Off-grid system control method and device for small wind driven generator without wind speed sensor
By establishing a mechanical energy model and aerodynamic simulation of wind turbine blades, and combining measured data to optimize the output power and voltage curves of wind turbines, the problems of low wind energy capture efficiency and voltage matching under conditions without wind speed sensors were solved, thus achieving efficient wind power generation.
Patent Information
- Application Number
- CN202511884813.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-27
- Publication Date
- 2026-02-24
AI Technical Summary
Existing small off-grid wind turbine systems have low wind energy capture efficiency and poor matching between wind energy and generator output voltage under the condition of no wind speed sensor, resulting in poor power generation efficiency. Furthermore, the controller is prone to overcurrent at high wind speeds, which triggers the unloading circuit, and the effective power generation wind speed range is not high.
A mechanical energy model of wind turbine blades is established. The optimal rotational speed curves under different wind speeds are fitted through aerodynamic simulation. Combined with measured data, the output power and voltage curves of the generator are determined to achieve end-to-end parameter matching and optimize the operation mode.
This improved the accuracy of the speed-power curves of wind turbines at different wind speeds, enhanced system precision and power generation efficiency, and enabled efficient wind energy capture and stable output under conditions without wind speed sensors.
Smart Images
Figure CN121557039A_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of generator off-grid system control technology, and specifically relates to a control method, device, equipment and medium for a small wind turbine off-grid system without wind speed sensor. Background Technology
[0002] At a critical juncture in the global energy structure's transition towards cleaner and lower-carbon energy sources, the development and utilization of renewable energy has become a core strategic direction for addressing climate change and alleviating the pressure of traditional fossil fuel depletion. Wind energy, as a clean energy source with abundant reserves, wide distribution, and recyclability, directly impacts the progress of energy transition, and wind turbines, as the core equipment for wind energy conversion, have received significant attention from the global energy sector. With the large-scale development of the wind power industry, the market has placed increasingly stringent demands on the power generation efficiency, stability, and economic viability of wind turbines. How to further improve wind energy capture efficiency and optimize the energy conversion chain has become a core challenge for technological innovation in the industry.
[0003] Currently, the control methods for off-grid systems of small wind turbines typically involve connecting the three-phase AC power generated by the turbine to a controller, where it is rectified into DC voltage by an internal three-phase uncontrolled rectifier bridge. This DC voltage is then directly connected to the battery, or connected via a DC / DC converter circuit, charging the battery according to a set voltage-current curve. In the mode where the rectified voltage is directly connected to the battery, the system's rotational speed is heavily influenced by the battery, resulting in low wind energy capture efficiency at different wind speeds and poor overall power generation efficiency. In the mode where the rectified voltage is connected to the battery via a DC / DC converter circuit, charging the battery according to a set voltage-current curve, the following issues arise. If the current curve corresponding to the voltage is too small, the turbine speed may be too high, leading to low wind energy capture efficiency; if the current curve is too large, the turbine speed may be limited, also resulting in low wind energy capture efficiency. Furthermore, when using a DC / DC converter circuit to connect to the battery, at high wind speeds, the controller reaches an overcurrent value, triggering a load shedding circuit, thus limiting the effective power generation wind speed range. Summary of the Invention
[0004] In view of the above problems, this application proposes a control method, device, equipment, and medium for an off-grid system of a sensorless small wind turbine. This solves the problems of low wind energy capture efficiency and mismatch between wind energy and generator output voltage in sensorless small wind turbines.
[0005] This application provides a control method for an off-grid system of a small wind turbine without a wind speed sensor, including:
[0006] A mechanical energy model is established based on the wind turbine system and wind turbine blades. Based on the mechanical energy model, the first curve of the generator speed and mechanical energy of the turbine blades under different wind speeds is obtained.
[0007] The mechanical energy captured by the wind turbine blades is obtained from the first curve, and the output power of the wind turbine is determined based on the mechanical energy.
[0008] A second curve of generator speed versus output voltage is determined based on the output power of the wind turbine;
[0009] The first curve of generator speed versus mechanical energy and the second curve of generator speed versus output voltage under different wind speeds are fitted to obtain the third curve of wind turbine output voltage versus output power.
