Integrated driver special for wind power variable pitch based on silicon carbide

Abstract

The invention discloses an integrated driver special for wind power variable pitch based on silicon carbide. The integrated driver comprises a permanent magnet synchronous motor; the brake is arranged at the head of a rotating shaft of the permanent magnet synchronous motor; the encoder is arranged at the tail part of a rotating shaft of the permanent magnet synchronous motor; and the servo driver is arranged on a shell of the permanent magnet synchronous motor. The variable-pitch driver, the variable-pitch controller and the variable-pitch motor are integrated through integrated design, cables and connectors between modules can be eliminated, the connection failure risk caused by vibration / corrosion can be reduced, and therefore the failure rate is reduced. The size, the weight and the number of devices of the variable pitch system can be greatly reduced. Meanwhile, system wiring is simplified, and potential fault points are reduced.

Description

Technical Field

[0001] The present invention relates to the field of wind turbine pitch control, and in particular to a dedicated integrated driver for wind turbine pitch control based on silicon carbide. Background Art

[0002] The pitch system is one of the key core subsystems of modern large-scale wind turbines. Its main function is to control the power output and operational safety of the unit by precisely adjusting the pitch angle of the rotor blades (that is, the angle at which the blades rotate around their own longitudinal axis). When the wind speed is lower than the rated wind speed, the system optimizes the pitch angle to capture the maximum wind energy; when the wind speed exceeds the rated wind speed, the blade pitch angle is adjusted to reduce the aerodynamic lift of the blades, so that the wind turbine maintains the rated power output; when the wind speed exceeds the cut-out wind speed or the grid / unit fails, the blades need to be quickly rotated to the feathering position (pitch angle of approximately 90 degrees) to significantly reduce the aerodynamic lift of the blades, prevent the unit from speeding or overloading, and ensure equipment safety. Early pitch systems were mostly hydraulically driven, while modern mainstream units generally use more precise, reliable, and easy-to-maintain electric pitch systems.

[0003] The core modules of the electric pitch system are the pitch motor, pitch driver, backup power supply, and pitch controller. In the traditional structure, these four core modules are designed independently of each other, resulting in a complex pitch system structure with many connection points, which is an important failure point in the wind turbine. In recent years, many manufacturers have combined the pitch driver and pitch controller into one module, reducing the number of core modules of the pitch system to three, which reduces the system cost on the one hand and the system failure rate on the other. The present invention applies silicon carbide semiconductor devices to the field of wind power pitch control, designs a new type of integrated pitch driver, integrates the discrete pitch driver, pitch motor, and pitch controller in the traditional structure, and reduces the number of core modules of the electric pitch system from four to two. This can not only greatly improve the safety performance and maintainability of the pitch system, but also effectively reduce the system cost.

[0004] The traditional pitch system uses four independent modules (pitch drive, pitch controller, pitch motor, and backup power supply). Electrical and signal connections must be achieved between modules through cables and connectors, which will increase the number of physical connection points (such as power lines, communication lines, feedback lines, etc.). In harsh environments such as wind power vibration, salt spray, and temperature changes, the connections are prone to oxidation, loosening, or poor contact, which will lead to a significant increase in the system failure rate (such as signal interruption and unstable power supply). Summary of the Invention

[0005] The present invention provides a dedicated integrated driver for wind turbine pitch control based on silicon carbide. Using this driver significantly reduces the size, weight, and component count of the pitch control system. It also simplifies system wiring and reduces potential points of failure.

[0006] A dedicated integrated driver for wind turbine pitch control based on silicon carbide, comprising:

[0007] Permanent magnet synchronous motor;

[0008] A brake provided at the head of the rotating shaft of the permanent magnet synchronous motor;

[0009] An encoder is provided at the tail end of the rotating shaft of the permanent magnet synchronous motor;

[0010] and a servo driver mounted on the housing of the permanent magnet synchronous motor.

[0011] The silicon carbide-based integrated driver for wind turbine pitch control is developed for the special application environment of wind turbine pitch control systems. It integrates modules such as a programmable controller, a 24-volt switching power supply, a backup power charger, digital input and output, a CANopen interface, and an RS485 interface, and has functions such as backup power supply monitoring and emergency pitching.

[0012] This invention integrates the traditionally separate pitch drive, pitch controller, and pitch motor into a single module, reducing cable connections and potential failure points. Hardware integration reduces inter-module cable connections (such as power and signal lines) by sharing a power bus and optimizing PCB layout.

