Variable pitch control system based on integrated design
By integrating design and applying silicon carbide semiconductor devices, the problems of multiple connection points and signal delay in electric pitch control systems have been solved, achieving a pitch control system with high reliability, low failure rate and low cost.
Patent Information
- Application Number
- CN202511041028.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-28
- Publication Date
- 2025-10-28
AI Technical Summary
The existing electric pitch control system has a modular design that results in many connection points, making it prone to oxidation and loosening, leading to high signal transmission delays and bit error rates, high system failure rates, and high costs.
The pitch drive adopts an integrated design, combining the pitch controller, pitch drive, and pitch motor into a single module. It uses silicon carbide semiconductor devices to replace traditional devices, optimizes the power module design, reduces connection points, and improves response speed.
It significantly reduces system failure rate, improves response speed and reliability, reduces hardware costs, simplifies maintenance processes, and adapts to harsh environments.
Smart Images
Figure CN120845241A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of pitch control systems, and more specifically to a pitch control system based on an integrated design. Background Technology
[0002] As a core component of the control system for large wind turbines, the pitch system plays a vital role in the safe, stable, and efficient operation of the unit. Simply put, the pitch system adjusts the pitch angle of the blades to change the angle of attack of the airflow on the blades, thereby controlling the aerodynamic power captured by the wind turbine. Pitch systems are generally classified into two types based on their actuators: electric pitch systems and hydraulic pitch systems.
[0003] In recent years, electric pitch control systems have gradually replaced hydraulic pitch control systems and become the mainstream for large-megawatt wind turbines due to their advantages such as fast response, no risk of oil leakage, and simple and reliable control. In existing technology, the block diagram of a traditional electric pitch control system (single blade) is as follows: Figure 2 As shown, it mainly consists of four core modules: pitch controller, pitch driver, pitch motor, and backup power supply. Based on current usage, this structure has two main problems: First, the four independent modules require electrical and signal connections via cables and connectors, increasing the number of physical connection points (e.g., power lines, communication lines, feedback lines). In harsh environments such as wind power vibration, salt spray, and temperature fluctuations, these connections are prone to oxidation, loosening, or poor contact, significantly increasing the system failure rate (e.g., signal interruption, unstable power supply). Second, the pitch system uses multi-level signal link control. The main control system → pitch controller → pitch driver → pitch motor require sequential transmission of commands and feedback, with each level requiring signal conversion (e.g., digital to analog, PWM generation), increasing cumulative delay (affecting pitch response speed), and leading to electromagnetic interference (EMI) superposition during multi-level transmission, resulting in a higher bit error rate (e.g., encoder feedback signal distortion).
[0004] In general, the four core modules in the existing electric pitch control system are designed independently, resulting in a complex pitch control system structure and many connection points between them, which is an important point of failure in wind turbines. In recent years, some manufacturers have combined the pitch drive and pitch controller into one module, reducing the core modules of the pitch control system to three. This reduces system costs and the failure rate. Summary of the Invention
[0005] This invention provides a pitch control system based on an integrated design. It adopts an integrated pitch driver, which integrates the traditionally separate pitch controller, pitch driver, and pitch motor into a single integrated pitch driver module. This reduces the core modules of the electric pitch system from four (pitch controller, pitch driver, pitch motor, and backup power supply) to two (integrated driver and backup power supply). This not only greatly improves the safety performance and maintainability of the pitch system, but also effectively reduces system costs.
[0006] A pitch control system based on an integrated design includes: multiple independent pitch mechanisms;
[0007] Each independent pitch mechanism includes:
[0008] Wheel hub cabinet;
[0009] An integrated pitch drive electrically connected to the hub cabinet;
[0010] Limit switches electrically connected to the hub cabinet;
[0011] An inductive switch and corresponding connecting cable electrically connected to the hub cabinet;
[0012] The aforementioned independent pitch control mechanism comprises three units. Each independent pitch control mechanism has an integrated pitch driver connected to a reduction gearbox, which in turn connects to the blades. This enables independent pitch control for all three blades. Each blade in the electric pitch control system is equipped with an independent actuator. The pitch motor is connected to the reduction gearbox and, through a drive gear, to the internal gear ring of the pitch bearing, driving the blades to rotate and achieving direct control of the pitch angle. The independent pitch control mechanism provides power input control and sufficient braking capacity to the wind turbine generator, thereby preventing damage to the turbine from overload.