[0010] The operating mode of the wind turbine system under different operating conditions is matched based on the third curve.
[0011] Furthermore, the establishment of a mechanical energy model based on the wind turbine system and wind turbine blades includes:
[0012] A wind power generation system model is established based on the parameters of wind turbine airfoil, wind turbine chord length, wind turbine radius, and wind farm type in the wind turbine system.
[0013] Mechanical energy is captured based on the wind power generation system model, and a mechanical energy model of the wind power generation system is obtained based on the captured mechanical energy.
[0014] Furthermore, obtaining the first curve of generator speed versus generator blade mechanical energy at different wind speeds based on the mechanical energy model includes:
[0015] Set a wind speed curve, and fit the wind turbine generator speed curve to the wind speed curve.
[0016] According to the generator speed curve, the generator speed at different wind speeds corresponds to the first curve of the mechanical energy of the wind turbine blades generating the generator speed and the mechanical energy of the turbine blades in the mechanical energy model.
[0017] Furthermore, the step of obtaining the mechanical energy captured by the wind turbine blades based on the first curve, and determining the output power of the wind turbine based on the mechanical energy, includes:
[0018] The maximum mechanical energy captured by the wind turbine blades at different wind speeds is obtained from the first curve.
[0019] The output power of the wind turbine is determined based on the maximum mechanical energy, the first conversion efficiency between the wind turbine blades and the generator, and the second conversion efficiency output by the generator controller.
[0020] Furthermore, the determination of the second curve of generator speed versus output voltage based on the output power of the wind turbine includes:
[0021] The wind turbine's speed curve is determined based on its output power.
[0022] The curve of the wind turbine's output voltage is determined based on the wind turbine's output power;
[0023] The output voltage curve of the wind turbine is fitted with the corresponding speed curve of the generator to obtain a second curve of generator speed versus output voltage.
[0024] Furthermore, the process of fitting the first curve of generator speed versus mechanical energy and the second curve of generator speed versus output voltage under different wind speeds to obtain the third curve of wind turbine output voltage versus output power includes:
[0025] Based on the rotational speed points in the first curve where the maximum mechanical energy captured by the blades corresponds to the generator speed at different wind speeds, the generator output power is obtained.
[0026] Based on the rotational speed at which the blade captures the maximum mechanical energy, the wind turbine output voltage is obtained from the second curve;
[0027] The third curve of wind turbine output voltage versus output power is obtained based on the output power of the generator and the output voltage of the wind turbine.
[0028] Furthermore, the matching of operating modes of the wind turbine system under different operating conditions based on the third curve includes:
[0029] The operating conditions are set based on the voltage output after rectification of the generator output voltage in the third curve.
[0030] Among them, when the output voltage after rectification is lower than the minimum operating voltage, the matching condition is the low wind speed operation condition, and the output power is zero.
[0031] When the rectified output voltage is greater than the minimum operating voltage, the matching condition is medium to high wind speed operation. At this time, the output power is output according to the output power corresponding to the generator output voltage in the third curve.
[0032] When the rectified output current is higher than the maximum operating current, the matching condition is the ultra-high wind speed operation condition, and the unloading mode is activated.
[0033] Based on the same inventive concept, another aspect of this application provides a sensorless off-grid system control device for a small wind turbine, comprising:
[0034] The model building unit is used to build a mechanical energy model based on the wind turbine system and wind turbine blades, and to obtain the first curve of the generator speed and mechanical energy of the turbine blades under different wind speeds based on the mechanical energy model.
[0035] A power determination unit is used to obtain the mechanical energy captured by the wind turbine blades based on the first curve, and to determine the output power of the wind turbine based on the mechanical energy.
[0036] A curve determination unit is used to determine a second curve of generator speed and output voltage based on the output power of the wind turbine generator;
[0037] The curve fitting unit is used to fit the first curve of generator speed versus mechanical energy and the second curve of generator speed versus output voltage under different wind speeds to obtain the third curve of wind turbine output voltage versus output power.
