Pitch control system for wind turbines

Abstract

A system for pitch control of wind turbines, characterized in that it comprises: a pitch motor (100); and a control module (200), a drive module (300) and an energy storage and supply module (400) provided on the pitch motor (100), wherein the control module (200) sends a control signal and transmits the control signal to the drive module (300); wherein the drive module (300) converts the control signal into a drive signal which is used to drive the pitch motor (100) for rotation and to regulate the rotor blade rudder angle; wherein the energy storage and supply module (400) is used to store and release energy, the energy being used to bring the rotor blades into the driving position.

Description

TECHNICAL AREA

[0001] The present invention relates to the field of pitch control technology for wind turbines, in particular a system for pitch control of wind turbines. STATE OF THE ART

[0002] Wind energy, as a clean and renewable energy source, has already seen widespread application and development. A wind turbine system mainly consists of the tower, the rotor, the pitch motor, etc. The pitch motor is responsible for controlling the angle of the rotor to utilize wind energy as efficiently as possible.

[0003] Currently, common pitch motors for wind turbines typically consist of a separate controller, a drive unit, and an energy storage device (such as a supercapacitor). The controller is responsible for monitoring parameters such as wind speed and direction and controls the motor's rotation and blade pitch angle according to predefined algorithms. The drive unit is responsible for powering and controlling the motor to perform precise pitch operations. Energy storage systems, on the other hand, can provide additional power and increase the system's stability and reliability.

[0004] However, existing pitch motors for wind turbines have several problems. First, the separate design and installation of the controller, drive, and energy storage unit results in a relatively complex system structure and higher installation and maintenance costs. Second, the connection and communication between independent components presents certain technical challenges, which could affect the system's response time and stability. Furthermore, the precision of the existing preset algorithms for controlling and regulating the motor is insufficient. CONTENT OF THE PRESENT INVENTION

[0005] The purpose of this section is to summarize some aspects of the embodiments of the present invention and to briefly present some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of the application, so as not to obscure the purpose of this section, the abstract, and the title. However, these simplifications or omissions must not be used to limit the scope of this invention.

[0006] In view of the aforementioned and / or existing problems in the existing technology, the present invention was developed.

[0007] Therefore, a first purpose of the present invention is to provide a pitch control system for wind turbines that can compactly integrate several independent components on the pitch motor in order to realize a space-saving and highly integrated device.

[0008] To solve the aforementioned technical problem, the present invention offers the following technical solution: A pitch control system for wind turbines, comprising: a pitch motor; a control module arranged on the pitch motor, a drive module, and an energy storage and supply module; wherein the control module sends a control signal and transmits the control signal to the drive module, wherein the drive module converts the control signal into a drive signal used to drive the pitch motor for rotation and to regulate the rotor blade rudder angle; wherein the energy storage and supply module is used to store and release energy, the energy being used to bring the rotor blades into the travel position.

[0009] In a preferred embodiment of the pitch control system for wind turbines according to the present invention, the control module, the drive module and the energy storage and supply module are detachably mounted on a housing of the pitch motor, and wherein the control module, the drive module and the energy storage and supply module can enclose the pitch motor.

[0010] In a preferred embodiment of the pitch control system for wind turbines according to the present invention, the control module comprises a main control unit and a position circuit, wherein the main control unit sends a reference position instruction and transmits the reference position instruction to the position circuit, wherein the position circuit compares the reference position instruction with the actual position of the pitch motor and forms position error data from it, as well as amplifying the position error data and generating a speed reference signal.

[0011] In a preferred embodiment of the pitch control system for wind turbines according to the present invention, the drive module comprises a speed circuit, wherein the speed circuit receives a speed reference signal, compares the speed reference signal with the actual speed of the pitch motor, forms speed error data from it and converts this speed error data into a current reference signal, wherein the current reference signal represents a straight-axis current component in the rotating coordinate system.

[0012] In a preferred embodiment of the pitch control system for wind turbines according to the present invention, the drive module further comprises a circuit, wherein the circuit receives a current reference signal and compares the current reference signal with the actual straight-axis current of the pitch motor, forms the current error data from this and converts the current error data into voltage commands in the rotating coordinate system.