[0013] The servo driver comprises:

[0014] SiC MOSFET modules;

[0015] A DSP chip connected to the SIC MOSFET module;

[0016] An ARM processor connected to the DSP chip.

[0017] The SIC MOSFET [Metal-Oxide-Semiconductor Field-Effect Transistor] module includes: a rectifier circuit, an inverter circuit and a switching circuit. The specific circuit is as follows Figure 5 and Figure 6As shown in the figure, under normal operation, the three-phase input power is converted into DC by the SIC MOSFET rectifier circuit, and then converted into three-phase AC with adjustable voltage and frequency by the SIC MOSFET inverter circuit, which ultimately drives the permanent magnet synchronous rotation. When the servo drive is in the braking state, the SIC MOSFET rectifier circuit and the inverter circuit are switched. The electrical energy generated by the permanent magnet synchronous motor in the braking state is first converted into DC by the SIC MOSFET rectifier circuit, and then converted into rated voltage and rated frequency AC by the SIC MOSFET inverter circuit and fed into the internal power grid.

[0018] In this invention, silicon carbide semiconductor devices (SiC MOSFETs) are used to replace traditional IGBTs (Insulated-Gate Bipolar Transistors), and their high frequency, high temperature resistance, and low loss characteristics are utilized to optimize the design of the power module (rectifier circuit and inverter circuit) of the servo drive. The high switching frequency and low conduction loss characteristics of silicon carbide semiconductor devices can reduce the energy loss when the switching device is turned on and off, reducing the heat dissipation requirements of the switching device, so that this design can further improve system efficiency and reduce temperature rise. In addition, the high frequency characteristics of silicon carbide semiconductor devices allow the size of passive components such as inductors and capacitors to be reduced, facilitating integrated layout and supporting compact module design.

[0019] The rectifier circuit is connected to a DC / DC power conversion module. The present invention also replaces the diode at the front end of the traditional pitch drive (for uncontrolled rectification) with a silicon carbide semiconductor device (SiC MOSFET), enabling four-quadrant operation of the pitch drive circuit. When the pitch motor is in the generating state (energy recovery braking state), the electrical energy generated by the pitch motor braking is fed into the internal power grid, eliminating the chopper and braking resistor in the traditional structure.

[0020] The biggest highlight of this design is that through the high performance and controllability of SiC MOSFET, it achieves efficient recovery and utilization of variable pitch braking energy (energy saving), while completely removing the bulky, energy-consuming and fragile braking resistors and choppers in traditional solutions, thereby bringing significant system-level advantages in energy saving, cost reduction (initial and operation and maintenance), efficiency improvement, reliability improvement, weight reduction and size reduction.

[0021] The encoder is connected to the permanent magnet synchronous motor, and the encoder is communicatively connected to the DSP chip.

[0022] The ARM processor is connected with a CANOpen interface.

[0023] The ARM processor is connected with an RS485 interface.

[0024] The ARM processor is connected with an INTERNET interface.

[0025] The ARM processor is connected with an I / O interface.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] This invention integrates the pitch drive, pitch controller, and pitch motor through an integrated design, eliminating inter-module cables and connectors, reducing the risk of connection failures caused by vibration and corrosion, and thus lowering the failure rate. The high-frequency characteristics of silicon carbide devices support a compact topology design, facilitating the physical integration of functional modules.

[0028] In the present invention, the controller is directly integrated with the driver hardware layer, and the control instructions do not need to be transmitted across modules, which can eliminate signal conversion delays, thereby improving the response speed. Internal signals are routed through PCB instead of external cables, thereby reducing EMI interference paths and reducing the bit error rate.

[0029] The integrated drive of this invention utilizes a highly integrated solution, integrating the pitch control, pitch drive, motor, motor brake, and motor encoder. The pitch drive uses silicon carbide semiconductor devices instead of traditional IGBTs, leveraging their high frequency, high temperature resistance, and low loss to further reduce the device size.

[0030] The core advantage of the present invention is that the reliability and efficiency of the variable pitch system are significantly improved while reducing the overall cost through silicon carbide (SiC) devices and highly integrated design.

