency stop signal to the pitch system, or the pitch system itself malfunctions, or the communication between the pitch system and the main control system times out, the pitch system state machine switches from automatic operation mode to emergency stop mode.

7. The state machine switching method for a wind turbine pitch system according to claim 5, characterized in that, When the main control system sends a "Enter Typhoon Shutdown Mode" flag to the pitch system, and the pitch system itself is fault-free, the hardware safety chain signal is normal, and the pitch system receives a reset command from the main control system, the pitch system state machine switches from emergency stop mode to typhoon resistance mode.

8. The state machine switching method for a wind turbine pitch system according to claim 5, characterized in that, When the main control system sends an "exit typhoon mode" flag to the pitch system, the hardware safety chain signal is broken, the pitch system itself malfunctions, the main control system sends a software emergency stop signal to the pitch system, and the communication between the pitch system and the main control system times out, the pitch system state machine switches from typhoon mode to emergency stop mode.

9. The state machine switching method for a wind turbine pitch system according to claim 5, characterized in that, When the main control system sends the target positions of the three blades to the pitch system, all of which are between 0° and 89°, and the pitch system receives the reset command from the main control system, and the communication between the pitch system and the main control system is normal, and the pitch system itself is fault-free, the pitch system state machine switches from emergency stop mode to automatic operation mode.

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