Multi-drive variable pitch control method and device, blade variable pitch system and computer readable storage medium

Abstract

The invention provides a multi-drive variable-pitch control method and device, a blade variable-pitch system and a computer readable storage medium, relates to the technical field of wind power control, and can obtain a variable-pitch control state when the blade variable-pitch system enters a working condition above a rated wind speed and judge whether the system enters the state for the first time. If entering is carried out for the first time, any driver is started to execute variable pitch operation; and if the driver does not enter for the first time, starting the driver which is not started before or has the least accumulated starting times to execute the variable pitch operation. Namely, in each variable pitch task, only one driver is selected to independently undertake operation instead of starting a plurality of drivers at the same time. Through the control strategy, each variable pitch action is independently completed by a single driver, the problems of output jitter, current oscillation, unstable control loop and the like caused by dynamic coupling when multiple drivers cooperatively work are effectively avoided, and the response stability, the control precision and the operation reliability of the variable pitch system are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of wind power control technology, and more specifically, to a multi-drive pitch control method, device, blade pitch system, and computer-readable storage medium. Background Technology

[0002] A multi-drive pitch control system refers to a wind turbine where each blade is equipped with two or more drives that coordinate the pitch control of the same blade to achieve precise angle adjustment. Currently, most mainstream control schemes adopt a master-slave control mode, where one drive acts as the master drive, receiving commands from the master control system and leading the pitch control operation, while the other drives act as slave drives, synchronously controlling the torque, current, or position signals of the master drive.

[0003] However, the inventors discovered that in large wind turbine generator sets, the pitch system often faces high-frequency alternating control commands and periodically fluctuating external aerodynamic loads. Under these conditions, the aforementioned master-slave control strategy is prone to problems such as output jitter and control loop oscillations due to dynamic coupling between multiple drives, affecting the stability and reliability of the system operation. Summary of the Invention

[0004] The present invention aims to provide a multi-drive pitch control method, device, blade pitch system, and computer-readable storage medium, which can start a single drive to perform operation according to a rotation strategy when entering a pitch control state above the rated wind speed, thereby avoiding dynamic coupling of multiple drives and improving system stability and reliability.

[0005] The embodiments of the present invention can be implemented as follows: In a first aspect, the present invention provides a multi-drive pitch control method applied to the blade pitch system of a wind turbine generator set, the method comprising: The blade pitch system is brought into pitch control mode above the rated wind speed. Determine whether the blade pitch system has entered pitch control state for the first time; If so, start any drive to perform pitch operation; If not, then according to the preset rotation strategy, the drive that has not been used before or has the fewest cumulative uses will be activated to perform the pitch operation.

[0006] In an optional implementation, the method further includes: Get the first drive current of the currently started driver; Determine whether the first drive current is greater than the first preset threshold; If so, then obtain the first duration during which the first drive current exceeds the first preset threshold; Determine whether the first duration has reached the first preset time; If so, then according to the rotation strategy, one or more idle drives are started to collaboratively perform the pitch operation.

[0007] In an optional implementation, the method further includes: Obtain the second drive current of all started drivers; Determine whether all second drive currents are less than the second preset threshold. If so, then obtain the second duration during which all started drivers are below the second preset threshold; Determine whether the second duration has reached the second preset time; If so, then the driver that started later will be shut down.

[0008] In an optional implementation, the step of initiating one or more idle drives to collaboratively perform pitch operation includes: Start one or more idle drives with a preset angular acceleration, increase their speed to the target speed, and then coordinate with other running drives to perform pitch control after reaching the target speed.

[0009] In an optional implementation, the preset angular acceleration α has a range of -5deg / s² < α < 5deg / s².

[0010] In an optional implementation, the rotation strategy is characterized as follows: rotating sequentially from right to left or from right to left according to the preset arrangement order of the drivers.

[0011] In an optional implementation, the step of obtaining the blade pitch system into a pitch control state above the rated wind speed includes: Get the current pitch speed of the wind turbine generator; Determine if the pitch speed is not zero; If so, the blade pitch system is determined to have entered a pitch control state above the rated wind speed.