[0013] As a preferred embodiment of the pitch control system for wind turbines according to the present invention, it further comprises a park transformation module, wherein the park transformation module receives voltage commands in a rotating coordinate system and converts the voltage commands in the rotating coordinate system into voltage commands in a two-phase stationary coordinate system.

[0014] As a preferred embodiment of the pitch control system for wind turbines according to the present invention, it further comprises an SVPWM module, wherein the SVPWM module receives voltage commands in a two-phase stationary coordinate system and generates PWM signals from them, and wherein the SVPWM module then converts the direct current into a three-phase alternating current according to the PWM signals and drives the pitch motor.

[0015] In a preferred embodiment of the pitch control system for wind turbines according to the present invention, it further comprises a speed and position feedback module, wherein the speed and position feedback module is used to collect actual speed signals and actual position signals of the pitch motor and to transmit the actual speed signals and actual position signals to the control module.

[0016] In a preferred embodiment of the pitch control system for wind turbines according to the present invention, it further comprises a Clark transformation module and an inverse park transformation module, wherein the Clark transformation module receives the three-phase current signal of the pitch motor and converts it into the current signal of the two-phase stationary coordinate system; wherein the inverse park transformation module receives the current signals of the two-phase stationary coordinate system and converts them into current signals of the rotating coordinate system and returns the current signals of the rotating coordinate system to the drive module;

[0017] A second objective of the invention is to provide a method for pitch control for wind turbines that can react quickly to changes in external commands through a layered control strategy while maintaining stable operation of the motor in order to achieve the rotation of the pitch motor and precise control of the blade pitch angle, thus meeting the operational requirements of wind turbines.

[0018] To solve the aforementioned technical problem, the present invention offers the following technical solution: A method for pitch control of wind turbines, comprising: issuing a reference position instruction; comparing the reference position instruction with the actual position of the pitch motor and generating a speed reference signal; comparing the speed reference signal with the actual speed of the pitch motor and generating a current reference signal; comparing the current reference signal with the actual straight-axis current and generating voltage commands in the rotating coordinate system; converting the voltage commands of the rotating coordinate system into voltage commands of the two-phase stationary coordinate system; generating PWM signals from the voltage commands; converting direct current to three-phase alternating current based on the PWM signals and driving the pitch motor.

[0019] The advantageous effect of the present invention lies in the fact that several independent components are tightly integrated into the pitch motor to realize compact and highly integrated devices; a layered control strategy allows for rapid response to changes in external commands while maintaining stable operation of the motor to achieve rotation of the pitch motor and precise control of the blade pitch angle to meet the operational requirements of wind turbines. BRIEF DESCRIPTION OF THE DRAWING

[0020] To illustrate the technical solutions of the embodiments of the present invention more clearly, the drawings used in the description of these embodiments are briefly presented below. Naturally, the drawings shown in the following description represent only some embodiments of the present invention. Those skilled in the art can derive further drawings from these figures without inventive effort. These drawings include: Fig. Figure 1 shows the structure diagram of the pitch control system for wind turbines. Fig. Figure 2 shows the wiring diagram of the pitch control system for wind turbines. DETAILED DESCRIPTION

[0021] In order to better illustrate the above-mentioned objectives, features and advantages of the present invention, the specific embodiments of the invention will be explained in detail below with reference to the accompanying drawings of the description.

[0022] Many specific details are described below to enable a complete understanding of the present invention. It should be noted, however, that the invention can also be implemented in ways other than those described here. Those skilled in the art can make corresponding extensions while maintaining the essential character of the invention. Therefore, the invention is not subject to the limitations of the specific embodiments disclosed below. Secondly, the present invention is described in detail with reference to schematic diagrams. For better understanding, the detailed descriptions of the embodiments of the invention show that the cross-sectional views depicting the structure of the device are sometimes enlarged to a lesser extent. Furthermore, the schematic diagrams serve only as examples and are not intended to limit the scope of the invention.Furthermore, the three-dimensional spatial dimensions of length, width, and depth should be included in the actual manufacturing process.

[0023] Furthermore, the terms “an embodiment” or “embodiment” used here refer to a specific feature, structure, or property that may be included in at least one embodiment of the present invention. “An embodiment” appearing at different points in this specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments. Example 1

[0024] According to Fig. 1 This is a first embodiment of the present invention, which provides a pitch control system for wind turbines, comprising a pitch motor 100, a control module 200, a drive module 300 and an energy storage and supply module 400.