[0031] First, SiC devices replace traditional IGBTs, leveraging their high frequency, high temperature resistance, and low loss characteristics to optimize the energy efficiency of the power module, reduce energy loss and heat dissipation requirements, increase the response speed of the pitch drive, and adapt to more stringent wind farm environments. Second, through an integrated design, the driver, controller, and motor are integrated into a single module, eliminating traditional discrete cables and connectors, reducing physical connection points by over 80%, effectively solving contact failures caused by vibration and salt spray, and significantly improving system reliability. Third, the high switching frequency of SiC devices can greatly reduce the low-order harmonics generated during the inverter process, further reducing the losses of the pitch motor, making the motor design more compact and facilitating integrated integration. In addition, the modular design simplifies power management and maintenance processes, reduces hardware costs, and shortens troubleshooting time, significantly improving the maintainability and cost-effectiveness of wind turbines. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a block diagram of a conventional variable pitch system (single blade) in the prior art;

[0033] Figure 2 This is a block diagram of a pitch system (single blade) using the integrated drive of the present invention;

[0034] Figure 3 This is a schematic diagram of the integrated driver structure of the present invention;

[0035] Figure 4 A three-dimensional schematic diagram of the integrated driver of the present invention;

[0036] Figure 5 This is a schematic diagram of the integrated driver circuit architecture of the present invention;

[0037] Figure 6 This is a schematic diagram of the main circuit of the integrated driver of the present invention;

[0038] Figure 7 This is a schematic diagram of the pitch control state logic of the present invention. DETAILED DESCRIPTION

[0039] like Figure 1 As shown in the figure, a traditional electric pitch system includes a pitch controller (pitch PLC), a pitch driver (pitch inverter), a pitch motor, a backup power supply (such as a supercapacitor), and external devices (such as limit switches and proximity switches). Each blade in an electric pitch system is equipped with an independent actuator. The pitch motor is connected to a reduction gearbox and, via a driving gear, to the inner ring gear of the blade gear, driving the blades to rotate and directly controlling the pitch angle. When the wind turbine is in normal power generation, the pitch system follows the instructions of the wind turbine master PLC and drives the pitch motor to adjust the blades to the specified pitch angle. In the event of a fault, such as loss of communication with the wind turbine master PLC, the pitch system automatically drives the pitch motor to adjust the blades to the feathered position and restarts again after the fault is resolved. If the pitch system detects a grid fault, it enters an emergency feathering state. Powered by the backup power supply, the pitch system rapidly adjusts the blades to the feathered position within a short period of time (e.g., 15 seconds).

[0040] like Figure 2 As shown, the wind turbine pitch-shifting dedicated integrated driver of the present invention will Figure 1 The pitch controller, pitch drive and pitch motor are integrated into one module, which greatly reduces the connection between modules and reduces the failure points, making the pitch system design simpler and improving the reliability of the entire pitch system.

[0041] In traditional pitch control systems, the pitch drive and pitch motor are two independent components. The former is installed in the pitch control cabinet and provides the pitch motor with adjustable power output according to the pitch controller's instructions. The latter is installed in the wheel hub and drives the blades through the pitch gearbox and pitch bearings. This split-type hardware layout of the pitch drive and pitch motor results in numerous cables connecting them, including drive cables, brake cables, and encoder cables for each blade. Consequently, this layout in traditional pitch control systems results in significant cable material costs and labor costs, as well as a high probability of error and error correction during wiring and routing. Furthermore, the pitch motor cables in the system act like countless high-power radio frequency antennas, becoming a source of electromagnetic noise interference and a potential risk, impacting the system's EMC performance, equipment stability, and operational efficiency. Therefore, the use of the present invention's dedicated integrated wind turbine pitch drive significantly reduces the size, weight, and component count of the pitch control system. It also simplifies system wiring and reduces potential points of failure.

[0042] like Figure 3 、 Figure 4 As shown, the integrated drive comprises a permanent magnet synchronous motor 2; a brake 1 mounted at the head of the motor's rotating shaft; an encoder 3 mounted at the tail of the motor's rotating shaft; and a servo drive 4 mounted on the housing of the motor. This integrated drive utilizes a highly integrated solution, integrating the pitch control, pitch drive, motor, motor brake, and motor encoder. The pitch drive utilizes 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.

[0043] The circuit structure of the integrated driver of the present invention is as follows Figure 5As shown, the servo driver 4 includes: SiC MOSFETs and their drive circuits (rectifier / inverter), SiC MOSFETs and their drive circuits (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 an I / O interface. 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 collected and sent to the DSP chip. When the pitch motor is in the electric state, the input three-phase AC power is rectified into DC power by the SIC MOSFET module (i.e., SiC MOSFET and its drive circuit (rectification / inversion)), and 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 (inversion / rectification)) to drive the pitch motor; when the pitch motor is in the power generation state (energy recovery braking state), the electric energy generated by the pitch motor braking is rectified into DC power by the SIC MOSFET module, and the DC power is then fed into the internal power grid through the SIC MOSFET module, eliminating the chopper and braking resistor in the traditional structure; throughout the entire 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 processing various external interfaces, including CANOpen, RS485, INTERNET, I / O interfaces, etc.