[0012] In a second aspect, the present invention provides a multi-drive pitch control device, the device comprising: The acquisition module is used to acquire information about the blade pitch control system entering a pitch control state above the rated wind speed. The judgment module is used to determine whether the blade pitch system has entered the pitch control state for the first time.

[0013] The control module is used to start any drive to perform pitch operation, and to start the drive that has not been used before or has the fewest cumulative uses to perform pitch operation according to a preset rotation strategy.

[0014] Thirdly, the present invention provides a blade pitch control system, comprising: one or more processors and a memory; the memory is used to store computer program code, the computer program code including a computer program; when one or more processors execute the computer program, the processors perform a multi-drive pitch control method as described in any of the foregoing embodiments.

[0015] Fourthly, the present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the multi-drive pitch control method as described in any of the foregoing embodiments.

[0016] The beneficial effects of the multi-drive pitch control method, apparatus, blade pitch system, and computer-readable storage medium provided in the embodiments of the present invention include: This invention provides a multi-drive pitch control method, apparatus, blade pitch system, and computer-readable storage medium. It can acquire the pitch control state of the blade pitch system when it enters a condition above rated wind speed and determine whether the system is entering this state for the first time. If it is the first time entering this state, any one of the drives is activated to perform the pitch operation; if it is not the first time entering this state, the drive that has not been activated before or has the fewest cumulative activations is activated to perform the pitch operation. That is, in each pitch task, only one drive is selected to independently perform the operation, rather than activating multiple drives simultaneously. Through this control strategy, each pitch action is completed independently by a single drive, effectively avoiding problems such as output jitter, current oscillation, and control loop instability caused by dynamic coupling when multiple drives work together, significantly improving the response stability, control accuracy, and operational reliability of the pitch system. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic block diagram of the blade pitch system provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the blade pitch system provided in an embodiment of the present invention; Figure 3 A flowchart illustrating the multi-drive pitch control method provided in an embodiment of the present invention; Figure 4 This is another schematic flowchart of the multi-drive pitch control method provided in an embodiment of the present invention; Figure 5This is a schematic block diagram of the structure of the multi-drive pitch control device provided in an embodiment of the present invention.

[0019] Icons: 10-Blade pitch control system; 110-Memory; 120-Processor; 010-Wind turbine main control unit; 030-Blade pitch control unit; 031-Pitch bearing; 033-Driver; 035-Drive motor; 037-Gearbox; 20-Multi-drive pitch control device; 210-Acquisition module; 220-Judgment module; 230-Control module. Detailed Implementation

[0020] In related technologies, multi-drive pitch control systems adopt a master-slave control mode, which is prone to output jitter and control loop oscillation due to dynamic coupling between the drives, affecting the stability and reliability of the system.

[0021] To address the aforementioned issues, this invention provides a multi-drive pitch control method, device, blade pitch system, and computer-readable storage medium. When entering a pitch control state above rated wind speed, a single drive is activated according to a rotation strategy to perform operations, avoiding dynamic coupling of multiple drives and improving system stability and reliability.

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0024] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0025] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed, they are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0026] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0027] It should be noted that, where there is no conflict, the features in the embodiments of the present invention can be combined with each other.

[0028] The following detailed description, through embodiments and in conjunction with the accompanying drawings, details the overall structure, working principle, and technical effects of the blade pitch system provided by the present invention, as well as the detailed steps, implementation principles, and technical effects of the supporting multi-drive pitch control method.

[0029] Please see Figure 1 This invention provides a multi-drive pitch control method and a multi-drive pitch control device 20, applied to the blade pitch system 10 of a wind turbine generator set. The blade pitch system 10 may include a memory 110 and one or more processors 120.

[0030] The memory 110 and processor 120 are directly or indirectly connected to each other to enable data transmission or interaction. For example, these components can be connected to each other via one or more communication buses or signal lines. The blade pitch control system includes at least one software function module that can be stored in the memory 110 or embedded in the operating system (OS) of a server in the form of software or firmware. The processor 120 is used to execute the executable modules stored in the memory 110, such as the software function modules and computer programs included in the blade pitch control system.