[0013] The hub cabinet is equipped with a backup power module. In case of an emergency such as a power grid failure or control power outage, the pitch system is powered by the backup power system and the blades are quickly adjusted to the feathering position within a short time (e.g., 15 seconds).
[0014] The integrated pitch drive combines the functions of the pitch controller, pitch drive, and pitch motor, reducing the number of connection points and improving system reliability, which is a key feature of this invention.
[0015] The integrated pitch drive includes:
[0016] Permanent magnet synchronous motor;
[0017] A brake is installed at the head of the rotating shaft of the permanent magnet synchronous motor.
[0018] An encoder is installed at the tail of the rotating shaft of the permanent magnet synchronous motor;
[0019] And a servo driver mounted on the housing of the permanent magnet synchronous motor.
[0020] This invention utilizes an integrated pitch drive in a wind power pitch control system, such as... Figure 1 As shown, the pitch system includes: hub cabinet, integrated pitch drive, inductive switches, limit switches and other external equipment, as well as the connecting cables between these devices.
[0021] In this invention, the traditionally separate pitch driver, pitch controller, and pitch motor are integrated into a single module, reducing cable connections and potential points of failure. In terms of hardware integration, the shared power bus and optimized PCB layout reduce the number of cable connections between modules (such as power lines and signal lines).
[0022] The servo driver includes:
[0023] SiC MOSFET module;
[0024] The DSP chip connected to the SiC MOSFET module;
[0025] An ARM processor connected to the DSP chip.
[0026] The SiC MOSFET [Metal-Oxide-Semiconductor Field-Effect Transistor] module includes: a rectifier circuit, an inverter circuit, and a switching circuit, as shown in the specific circuit diagram. Figure 6 and Figure 7 As shown, under normal motoring conditions, the three-phase input power is converted into DC by a SiC MOSFET rectifier circuit, and then into three-phase AC with adjustable voltage and frequency by a SiC MOSFET inverter circuit, finally driving the permanent magnet synchronous motor to rotate. When the servo driver is in braking mode, the SiC MOSFET rectifier circuit and inverter circuit switch. The electrical energy generated by the permanent magnet synchronous motor in braking mode is first converted into DC by the SiC MOSFET rectifier circuit, and then into AC at rated voltage and rated frequency by the SiC MOSFET inverter circuit and fed into the internal power grid.
[0027] In this invention, silicon carbide (SiC) semiconductor devices (SiC MOSFETs) are used to replace traditional IGBTs (Insulated-Gate Bipolar Transistors), leveraging their high-frequency, high-temperature resistance, and low-loss characteristics to optimize the power module design (rectifier and inverter circuits) of the pitch servo driver. The high switching frequency and low conduction loss of SiC semiconductor devices reduce energy loss during switching on and off, lowering the heat dissipation requirements of the switching devices, thus further improving system efficiency and reducing temperature rise. Furthermore, the high-frequency characteristics of SiC semiconductor devices allow for a reduction in the size of passive components such as inductors and capacitors, facilitating integrated layout and supporting compact module design.
[0028] The rectifier circuit is connected to a DC / DC power conversion module for charging the backup power supply. This invention also replaces the diodes (used for uncontrolled rectification) at the front end of the traditional pitch driver with silicon carbide semiconductor devices (SiC MOSFETs), enabling the pitch drive circuit to operate in four quadrants. When the pitch motor is in generating mode (energy recovery braking mode), the electrical energy generated by the pitch motor braking is fed into the internal power grid, eliminating the need for the chopper and braking resistor in the traditional structure.