[0038] The matching unit is used to match the operating modes of the wind turbine system under different operating conditions based on the third curve.
[0039] Based on the same inventive concept, another aspect of the embodiments of this application provides an electronic device, including: a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus;
[0040] Memory, which stores computer programs;
[0041] When the processor executes the program stored in the memory, it implements a control method for an off-grid system of a small wind turbine without a wind speed sensor.
[0042] Based on the same inventive concept, another aspect of the embodiments of this application provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements a control method for an off-grid system of a small wind turbine without a wind speed sensor.
[0043] The beneficial effects of this application are:
[0044] This application establishes a physical model of wind turbine blades by combining parameters such as airfoil, chord length, blade length, and rotor radius. It also establishes an accurate model for capturing mechanical energy from the wind turbine blades by considering the wind farm type of the wind turbine system, the physical model of the turbine, and the installation angle of the wind farm. Using aerodynamic simulation, it can accurately fit the optimal speed curve corresponding to the maximum captured mechanical energy of different wind turbine models at various wind speeds, improving the accuracy of the speed-power curves when the system operates with different types of wind turbines.
[0045] By using a motor speed-voltage testing platform, the simulation data and the actual measured data of the motor hardware are verified and integrated in two directions, which improves the accuracy of the data and the precision of the entire system.
[0046] In scenarios without wind speed sensors, the optimal rotational speed curve obtained from blade aerodynamic simulation is used as a basis, and the voltage-current curve obtained from actual measurement and simulation is combined to directly provide the controller with the basis for voltage-current dual-parameter control, thereby achieving end-to-end parameter matching from blade mechanical energy capture to motor output.
[0047] Other features and advantages of this application will be set forth in the following description and will be apparent in part from the description or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures pointed out in the description and the accompanying drawings. Attached Figure Description
[0048] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0049] Figure 1 A flowchart of a control method for an off-grid system of a small wind turbine without a wind speed sensor is shown in an embodiment of this application.
[0050] Figure 2 A schematic diagram of the physical model of the wind turbine generator in an embodiment of this application is shown;
[0051] Figure 3 A schematic diagram of the wind turbine speed-voltage measurement platform in an embodiment of this application is shown;
[0052] Figure 4 A schematic diagram of the off-grid system structure of a small wind turbine generator is shown in an embodiment of this application;
[0053] Figure 5 The following is a flowchart illustrating the operating modes of the wind turbine generator system under various working conditions in the embodiments of this application;
[0054] Figure 6 A schematic diagram of the first curve in an embodiment of this application is shown;
[0055] Figure 7 A schematic diagram of the second curve in an embodiment of this application is shown;
[0056] Figure 8 A schematic diagram of the third curve in an embodiment of this application is shown;
[0057] Figure 9 A schematic diagram of a sensorless off-grid system control device for a small wind turbine generator is shown in an embodiment of this application.
[0058] Figure 10 A schematic diagram of an electronic device according to an embodiment of this application is shown. Detailed Implementation
[0059] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0060] It should be noted that the terms "first," "second," etc., used in this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," "longitudinal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings.
[0061] This application provides a sensorless control method for an off-grid system of a small wind turbine. (See also...) Figure 1 ,include:
[0062] S101: Establish a mechanical energy model based on the wind turbine system and wind turbine blades, and obtain the first curve of the generator speed and mechanical energy of the turbine blades under different wind speeds based on the mechanical energy model.
[0063] S102: Obtain the mechanical energy captured by the wind turbine blades based on the first curve, and determine the output power of the wind turbine based on the mechanical energy;
[0064] S103: Determine the second curve of generator speed versus output voltage based on the output power of the wind turbine;
[0065] S104: The third curve of wind turbine output voltage and output power is obtained by fitting the first curve of generator speed versus mechanical energy and the second curve of generator speed versus output voltage under different wind speeds;
[0066] S105: Based on the third curve, the operating mode of the wind turbine system is matched under different operating conditions.