[0031] The memory 110 may be, but is not limited to, random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), etc. The memory 110 stores computer program code, which includes computer instructions. When one or more processors 120 execute the computer instructions, the processors 120 execute the multi-drive pitch control method.

[0032] like Figure 2As shown, the blade pitch system 10 includes a wind turbine main control unit 010 and multiple blade pitch control units 030. The wind turbine main control unit 010 is communicatively connected to each blade pitch control unit 030, and drives a corresponding drive motor 035 via each blade pitch control unit 030 to complete the corresponding blade pitch control. Each blade pitch control unit 030 includes a pitch bearing 031, at least two drivers 033, and a drive motor 035 corresponding to each driver 033. All drive motors 035 are driven by the pitch bearing 031 via a transmission mechanism. Optionally, the transmission mechanism can be a gearbox 037. In this embodiment, the aforementioned processor 120 is communicatively connected to the drivers 033.

[0033] Please see Figure 3 The multi-drive pitch control method provided in this embodiment may include the following steps: Step S210: Obtain the blade pitch system 10 into a pitch control state above the rated wind speed.

[0034] Before executing step S210, after the blade pitch system 10 is powered on and started, the historical activation records of each drive 033 are cleared to initialize the status information of the drive 033.

[0035] Step S300: Determine whether the blade pitch system 10 has entered the pitch control state for the first time.

[0036] In step S300, specifically, if no pitching action has been performed since the system was powered on, it is determined to be the first entry; otherwise, it is a non-first entry.

[0037] Step S310: If the blade pitch system 10 is entering the pitch control state for the first time, then start any drive 033 to perform the pitch operation.

[0038] Step S330: If the blade pitch system 10 is not entering the pitch control state for the first time, start the driver 033 that has not been used before or has the fewest cumulative activations to perform the pitch operation.

[0039] The aforementioned mechanism helps to ensure that each drive unit 033 has an equal opportunity to operate during its operating cycle, effectively avoiding excessive wear caused by frequent and prolonged use of individual drive units 033, and balancing the load distribution among drive units. Simultaneously, this strategy can alleviate the problem of uneven local wear caused by continuous force on the same gear tooth surface, reduce the occurrence of abnormal operating conditions such as off-center load on the transmission mechanism and pitch reverse drag, thereby improving the operational smoothness, control stability, and overall reliability of the pitch system.

[0040] Furthermore, it is important to emphasize that during any pitch control operation, only one drive 033 is active, while the remaining unselected drives 033 remain idle and do not participate in the current pitch control action. This control mechanism ensures that each pitch control task is undertaken independently by a single drive 033, effectively avoiding problems such as dynamic coupling, output interference, and current oscillations caused by multiple drives 033 operating simultaneously.

[0041] To further and effectively avoid premature wear or fatigue failure of individual drives 033 due to frequent use, the rotation strategy is characterized as follows: according to the preset arrangement order of the drives 033, they are rotated sequentially from right to left. When the leftmost drive 033 is rotated, the rotation returns to the rightmost drive 033 in the next operating cycle to continue rotating; or, the rotation is performed sequentially from left to right. When the rightmost blade pitch control unit 030 is rotated, the rotation returns to the leftmost blade pitch control unit 030 in the next operating cycle to continue rotating.

[0042] Specifically, please refer to [link / reference] again. Figure 2 In one embodiment, each blade pitch control unit 030 is equipped with three drivers 033, which are labeled as Flag1, Flag2 and Flag3 from left to right. The controller uses a binary label to indicate the operating status of each driver 033: it is labeled as "1" when the driver 033 is in the start state and as "0" when it is in the idle state.