[0029] The biggest highlight of this design is that it achieves efficient recovery and utilization of pitch braking energy (energy saving) through the high performance and controllability of SiC MOSFETs. At the same time, it completely removes the bulky, energy-consuming, and easily damaged braking resistors and choppers in traditional solutions, thus bringing significant system-level advantages in many aspects such as energy saving, cost reduction (initial and operation and maintenance), efficiency improvement, reliability improvement, weight reduction and capacity reduction.
[0030] The encoder is connected to the permanent magnet synchronous motor and is also connected to the DSP chip.
[0031] The ARM processor is connected to a CANOpen interface.
[0032] The ARM processor is connected to an RS485 interface.
[0033] The ARM processor is connected to an Internet interface.
[0034] The ARM processor is connected to an I / O interface.
[0035] Compared with the prior art, the present invention has the following advantages:
[0036] This invention relates to an integrated pitch control system, employing an integrated pitch driver. By integrating the pitch driver, pitch controller, and pitch motor through an integrated design, it eliminates cables and connectors between modules, reducing the risk of connection failures due to vibration / corrosion, thereby lowering the failure rate. The high-frequency characteristics of silicon carbide devices support compact topology design, facilitating the physical integration of functional modules.
[0037] In the integrated pitch driver of this invention, the controller is directly integrated with the driver hardware layer, and the control commands do not need to be transmitted across modules, which can eliminate signal conversion delay and thus improve the response speed. The internal signals are routed through PCB instead of external cables, thereby reducing EMI interference paths and lowering the bit error rate.
[0038] This invention relates to an integrated pitch control system with a highly integrated pitch driver that combines pitch control, pitch drive, motor, motor brake, and motor encoder. Specifically, the pitch drive uses silicon carbide semiconductor devices instead of traditional IGBTs, leveraging their high-frequency, high-temperature resistance, and low-loss characteristics to further reduce the device size.
[0039] The core advantage of the integrated pitch drive in the pitch control system based on the integrated design of this invention lies in the significant improvement of the reliability and efficiency of the pitch system through silicon carbide (SiC) devices and highly integrated design, while reducing the overall cost.
[0040] First, by replacing traditional IGBTs with SiC devices, leveraging their high-frequency, high-temperature resistance, and low-loss characteristics, the energy efficiency of the power module is optimized, reducing energy loss and heat dissipation requirements. This improves the response speed of the pitch drive and allows it to adapt to more demanding wind farm environments. Second, the integrated design combines the driver, controller, and motor into a single module, eliminating traditional discrete cables and connectors. This reduces physical connection points by more than 80%, effectively solving contact failure problems caused by vibration and salt spray, and significantly improving system reliability. Third, the high switching frequency of SiC devices greatly reduces low-order harmonics generated during inverter operation, further reducing pitch motor losses and allowing for a more compact motor design, facilitating integrated operation. Furthermore, the modular design simplifies power management and maintenance processes, reduces hardware costs, and shortens troubleshooting time, significantly improving the maintainability and economy of the wind turbine. Attached Figure Description
[0041] Figure 1 This is a block diagram of the pitch control system based on the integrated design of the present invention;
[0042] Figure 2 A block diagram of a conventional pitch system (single blade) in the existing technology;
[0043] Figure 3 This is a block diagram of the pitch system (single blade) in this invention;
[0044] Figure 4 This is a schematic diagram of the integrated pitch drive structure in this invention;
[0045] Figure 5 This is a three-dimensional schematic diagram of the integrated pitch drive in this invention;
[0046] Figure 6 This is a schematic diagram of the integrated pitch driver circuit architecture in this invention;
[0047] Figure 7 This is a schematic diagram of the main circuit of the integrated pitch driver in this invention. Detailed Implementation
[0048] In this invention, SiC refers to silicon carbide; IGBT refers to insulated-gate bipolar transistor; and MOSFET refers to metal-oxide-semiconductor field-effect transistor.