[0067] The sensorless small wind turbine off-grid system control method described in the embodiments of this specification is typically used in servers, which can be cloud servers or local servers. Servers can be electronic devices such as laptops, desktop computers, tablets, and all-in-one computers.
[0068] Specifically, in step S101, establishing a mechanical energy model based on the wind turbine system and wind turbine blades includes:
[0069] A wind power generation system model is established based on the parameters of wind turbine airfoil, wind turbine chord length, wind turbine radius, and wind farm type in the wind turbine system.
[0070] Mechanical energy is captured based on the wind power generation system model, and a mechanical energy model of the wind power generation system is obtained based on the captured mechanical energy.
[0071] Specifically, in the embodiments of this application, the mechanical energy capture model of the wind turbine system blades is described in [reference needed]. Figure 2 , Figure 2 This is a model diagram of a wind turbine system blade capturing mechanical energy. 201 is the front view of the model, and 202 is the top view of the model. The model includes the following parameters: 203 blade airfoil, 204 blade chord length, 205 blade length, and 206 rotor radius.
[0072] The wind turbine system blade mechanical energy capture model includes establishing a physical model of the wind turbine blade based on the wind turbine airfoil, chord length, blade length, and rotor radius parameters in the wind turbine system; the wind farm type of the wind turbine system; and the wind turbine physical model and wind farm installation angle.
[0073] Specifically, obtaining the first curve of generator speed versus generator blade mechanical energy at different wind speeds based on the mechanical energy model includes:
[0074] Set a wind speed curve, and fit the wind turbine generator speed curve to the wind speed curve.
[0075] According to the generator speed curve, the generator speed at different wind speeds corresponds to the first curve of the mechanical energy of the wind turbine blades generating the generator speed and the mechanical energy of the turbine blades in the mechanical energy model.
[0076] Specifically, a wind turbine blade mechanical energy capture model is established by combining the wind turbine physical model, the wind farm type of the wind turbine system, and the wind turbine physical model with the wind farm installation angle. In step S101, based on the wind turbine blade mechanical energy capture model, simulations are performed on the mechanical energy captured by the blades at different wind speeds and rotational speeds. See [link to relevant documentation]. Figure 6Fit the optimal rotational speed curve RPM corresponding to the maximum mechanical energy captured by the blades of the wind turbine at various wind speeds (PM_mp_n). MP_n ;
[0077] f: PM_mp_n→RPM MP_n
[0078] Where n represents different wind speeds, RPM MP_n The curve represents the optimal rotational speed point, and PM_mp_n represents the maximum mechanical energy captured by the blades.
[0079] Specifically, in step S102, obtaining the mechanical energy captured by the wind turbine blades based on the first curve and determining the output power of the wind turbine based on the mechanical energy includes:
[0080] The maximum mechanical energy captured by the wind turbine blades at different wind speeds is obtained from the first curve.
[0081] The output power of the wind turbine is determined based on the maximum mechanical energy, the first conversion efficiency between the wind turbine blades and the generator, and the second conversion efficiency output by the generator controller.
[0082] Specifically, in step S103, determining the second curve of generator speed versus output voltage based on the output power of the wind turbine includes:
[0083] The wind turbine's speed curve is determined based on its output power.
[0084] The curve of the wind turbine's output voltage is determined based on the wind turbine's output power;
[0085] The output voltage curve of the wind turbine is fitted with the corresponding speed curve of the generator to obtain a second curve of generator speed versus output voltage.
[0086] Specifically, see Figure 3A motor speed-voltage curve testing platform was constructed, comprising the following equipment: a drive motor 301, a magnetic coupling connector 302, a motor under test (DUT) 303, an oscilloscope 304, a rectifier 305, and an adjustable electronic load 306. One side of the magnetic coupling connector 302 is connected to the drive motor 301, and the other side is connected to the DUT 303. The output power of the DUT 303 is adjusted by regulating the magnetic coupling degree of the connector 302. The oscilloscope 304 is connected to the output voltage of the DUT 303, and the motor speed is calculated by measuring the frequency of the output voltage. Simultaneously, the output voltage of the DUT 303 is rectified into DC voltage by the rectifier 305 and connected to the adjustable electronic load 306. The output voltage and speed are changed by adjusting the resistance of the adjustable electronic load 306. The adjustable electronic load 306 can also be used to measure the output voltage and output power of the DUT 303.