[0043] If a left-to-right rotation strategy is adopted, in the initial round, the leftmost Flag1 is activated first, and the states of the three flags are 1, 0, and 0 respectively. When the pitch control state above the rated wind speed is entered again, the middle Flag2 is activated and the state is updated to 0, 1, and 0. When the pitch is adjusted again, the rightmost Flag3 is activated and the state becomes 0, 0, and 1. After completing one cycle, the next pitch cycle returns to the leftmost Flag1 and the state is restored to 1, 0, and 0, thus achieving a cyclical sequential rotation.

[0044] Furthermore, please refer again. Figure 3 The steps for obtaining the blade pitch system 10 to enter a pitch control state above the rated wind speed include: Step S100: Obtain the current pitch speed of the wind turbine generator set.

[0045] In step S100, it should be noted that the current pitch speed is generated by the wind turbine main control unit 010 after comprehensive calculation based on the real-time wind speed, the power of the generator drive motor 035, the wind turbine speed feedback and the actual position signal of the blades, and can be sent to each blade pitch control unit 030 through the communication bus.

[0046] Step S200: Determine whether the pitch speed is not zero.

[0047] In step S210, if the pitch speed is not zero (0deg / s), then the blade pitch system 10 enters a pitch control state above the rated wind speed.

[0048] In step S210, the wind turbine needs to actively adjust the blade angle to maintain stable operation near the rated power. Correspondingly, if the current pitch speed is zero or the pitch speed is zero or remains zero for a certain duration (e.g., 0.5 seconds), it is determined that the blade pitch system 10 is operating below the rated wind speed or in a standby state. At this time, no active pitch adjustment is required, and each actuator 033 enters standby mode, waiting for the pitch demand to be triggered.

[0049] Further, please refer to Figure 4 After step S300, the method further includes: Step S400: Obtain the first drive current of the currently started driver 033.

[0050] In step S400, the system collects the output current value of the driver 033 (i.e. the unit selected as the action driver 033) that is currently in operation in real time, as a key feedback signal reflecting its actual load level, for subsequent overload judgment.

[0051] Step S500: Determine whether the first drive current is greater than the first preset threshold.

[0052] In step S500, the acquired first drive current is compared with a first preset threshold to identify whether there is an overload trend. The first preset threshold is slightly higher than the current level under normal full-load conditions, specifically set to 1.05 times the rated current of the driver 033.

[0053] Step S510: If the first drive current is greater than the first preset threshold, then obtain the first duration for which the first drive current exceeds the first preset threshold.

[0054] In step S510, if the first drive current does not exceed the first preset threshold, the current single drive 033 operation mode is maintained; if it does exceed the threshold, the duration of the current overload state is recorded to assess the severity of the overload and ensure that the intervention mechanism is triggered only when the load actually exceeds the single drive's sustainable bearing capacity.

[0055] Step S600: Determine whether the first duration has reached the first preset time.

[0056] In step S600, in one embodiment, the first preset time is 0.5 seconds. When the time during which the first drive current continuously exceeds the first preset threshold reaches or exceeds the set value, it is determined to be a valid overload event, triggering the subsequent coordinated control process.

[0057] Step S610: If the first duration reaches the first preset time, then according to the rotation strategy, one or more drivers 033 in the idle state are started to perform pitch operation in coordination.

[0058] In step S610, when the first drive current continuously exceeds 1.05 times the rated current for 0.5 seconds or more, the system determines that the current single drive motor 035 can no longer reliably bear the external aerodynamic load, and the backup drive capability needs to be activated to ensure the continuity and stability of the pitch function. At this time, the control system, according to the preset rotation strategy, sequentially wakes up one or more idle backup drives 033 and puts them into operation, realizing the coordinated output of multiple drives 033.

[0059] For example, if the states of Flag1, Flag2, and Flag3 are 1, 0, and 0 respectively, it indicates that only the driver 033 corresponding to Flag1 is in the start-up state and bears the entire pitch load. When it is detected that the current of the driver 033 continuously exceeds 1.05 times its rated current for 0.5 seconds, it indicates that the current single driver 033 can hardly reliably bear the external load. At this time, the system will start the drivers 033 corresponding to Flag2 and Flag3 that are in the idle state in sequence according to the preset rotation strategy, so that they can participate in the pitch operation together and share the load.