[0025] Specifically, the pitch motor 100 is responsible for controlling the rotor blade pitch angle in order to optimally utilize wind energy.

[0026] The control module 200, the drive module 300, and the energy storage and supply module 400 are mounted on the pitch motor 100. In this embodiment, the energy storage and supply module 400 is an arc-shaped supercapacitor enclosed below the housing of the pitch motor 100, while the control module 200 and the drive module 300 are positioned above the housing of the pitch motor 100. The separate modules—the control module 200, the drive module 300, and the energy storage and supply module 400—are compactly integrated onto the pitch motor 100 to achieve a space-saving and highly integrated device structure.

[0027] During operation, the control module 200 sends a control signal and transmits the control signal to the drive module 300; the drive module 300 converts the control signal into a drive signal, which is used to drive the pitch motor 100 for rotation and to regulate the rotor blade rudder angle; the energy storage and supply module 400 is used to store and release energy, the energy being used to bring the rotor blades into the driving position. Example 2

[0028] In the second embodiment of the present invention, which is essentially identical to embodiment 1, the difference lies in the energy storage and supply module. The energy storage and supply module 400 consists of a group of lithium-ion batteries, has a higher energy density and a longer cycle life, and is suitable for use in the pitch control system for wind turbines. The lithium-ion battery pack has a modular design and can be easily mounted on the housing of the pitch motor 100 and managed and controlled via the control module 200.

[0029] In this embodiment, the integration methods of the control module 200, the drive module 300, and the energy storage and supply module 400 are identical to embodiment 1. All are tightly integrated onto the pitch motor 100 to achieve a compact design and high integration of the device.

[0030] The advantage of this embodiment is that by using lithium-ion batteries as an energy storage and supply module, the energy density and cycle life of the storage system are increased, while at the same time the compactness and high integration of the system are maintained, which meets the high performance requirements of the system for pitch control of wind turbines on storage devices. Example 3

[0031] Referring to Fig. 1 and Fig. Section 2 describes the third embodiment of the present invention, which is based on the first embodiment.

[0032] Specifically, the control module 200, the drive module 300, and the energy storage and supply module 400 are detachably mounted to a housing of the pitch motor 100, and the control module 200, the drive module 300, and the energy storage and supply module 400 can also enclose the pitch motor 100. The control module 200, the drive module 300, and the energy storage and supply module 400 are installed modularly, which facilitates maintenance and upgrades and increases the system's flexibility.

[0033] Preferably, the control module 200 comprises a main control unit 201 and a position loop 202. The main control unit 201 sends a reference position instruction Position_Ref and transmits it to the position loop 202 Position Loop. The position loop 202 compares the reference position instruction with the actual position Position θ of the pitch motor 100, calculates position error data using a proportional P controller, amplifies the position error data, and generates a speed reference signal Speed_Ref. This speed reference signal represents the target speed that the pitch motor 100 must reach to achieve the target position in time. The proportional P controller is state of the art and is not described further here.

[0034] Preferably, the drive module 300 comprises a speed loop 301, which receives a speed reference signal and compares it with the actual speed of the pitch motor 100. Speed ​​error data is generated by a PI controller and converted into a current reference signal Iq_Ref. This current reference signal represents the straight-axis current component in the rotating coordinate system, which is directly related to the torque of the pitch motor 100. The proportional-integral PI controller is prior art and is not described further here. Preferably, the drive module 300 further comprises a current loop 302, which receives a current reference signal and compares it with the actual straight-axis current of the pitch motor 100. Current error data is generated by another PI controller and converted into voltage commands Vd, Vq in the rotating coordinate system.The hierarchical control of the speed circuit 301 and the current circuit 302 enables precise control of the speed and current of the pitch motor 100, thereby improving the response speed and stability of the system.

[0035] Preferably, the system also includes a Park transformation module 500, which receives voltage commands in the rotating coordinate system and converts them into voltage commands Vα, Vβ in the two-phase stationary coordinate system. This simplifies the control algorithm and improves the control accuracy.