[0087] See Figure 7 Based on the maximum mechanical energy captured by the blades at various wind speeds, P M_mp_n Measure the corresponding output power P out_n The corresponding speed (RPM) of the generator MP_n With generator output voltage V out curve;
[0088] f: RPM MP_n →V out
[0089] Among them, the maximum value P of the mechanical energy captured by the blades at each wind speed M_mp_n Different output power P measured out_n The relationship is as follows:
[0090] P out_n =P M_mp_n *η1*η2
[0091] Where η1 is the first conversion efficiency from the wind turbine blades to the generator, and η2 is the output conversion efficiency of the controller.
[0092] Specifically, in step S104, fitting the first curve of generator speed versus mechanical energy and the second curve of generator speed versus output voltage under different wind speeds to obtain the third curve of wind turbine output voltage versus output power includes:
[0093] Based on the rotational speed points in the first curve where the maximum mechanical energy captured by the blades corresponds to the generator speed at different wind speeds, the generator output power is obtained.
[0094] Based on the rotational speed at which the blade captures the maximum mechanical energy, the wind turbine output voltage is obtained from the second curve;
[0095] The third curve of wind turbine output voltage versus output power is obtained based on the output power of the generator and the output voltage of the wind turbine.
[0096] Specifically, based on the optimal rotational speed curve corresponding to the maximum mechanical energy captured by the blades at each wind speed and the rotational speed-voltage curve corresponding to the generator at different power levels, the generator output voltage V is... out Converted to rectified voltage V out_DC The optimal output voltage-output power curve of the wind turbine at various wind speeds is fitted as a reference for the output power of the controller.
[0097] f:V out_DC →P out_n
[0098] Among them, the output voltage V out and the rectified output voltage V out_DC The relationship is as follows:
[0099] V out_DC =1.414*V out
[0100] It should be noted that, in the embodiments of this application, through Figure 3 The motor speed-voltage curve test platform shown uses magnetic coupling connector 302 to change the input power of the motor under test 303, while simultaneously adjusting the regulator of adjustable electronic load 306 to adjust the speed, and simultaneously measuring voltage and power parameters. (See [link to relevant documentation]). Figure 8 Ultimately, this allows for the fitting of the optimal output voltage-output power curve of the wind turbine system under various wind speed conditions.
[0101] Specifically, in step S105, the matching of operating modes of the wind turbine system under different operating conditions based on the third curve includes:
[0102] The operating conditions are set based on the voltage output after rectification of the generator output voltage in the third curve.
[0103] Among them, when the output voltage after rectification is lower than the minimum operating voltage, the matching condition is the low wind speed operation condition, and the output power is zero.
[0104] When the rectified output voltage is greater than the minimum operating voltage, the matching condition is medium to high wind speed operation. At this time, the output power is output according to the output power corresponding to the generator output voltage in the third curve.
[0105] When the rectified output current is higher than the maximum operating current, the matching condition is the ultra-high wind speed operation condition, and the unloading mode is activated.
[0106] Specifically, the starting voltage V of the wind turbine system is set according to the wind speed, the maximum output parameters of the generator, and the maximum input parameters of the controller. start Maximum input current I max Set the maximum speed (RPM) max ;
[0107] Based on the output voltage V after rectification by the fan out_DC The rectified output current I out_DC Optimal output voltage-output power curves at various wind speeds, minimum operating voltage V start Maximum input current I max Maximum speed RPM max Set the various operating conditions and their operation modes of the wind turbine generator system.
[0108] It should be noted that the wind power generation system in the embodiments of this application refers to... Figure 4 The system includes the following components: a wind turbine generator 401, a controller 402, an energy storage battery 403, a load-relief resistor 404, an inverter 405, electrical equipment 406, and a remote monitoring platform 407. The wind turbine generator 401 stores electrical energy in the energy storage battery 403 via the controller 402. The stored electrical energy powers the electrical equipment 406 via the inverter 405. When the wind speed is too high, the controller 402 unloads the wind turbine generator 401 through the load-relief resistor 404. The controller 402 includes a rectifier module 402-1, a DC / DC boost module 402-2, and a load-relief module 402-3.