[0060] Furthermore, to prevent a step shock in speed or drive current of the newly engaged drive 033, the step of starting one or more idle drives 033 to perform pitch operation in coordination includes: starting one or more idle drives 033 with a preset angular acceleration to increase their speed to the target speed, and then performing pitch operation in coordination with other running drives 033 after reaching the target speed.

[0061] Furthermore, the preset angular acceleration α has a range of -5 deg / s² < α < 5 deg / s². It should be noted that this range effectively suppresses dynamic disturbances during acceleration while ensuring pitch response speed, thereby improving the system's stability and reliability. Optionally, the preset angular acceleration α is ±3 deg / s².

[0062] Please refer to it again. Figure 4 After step S610, the method further includes: Step S700: Obtain the second drive current of all started drivers 033.

[0063] In step S700, the system collects the output current values ​​of all drivers 033 currently in operation (including the initial driver 033 and the standby driver 033 that has been put into operation) in real time.

[0064] Step S800: Determine whether all second drive currents are less than the second preset threshold.

[0065] In step S800, the second preset threshold can be set to 0.9 times the rated current of driver 033. This comparison determines whether each drive unit has been removed from the high-load condition.

[0066] Step S810: If all second drive currents are less than the first preset threshold, then obtain the second duration during which all started drivers 033 are below the second preset threshold.

[0067] In step S810, when the current of all enabled drivers 033 drops below 0.9 times the rated current, the system starts timing and records the duration of the low current state to determine the stability of the load drop.

[0068] Step S900: Determine whether the second duration has reached the second preset time.

[0069] In step S900, the second preset time is 1 second. When the current of all drivers 033 remains below the second preset threshold for a period of time that reaches or exceeds the set value, it is determined that the system has entered a stable operating condition for continuous single-drive operation.

[0070] In step S910, if the second duration reaches the second preset time, then the driver 033 that was started later will be shut down.

[0071] In step S910, if the drive current of all engaged drivers 033 remains less than 0.9 times the rated current for 1 second, the control system shuts down the subsequently activated backup drivers 033 in reverse order of activation, ultimately retaining the initially selected primary driver 033 to continue operating, while the remaining drivers 033 return to idle status, awaiting the next rotation. That is, the drivers 033 corresponding to Flag2 and Flag3 are sequentially switched to idle status, restoring the single-drive operation mode of the driver 033 corresponding to Flag1.

[0072] In summary, this invention provides a multi-drive pitch control method that can acquire the pitch control state of the blade pitch system 10 when it enters a condition above the rated wind speed and determine whether the system is entering this state for the first time. If it is the first time entering this state, any one of the drives 033 is activated to perform the pitch operation; if it is not the first time entering this state, the drive 033 that has not been activated before or has the fewest cumulative activations is activated to perform the pitch operation. That is, in each pitch task, only one drive 033 is selected to independently undertake the operation, rather than activating multiple drives 033 simultaneously. Through this control strategy, each pitch action is completed independently by a single drive 033, effectively avoiding problems such as output jitter, current oscillation, and control loop instability caused by dynamic coupling when multiple drives 033 work together, significantly improving the response stability, control accuracy, and operational reliability of the pitch system.

[0073] Please see Figure 5 To execute the possible steps of the multi-drive pitch control method provided in the above embodiments, this embodiment of the invention provides a multi-drive pitch control device 20, applied to the blade pitch system 10, for executing the above-described multi-drive pitch control method. It should be noted that the basic principle and technical effects of the multi-drive pitch control device 20 provided in this embodiment are basically the same as those in the above embodiments. For the sake of brevity, any parts not mentioned in this embodiment can be referred to the corresponding content in the above embodiments.

[0074] The multi-drive pitch control device 20 provided in this embodiment may include an acquisition module 210, a judgment module 220, and a control module 230.