[0044] In order to simplify the system structure, reduce costs and improve integration, the present invention integrates the original independent "charger" function into the "integrated driver" as follows Figure 6 As shown, the three-phase power supply is connected to the MOSFET drive circuit, which is then connected to a DC / DC charger. The MOSFET drive circuit is connected to a current protection circuit, a voltage protection circuit, an overtemperature protection circuit, and a short-circuit protection circuit. An overcurrent protection circuit is also connected between the MOSFET drive circuit and the motor. Specific improvements are as follows:

[0045] 1. Location: The DC link of the drive is selected for functional integration. The DC link is a key node within the drive that connects the rectifier unit (which converts AC power to DC) and the inverter unit (which converts DC power to AC power to drive the motor). It contains support capacitors to stabilize the DC bus voltage.

[0046] 2. Key Module: A DC / DC power conversion module is added to the DC link. This module is the core of the integrated charging function.

[0047] 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 link of the drive. The DC / DC module then converts the DC link voltage and charges the backup power module with the appropriate current and voltage.

[0048] 4. Safety Assurance: The integrated charging circuit is not just a simple connection, but has comprehensive protection functions, especially:

[0049] Overvoltage protection: Prevents the voltage of the backup power module (such as supercapacitor) from exceeding its safety upper limit during charging to avoid damage.

[0050] Current limiting protection: This precisely controls the charging current, ensuring it does not exceed the safety limits of the backup power module and the DC / DC module itself, preventing overcurrent damage to components or accidents. Other necessary protections, such as overtemperature protection and short-circuit protection, are also included.

[0051] like Figure 7 As shown in FIG. 1 , the pitch control logic of the integrated drive of the present invention is as follows: Figure 7 As shown, the main states are wind farm application state, wind farm application stop state, wind farm application operation state, and wind farm application emergency feathering state. The wind farm application stop state receives commands from the main control to maintain the blades in a fixed position; the wind farm application operation state receives commands from the main control to move the blades to a specific position; and the wind farm application emergency feathering state directly drives the blades back to the feathered position in an emergency. Emergency states include loss of communication with the main control, disconnection of the turbine safety chain, disconnection of the pitch safety chain, and pressing of the emergency stop button. These states transition between each other under certain conditions. Control logic integration embeds the pitch control algorithm into the driver hardware, eliminating multi-stage signal transmission delays and improving response speed. The motor's built-in encoder also communicates with the driver in real time, enabling precise control of the pitch angle.

Claims

1. A dedicated integrated driver for wind turbine pitch control based on silicon carbide, characterized in that: include: Permanent magnet synchronous motor; A brake provided at the head of the rotating shaft of the permanent magnet synchronous motor; An encoder is provided at the tail end of the rotating shaft of the permanent magnet synchronous motor; and a servo driver mounted on the housing of the permanent magnet synchronous motor; The servo driver comprises: SiC MOSFET modules; A DSP chip connected to the SIC MOSFET module; An ARM processor connected to the DSP chip.

2. The silicon carbide-based wind turbine pitch-variable dedicated integrated driver according to claim 1, characterized in that: The SIC MOSFET module includes: a rectifier circuit, an inverter circuit and a switching circuit.

3. The silicon carbide-based wind turbine pitch-variable dedicated integrated driver according to claim 1, characterized in that: The rectifier circuit is connected to a DC / DC power conversion module.

4. The silicon carbide-based wind turbine pitch-variable dedicated integrated driver according to claim 1, characterized in that: The encoder is connected to the permanent magnet synchronous motor, and the encoder is communicatively connected to the DSP chip.

5. The silicon carbide-based wind turbine pitch-variable dedicated integrated driver according to claim 1, characterized in that: The ARM processor is connected with a CANOpen interface.

6. The silicon carbide-based wind turbine pitch-variable dedicated integrated driver according to claim 1, characterized in that: The ARM processor is connected with an RS485 interface.

7. The silicon carbide-based wind turbine pitch-variable dedicated integrated driver according to claim 1, characterized in that: The ARM processor is connected with an INTERNET interface.

8. The silicon carbide-based wind turbine pitch-variable dedicated integrated driver according to claim 1, characterized in that: The ARM processor is connected with an I / O interface.

9. The silicon carbide-based wind turbine pitch-variable dedicated integrated driver according to claim 1, characterized in that: The integrated driver is only used in the field of wind turbine pitch control.

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