[0049] like Figure 1 As shown, the electric pitch control system of this invention mainly consists of an integrated pitch driver, a backup power supply, and external devices such as limit switches. It can achieve independent pitch control for all three blades. Each blade of the pitch control system is equipped with an independent actuator. The integrated pitch driver is connected to a gearbox and is connected to the internal gear ring of the pitch bearing through a drive gear, driving the blade to rotate and achieving direct control of the pitch angle.
[0050] The entire pitch control system consists of three hub cabinets, three integrated pitch actuators, and corresponding inductive switches, limit switches, and other accessories. Power transmission, signal communication, and control command transmission are conducted to the three hub cabinets via slip rings. Each hub cabinet is connected to one integrated pitch actuator for power transmission, signal communication, and control command transmission. Each independent pitch mechanism in the entire pitch control system is equipped with an inductive switch (proximity switch) and a limit switch (mechanical travel switch), serving as critical safety and position monitoring elements. Together, they form multiple protective barriers for the blade pitch angle, ensuring that pitch control operations are performed within a safe range and triggering an emergency stop in extreme situations. A backup power module is located inside the hub cabinet. When the pitch control system loses power, the backup power module supplies power, and the pitch control system enters an emergency stop mode, quickly adjusting the three blades to the feather position to ensure turbine safety. The pitch mechanisms of the three blades are independent of each other; a failure in any one blade does not affect the return of the other two blades.
[0051] like Figure 3 As shown, this invention integrates the pitch driver, pitch controller, and pitch motor into a single unit, eliminating inter-module cables and connectors, reducing the risk of connection failures due to vibration / corrosion, and lowering the failure rate. The high-frequency characteristics of silicon carbide devices support compact topology design, facilitating the physical integration of functional modules. In this invention, the controller and driver hardware layers are directly integrated, eliminating the need for cross-module transmission of control commands, eliminating signal conversion delays, and improving response speed. Internal signals are routed via PCB traces instead of external cables, reducing EMI interference paths and lowering the bit error rate. In this invention, we integrate the pitch controller, pitch driver, and pitch motor into a single module, significantly reducing inter-module wiring, lowering potential failure points, and improving the overall reliability of the pitch system.
[0052] like Figure 4 , Figure 5 As shown, the integrated pitch driver includes: a permanent magnet synchronous motor 2; a brake 1 disposed at the head of the rotating shaft of the permanent magnet synchronous motor 2; an encoder 3 disposed at the tail of the rotating shaft of the permanent magnet synchronous motor 2; and a servo driver 4 mounted on the housing of the permanent magnet synchronous motor 2. The integrated pitch driver of this invention adopts a highly integrated solution, integrating pitch control, pitch drive, motor, motor brake, and motor encoder together. Specifically, the pitch drive uses silicon carbide semiconductor devices instead of traditional IGBTs, utilizing their high-frequency, high-temperature resistance, and low-loss characteristics to further reduce the size of the equipment.
[0053] The circuit structure of the integrated pitch driver of the present invention is as follows: Figure 6As shown, the servo driver 4 includes: a SiC MOSFET and its driving circuit (rectifier / inverter), a SiC MOSFET and its driving circuit (inverter / rectifier), a DSP chip, and an ARM processor connected to the DSP chip. The ARM processor is equipped with a CAN Open interface, an RS485 interface, an INTERNET interface, and I / O interfaces. The permanent magnet synchronous motor 2 is connected to the encoder 3. The encoder signal is decoded and sent to the DSP chip. The voltage and current signals of the permanent magnet synchronous motor 2 are also acquired and sent to the DSP chip. When the pitch motor is in motoring mode, the input three-phase AC power is rectified into DC power by the SiC MOSFET module (i.e., SiC MOSFET and its drive circuit (rectifier / inverter)). The DC power is then inverted into three-phase AC power with adjustable voltage and frequency by the SiC MOSFET module (i.e., SiC MOSFET and its drive circuit (inverter / rectifier)) to drive the pitch motor. When the pitch motor is in generating mode (energy recovery braking mode), the electrical energy generated by the pitch motor braking is rectified into DC power by the SiC MOSFET module. The DC power is then inverted by the SiC MOSFET module and fed into the internal power grid, eliminating the chopper and braking resistor in the traditional structure. Throughout the process, the DSP is responsible for controlling the SiC MOSFET module (including rectification, inversion and switching), the ARM is responsible for processing the pitch control logic and sending the results to the DSP, and is also responsible for handling various external interfaces, including CANOpen, RS485, INTERNET, I / O interfaces, etc.