[0036] Furthermore, it includes an SVPWM module 600, which receives the voltage commands in the two-phase stationary coordinate system and generates PWM signals from them.

[0037] The SVPWM module 600 then converts direct current into three-phase alternating current Va, Vb, Vc according to the PWM signals and drives the pitch motor 100. This improves the efficiency and response speed of the pitch motor 100.

[0038] Furthermore, it includes the speed and position feedback module 700, which serves to acquire the actual speed and position signals of the pitch motor 100 and transmit them to the control module 200. The speed and position feedback module 700 acquires the actual speed and position signal, delivers it to the control module 200, forms a closed-loop control system, and improves the control accuracy and stability of the system. It also includes the Clark transform module 800 and the inverse Park transform module 900; the Clark transform module 800 receives the three-phase current signals Ia, Ib, Ic of the pitch motor 100 and converts them into current signals of the two-phase stationary coordinate system Iα, Iβ. The inverse Park transformation module 900 receives the current signals of the two-phase stationary coordinate system, converts them into current signals of the rotating coordinate system Id, Iq and feeds them back to the drive module 300.The Clark Transformer Module 800 and the Inverse Park Transformer Module 900 transform current signals, enabling more precise current control and increasing system stability. The Speed ​​and Position Feedback Module 700 transmits the position signal to the Inverse Park Transformer Module 900, which in turn forwards the position signal to the Park Transformer Module 500. This creates a closed-loop control structure that improves the system's control accuracy and stability. Example 4

[0039] Referring to Fig. 1 and Fig. Section 2 describes the fourth embodiment of the present invention, which is based on embodiments 1 to 3. This example provides a method for pitch control of wind turbines. S100: Issuing a reference position instruction; S200: Comparing the reference position instruction with the actual position of the pitch motor 100 and generating a speed reference signal; S300: Comparing the speed reference signal with the actual speed of the pitch motor and generating a current reference signal; S400: Comparing the current reference signal with the actual straight-axis current and generating voltage commands in the rotating coordinate system; S500: Converting the voltage commands of the rotating coordinate system into voltage commands of the two-phase stationary coordinate system; S600: Generating PWM signals from voltage commands; S700: Converts direct current to three-phase alternating current based on the PWM signals and drives the pitch motor.

[0040] Based on the foregoing, the advantageous effect of the invention is as follows: 1. The separate components - the control module 200, the drive module 300 and the energy storage and supply module 400 - are compactly integrated into the pitch motor 100 to achieve a space-saving and highly integrated device structure. 2. Through a layered control strategy, the system can react quickly to changes in external commands while simultaneously ensuring stable operation of the pitch motor 100. The position circuit 202 provides the final target, the speed circuit 301 ensures that the pitch motor 100 can move at the correct speed, while the current circuit 302 ensures that the pitch motor 100 can generate sufficient torque to achieve this speed. In this way, the rotation of the pitch motor 100 and the blade pitch angle can be precisely controlled to meet the operating requirements of the wind turbine.

[0041] It is important to note that the designs and arrangements of this application, as shown in various exemplary embodiments, are for illustrative purposes only. Although only some embodiments are described in detail in this disclosure, persons skilled in the art will readily recognize, with reference to this disclosure, that many modifications are possible, e.g., changes to the dimensions, measurements, structures, shapes, and proportions of various elements, as well as parameter values ​​such as temperature, pressure, etc., the arrangement of the installation, the use of materials, colors, orientation, etc., without substantially departing from the novel teachings and advantages of the subject matter described in this application.For example, a component depicted as being formed in one piece may consist of several parts or components, the position of elements may be reversed or otherwise changed, and the nature, number, or arrangement of individual elements may be adapted or modified. Therefore, all such changes are intended to be included within the scope of the present invention. The order or sequence of any processes or method steps may be changed or rearranged according to alternative embodiments. In the claims, each "means-plus-function" clause is intended to cover the structures described herein for carrying out the function, including not only structural equivalents but also equivalent structures.Without departing from the scope of the present invention, other substitutions, modifications, changes, and omissions can be made in the design, operating state, and arrangement of the exemplary embodiments. Therefore, the present invention is not limited to specific embodiments but extends to various modifications that are further covered by the appended claims.