[0109] The following section provides a detailed explanation of the operation mode matching of the wind turbine system under different operating conditions, using the third curve in the embodiments of this application.
[0110] See Figure 5 and Figure 8 The matching formulas for each operating condition are as follows:
[0111]
[0112] Under low wind speed operating conditions, the voltage V of the fan output after passing through the rectifier module 402-1 is... out_ DC At start, under the aforementioned low wind speed condition, the controller output power P out =0.
[0113] Under medium-to-high wind speed operating conditions, the output voltage of the wind turbine is rectified by the voltage V of the rectifier module 402-1. out_DC >V start When the DC / DC boost module 402-2 is working, the wind turbine output current operates according to the optimal output voltage-output power curve of the wind turbine at various wind speeds.
[0114] f:V out_DC →P out_n
[0115] Under high wind speed operating conditions, when in I out_DC >I max Or RPM > RPM max When the controller 402-3 unloading module is working, it discharges power and limits the speed of the wind turbine through the unloading resistor 404.
[0116] The following examples illustrate the application of embodiments of this application.
[0117] A sensorless, small vertical-axis wind turbine off-grid system is disclosed. The turbine blades adopt NASA-0015 airfoil design with a chord length of 0.4m, a blade length of 2.5m, a turbine radius of 1m, and the wind field uses the average wind speed. The turbine is installed perpendicular to the ground, facing the wind. The generator has a rated speed of 260RPM, a rated power of 1.2kW, and a rated voltage of 36Vac. The energy storage unit uses a 51.2V lithium iron phosphate battery. Figure 6 This presents simulation data of the mechanical energy captured by the blades under different wind speeds and rotational speeds. Figure 7 This is the maximum power curve corresponding to each wind speed.
[0118] The wind speeds n are 3, 5, 8, 10, and 12 m / s, respectively.
[0119] Corresponding to the optimal speed RPM MP_n The values are 64, 106, 170, 212, and 255 RPM, respectively.
[0120] Corresponding maximum mechanical power P M_mp_n The values are 30, 120, 510, 990, and 1710W, respectively.
[0121] Corresponding maximum output power P out_n The numbers are 22, 86, 367, 713, and 1231W, respectively.
[0122] Among them, the energy conversion efficiency η1 from the wind turbine blades to the generator is taken as 80%, and the output conversion efficiency η2 of the controller is taken as 90%.
[0123] Figure 8 For the controller voltage-output power curve, through Figure 3 The test platform for the motor speed-voltage curve shown is used to test the output power P. out_n And corresponding to the optimal RPM MP_n The rectified voltage V out_DC_n Finally, the wind speed n and the rectified voltage V are compared. out_DC_n Output power P out_nBy fitting, a reference curve of controller voltage-output power is obtained, and a reference mathematical relationship of controller voltage-output power is fitted.
[0124] The specific test data are as follows: when the wind speed n = 3 m / s, 5 m / s, 8 m / s, 10 m / s, and 12 m / s,
[0125] Rectified voltage V out_DC_n The corresponding values are 13Vdc, 22Vdc, 34Vdc, 41Vdc, and 48Vdc.
[0126] Corresponding output power P out_n The respective values are 22W, 86W, 367W, 713W, and 1231W.
[0127] After fitting P out and V out_DC Mathematical Relationship
[0128] P out =0.0054V out_DC 3.17
[0129] The wind turbine has a rated speed of 260 RPM and a maximum speed of 300 RPM. The maximum input current after rectification by the controller is 30A. Based on this, the protection parameters are configured as follows: RPMmax = 300 RPM, Imax = 27A. Considering the low power generation at a wind speed of 3 m / s, the starting voltage Vstart is set to the rectified voltage of the controller under the condition of a wind speed of 5 m / s, i.e., Vstart = 25V.