[0054] To simplify the system structure, reduce costs, and improve integration, this invention integrates the originally separate "charger" function into the "integrated pitch drive," as follows: Figure 7 As shown, the three-phase power supply is connected to the MOSFET driver circuit, which in turn is connected to a DC / DC charger. The MOSFET driver circuit includes current protection, voltage protection, over-temperature protection, and short-circuit protection circuits. An overcurrent protection circuit is also connected between the MOSFET driver circuit and the motor. The specific improvements are as follows:
[0055] 1. Location Selection: Functional integration is selected at the DC Link of the driver. The DC Link is a critical node inside the driver that connects the rectifier unit (which converts AC to DC) and the inverter unit (which converts DC to AC to drive the motor), and contains supporting capacitors to stabilize the DC bus voltage.
[0056] 2. Key Module: A DC / DC power conversion module has been added to the DC link. This module is the core of the integrated charging function.
[0057] 3. Core Function: The main task of this newly added DC / DC module is to charge the backup power module (such as a supercapacitor module). It obtains power from the DC bus (DC Link) of the driver, and then the DC / DC module converts the DC bus voltage and charges the backup power module with appropriate current and voltage.
[0058] 4. Safety Assurance: This integrated charging circuit is not a simple connection, but has comprehensive protection functions, especially:
[0059] Overvoltage protection: Prevents backup power modules (such as supercapacitors) from exceeding their safe voltage limit during charging, thus avoiding damage.
[0060] Current limiting protection: Precisely controls the charging current to ensure it does not exceed the safety limits of the backup power module and the DC / DC module itself, preventing overcurrent damage to components or safety accidents. In addition, it includes other necessary protections (such as over-temperature protection and short-circuit protection).
Claims
1. A pitch control system based on integrated design, comprising: Multiple independent pitch mechanisms, characterized in that each independent pitch mechanism includes: Wheel hub cabinet; An integrated pitch drive electrically connected to the hub cabinet; Limit switches electrically connected to the hub cabinet; An inductive switch electrically connected to the hub cabinet; The integrated pitch drive includes: Permanent magnet synchronous motor; A brake is installed at the head of the rotating shaft of the permanent magnet synchronous motor. An encoder is installed at the tail of the rotating shaft of the permanent magnet synchronous motor; And a servo driver mounted on the housing of the permanent magnet synchronous motor.
2. The pitch control system based on integrated design according to claim 1, characterized in that, There are three independent pitch control mechanisms.
3. The pitch control system based on integrated design according to claim 1, characterized in that, The hub cabinet is equipped with a backup power module.
4. The pitch control system based on integrated design according to claim 1, characterized in that, The servo driver includes: SiC MOSFET module; The DSP chip connected to the SiC MOSFET module; An ARM processor connected to the DSP chip.
5. The pitch control system based on integrated design according to claim 4, characterized in that, The SiCMOSFET module includes a rectifier circuit, an inverter circuit, and a switching circuit.
6. The pitch control system based on integrated design according to claim 4, characterized in that, A DC / DC power conversion module is connected to the rectifier circuit.
7. The pitch control system based on integrated design according to claim 4, characterized in that, The encoder is connected to the permanent magnet synchronous motor and is also connected to the DSP chip via communication.
8. The pitch control system based on integrated design according to claim 4, characterized in that, The ARM processor is connected to a CANOpen interface; The ARM processor is connected to an RS485 interface.
9. The pitch control system based on integrated design according to claim 4, characterized in that, The ARM processor is connected to an Internet interface.
10. The pitch control system based on integrated design according to claim 4, characterized in that, The ARM processor is connected to an I / O interface.