[0042] Furthermore, in order to provide a concise description of exemplary embodiments, it is not possible to describe all features of the actual embodiment, i.e., those that are not related to the currently considered best embodiment of the invention or are not relevant for the implementation of the invention.

[0043] It is understandable that during the development of a practical implementation, as with any engineering or design project, a multitude of specific implementation decisions may be made. While such development efforts can be complex and time-consuming, they do not represent excessive experimentation for the average professional benefiting from this disclosure, but rather fall within the conventional tasks of design, manufacturing, and production.

[0044] It should be noted that the exemplary embodiments mentioned above serve only to illustrate the technical concept of the present invention and are not intended to be limiting. Although the invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical concept of the invention can be modified or replaced with an equivalent one without departing from the spirit and scope of the invention. All such modifications fall within the scope of protection of the claims of this invention.

Claims

[1] Pitch control system for wind turbines, characterized by , that it includes: a pitch motor (100); and a control module (200), a drive module (300) and an energy storage and supply module (400) provided on the pitch motor (100), wherein the control module (200) sends a control signal and transmits the control signal to the drive module (300); wherein the drive module (300) converts the control signal into a drive signal which is used to drive the pitch motor (100) for rotation and to regulate the rotor blade rudder angle; wherein the energy storage and supply module (400) is used to store and release energy, the energy being used to bring the rotor blades into the driving position. [2] Pitch control system for wind turbines according to claim 1, characterized by, that the control module (200), the drive module (300) and the energy storage and supply module (400) are detachably mounted on a housing of the pitch motor (100), and wherein the control module (200), the drive module (300) and the energy storage and supply module (400) can enclose the pitch motor (100). [3] Pitch control system for wind turbines according to claim 1 or 2, characterized by , that the control module (200) comprises a main control unit (201) and a position circle (200), wherein the main control unit (201) sends a reference position instruction and transmits the reference position instruction to the position circle (202), wherein the position circle (202) compares the reference position instruction with the actual position of the pitch motor (100) and forms position error data from it, as well as amplifying the position error data and generating a speed reference signal. [4] Pitch control system for wind turbines according to claim 3, characterized by , that the drive module (300) comprises a speed circuit (301) wherein the speed circuit (301) receives a speed reference signal, compares the speed reference signal with the actual speed of the pitch motor (100), forms speed error data from it and converts this speed error data into a current reference signal, wherein the current reference signal represents a straight-axis current component in the rotating coordinate system. [5] Pitch control system for wind turbines according to claim 4, characterized by , that the drive module (300) further comprises a circuit (302) wherein the circuit (302) receives a current reference signal and compares the current reference signal with the actual straight-axis current of the pitch motor (100), forms the current error data from this and converts the current error data into voltage commands in the rotating coordinate system. [6] Pitch control system for wind turbines according to claim 5, characterized by, that it further comprises a Park transformation module (500) wherein the Park transformation module (500) receives voltage commands in a rotating coordinate system and converts the voltage commands in the rotating coordinate system into voltage commands in a two-phase stationary coordinate system. [7] Pitch control system for wind turbines according to claim 6, characterized by , that it further comprises an SVPWM module (600) wherein the SVPWM module (600) receives voltage commands in a two-phase stationary coordinate system and generates PWM signals from them, and wherein the SVPWM module (600) then converts the direct current into a three-phase alternating current according to the PWM signals and drives the pitch motor (100). [8] Pitch control system for wind turbines according to claim 7, characterized by, that it further comprises a speed and position feedback module (700), wherein the speed and position feedback module (700) is used to collect actual speed signals and actual position signals of the pitch motor (100) and to transmit the actual speed signals and actual position signals to the control module (200). [9] Pitch control system for wind turbines according to claim 8, characterized by , that it further comprises a Clark transformation module (800) and an inverse Park transformation module (900); wherein the Clark transformation module (800) receives the three-phase current signal of the pitch motor (100) and converts it into the current signal of the two-phase stationary coordinate system; wherein the inverse Park transformation module (900) receives the current signals of the two-phase stationary coordinate system, converts them into current signals of the rotating coordinate system and returns the current signals of the rotating coordinate system to the drive module (300); wherein the speed and position feedback module (700) also transmits the position signal to the inverse park transformation module (900), which also forwards the position signal to the park transformation module (500).

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