[0130] This application establishes a physical model of wind turbine blades by combining parameters such as airfoil, chord length, blade length, and rotor radius. It also establishes an accurate model for capturing mechanical energy from the wind turbine blades by considering the wind farm type of the wind turbine system, the physical model of the turbine, and the installation angle of the wind farm. Using aerodynamic simulation, it can accurately fit the optimal speed curve corresponding to the maximum captured mechanical energy of different wind turbine models at various wind speeds, improving the accuracy of the speed-power curves when the system operates with different types of wind turbines.
[0131] By using a motor speed-voltage testing platform, the simulation data and the actual measured data of the motor hardware are verified and integrated in two directions, which improves the accuracy of the data and the precision of the entire system.
[0132] In scenarios without wind speed sensors, the optimal rotational speed curve obtained from blade aerodynamic simulation is used as a basis, and the voltage-current curve obtained from actual measurement and simulation is combined to directly provide the controller with the basis for voltage-current dual-parameter control, thereby achieving end-to-end parameter matching from blade mechanical energy capture to motor output.
[0133] Based on the same inventive concept, another aspect of this application provides a sensorless control device for a small off-grid wind turbine system, see [link to relevant documentation]. Figure 9 ,include:
[0134] The model building unit 901 is used to build a mechanical energy model based on the wind turbine system and wind turbine blades, and to obtain the first curve of the generator speed and mechanical energy of the turbine blades under different wind speeds based on the mechanical energy model.
[0135] The power determination unit 902 is used to obtain the mechanical energy captured by the wind turbine blades based on the first curve, and to determine the output power of the wind turbine based on the mechanical energy.
[0136] Curve determination unit 903 is used to determine a second curve of generator speed and output voltage based on the output power of the wind turbine generator;
[0137] The curve fitting unit 904 is used to fit the first curve of generator speed and mechanical energy and the second curve of generator speed and output voltage under different wind speeds to obtain the third curve of wind turbine output voltage and output power.
[0138] The matching unit 905 is used to match the operating mode of the wind turbine system under different operating conditions based on the third curve.
[0139] Based on the same inventive concept, this disclosure also provides an electronic device 161, see [link to previous document]. Figure 10 It includes a processor 164, a communication interface 165, a memory 162, and a communication bus, wherein the processor 164, the communication interface 165, and the memory 162 communicate with each other through the communication bus;
[0140] Memory 162 stores computer program 163;
[0141] When the processor 164 executes the program stored in the memory 162, it implements a control method for an off-grid system of a small wind turbine without a wind speed sensor.
[0142] The aforementioned communication bus can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. This communication bus can be divided into address bus, data bus, control bus, etc.
[0143] The communication interface 165 is used for communication between the aforementioned electronic device 161 and other devices.
[0144] The memory 162 may include random access memory (RAM) or non-volatile memory, such as at least one disk storage device. Optionally, the memory 162 may also be at least one storage device located remotely from the aforementioned processor 164.
[0145] The processor 164 mentioned above can be a general-purpose processor 164, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.
[0146] Based on the same inventive concept, another aspect of the present disclosure provides a computer-readable storage medium storing a computer program 163, which, when executed by a processor 164, implements a control method for an off-grid system of a small wind turbine without a wind speed sensor.
[0147] The computer-readable storage medium may be included in the device / apparatus described in the above embodiments; or it may exist independently and not assembled into the device / apparatus. The computer-readable storage medium carries one or more programs, which, when executed, implement a sensorless small wind turbine off-grid system control method according to an embodiment of the present disclosure.
[0148] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.
Claims
1. A control method for an off-grid system of a small wind turbine generator without a wind speed sensor, characterized in that, include: A mechanical energy model is established based on the wind turbine system and wind turbine blades. Based on the mechanical energy model, the first curve of the generator speed and mechanical energy of the turbine blades under different wind speeds is obtained. The mechanical energy captured by the wind turbine blades is obtained from the first curve, and the output power of the wind turbine is determined based on the mechanical energy. A second curve of generator speed versus output voltage is determined based on the output power of the wind turbine; The first curve of generator speed versus mechanical energy and the second curve of generator speed versus output voltage under different wind speeds are fitted to obtain the third curve of wind turbine output voltage versus output power. The operating mode of the wind turbine system under different operating conditions is matched based on the third curve.