[0075] The acquisition module 210 is used to acquire information about the blade pitch system 10 entering a pitch control state above the rated wind speed. The judgment module 220 is used to determine whether the blade pitch system 10 is entering the pitch control state for the first time. The control module 230 is used to start any one of the actuators 033 to perform pitch operation, and is used to start the actuator 033 that has not been used before or has the fewest cumulative uses to perform pitch operation according to a preset rotation strategy.

[0076] In addition, some embodiments of the present invention also provide a computer-readable storage medium storing a computer program that, when executed by the processor 120, implements the multi-drive pitch control method provided in any of the above embodiments.

[0077] In addition, some embodiments of the present invention also provide a blade pitch system 10, including one or more processors 120 and a memory 110. The memory 110 is used to store computer program code, which includes a computer program. When one or more processors 120 execute the computer program, the processors 120 perform the multi-drive pitch control method provided in any of the above embodiments.

[0078] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can also be implemented in other ways. The apparatus embodiments described above are merely illustrative; for example, the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code, which contains one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0079] In addition, the functional modules in the various embodiments of the present invention can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0080] If the functionality is implemented as a software module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0081] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A multi-drive variable pitch control method applied to a blade pitch system of a wind turbine generator set, characterized in that, The method comprises: acquiring that the blade pitch system enters a pitch control state above the rated wind speed; determining whether the blade pitch system enters the pitch control state for the first time; if yes, starting any drive to perform the pitch operation; if no, according to a preset rotation strategy, starting the drive which has not been started before or has the least cumulative starting times to perform the pitch operation.

2. The multi-drive variable pitch control method of claim 1, wherein, The method further comprises: acquiring a first drive current of the currently started drive; determining whether the first drive current is greater than a first preset threshold; if yes, acquiring a first duration in which the first drive current exceeds the first preset threshold; determining whether the first duration reaches a first preset time; if yes, according to the rotation strategy, starting one or more drives in an idle state to perform the pitch operation.

3. The multi-drive variable pitch control method of claim 2, wherein, The method further comprises: acquiring second drive currents of all the started drives; determining whether all the second drive currents are less than a second preset threshold; if yes, acquiring a second duration in which all the started drives are less than the second preset threshold; determining whether the second duration reaches a second preset time; if yes, stopping the drive started later.

4. The multi-drive variable pitch control method of claim 2, wherein, The step of starting one or more drives in an idle state to perform the pitch operation comprises: starting one or more drives in an idle state at a preset angular acceleration to increase the rotational speed to a target rotational speed, and performing the pitch operation with other drives in operation after reaching the target rotational speed.

5. The multi-drive variable pitch control method of claim 4, wherein, The preset angular acceleration α is in a range of -5 deg / s² < α < 5 deg / s².

6. The multi-drive variable pitch control method of claim 1, wherein, The rotation strategy is characterized by rotating from right to left or from right to left according to a preset arrangement order of the drives.

7. The multi-drive variable pitch control method of claim 1, wherein, The step of acquiring that the blade pitch system enters a pitch control state above the rated wind speed comprises: acquiring a current pitch speed of the wind turbine generator; determining whether the pitch speed is not zero; if yes, determining that the blade pitch system enters the pitch control state above the rated wind speed.

8. A multi-drive variable pitch control apparatus characterized by, The device comprises: an acquisition module for acquiring that the blade pitch system enters a pitch control state above the rated wind speed; a determination module for determining whether the blade pitch system enters the pitch control state for the first time; a control module for starting any drive to perform the pitch operation, and for starting the drive which has not been started before or has the least cumulative starting times to perform the pitch operation according to a preset rotation strategy.

9. A blade pitch system, characterized by comprises: one or more processors and a memory; the memory is used to store computer program codes, the computer program codes comprise a computer program; when the one or more processors execute the computer program, the processor performs the multi-drive pitch control method according to any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, the computer program comprising instructions that, when executed by a computer, cause the computer to perform the method of any one of claims 1 to 9. The computer program is executed by the processor to implement the multi-drive pitch control method according to any one of claims 1 to 7.

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