2. The method according to claim 1, characterized in that, The establishment of a mechanical energy model based on the wind turbine system and wind turbine blades includes: A wind power generation system model is established based on the parameters of wind turbine airfoil, wind turbine chord length, wind turbine radius, and wind farm type in the wind turbine system. Mechanical energy is captured based on the wind power generation system model, and a mechanical energy model of the wind power generation system is obtained based on the captured mechanical energy.
3. The method according to claim 1 or 2, characterized in that, The first curve obtained based on the mechanical energy model, which represents the relationship between generator speed and mechanical energy of the generator blades at different wind speeds, includes: Set a wind speed curve, and fit the wind turbine generator speed curve to the wind speed curve. According to the generator speed curve, the generator speed at different wind speeds corresponds to the first curve of the mechanical energy of the wind turbine blades generating the generator speed and the mechanical energy of the turbine blades in the mechanical energy model.
4. The method according to claim 3, characterized in that, The step of obtaining the mechanical energy captured by the wind turbine blades based on the first curve, and determining the output power of the wind turbine based on the mechanical energy, includes: The maximum mechanical energy captured by the wind turbine blades at different wind speeds is obtained from the first curve. The output power of the wind turbine is determined based on the maximum mechanical energy, the first conversion efficiency between the wind turbine blades and the generator, and the second conversion efficiency output by the generator controller.
5. The method according to claim 4, characterized in that, The second curve for determining the generator speed and output voltage based on the output power of the wind turbine includes: The wind turbine's speed curve is determined based on its output power. The curve of the wind turbine's output voltage is determined based on the wind turbine's output power; The output voltage curve of the wind turbine is fitted with the corresponding speed curve of the generator to obtain a second curve of generator speed versus output voltage.
6. The method according to claim 1, characterized in that, The process of fitting the first curve of generator speed versus mechanical energy and the second curve of generator speed versus output voltage under different wind speeds to obtain the third curve of wind turbine output voltage versus output power includes: Based on the rotational speed points in the first curve where the maximum mechanical energy captured by the blades corresponds to the generator speed at different wind speeds, the generator output power is obtained. Based on the rotational speed at which the blade captures the maximum mechanical energy, the wind turbine output voltage is obtained from the second curve; The third curve of wind turbine output voltage versus output power is obtained based on the output power of the generator and the output voltage of the wind turbine.
7. The method according to claim 6, characterized in that, The matching of operating modes of the wind turbine system under different operating conditions based on the third curve includes: The operating conditions are set based on the voltage output after rectification of the generator output voltage in the third curve. Among them, when the output voltage after rectification is lower than the minimum operating voltage, the matching condition is the low wind speed operation condition, and the output power is zero. When the rectified output voltage is greater than the minimum operating voltage, the matching condition is medium to high wind speed operation. At this time, the output power is output according to the output power corresponding to the generator output voltage in the third curve. When the rectified output current is higher than the maximum operating current, the matching condition is the ultra-high wind speed operation condition, and the unloading mode is activated.
8. A sensorless control device for an off-grid system of a small wind turbine generator, characterized in that, include: The model building unit is used to build a mechanical energy model based on the wind turbine system and wind turbine blades, and to obtain the first curve of the generator speed and mechanical energy of the turbine blades under different wind speeds based on the mechanical energy model. A power determination unit is used to obtain the mechanical energy captured by the wind turbine blades based on the first curve, and to determine the output power of the wind turbine based on the mechanical energy. A curve determination unit is used to determine a second curve of generator speed and output voltage based on the output power of the wind turbine generator; The curve fitting unit is used to fit the first curve of generator speed versus mechanical energy and the second curve of generator speed versus output voltage under different wind speeds to obtain the third curve of wind turbine output voltage versus output power. The matching unit is used to match the operating modes of the wind turbine system under different operating conditions based on the third curve.
9. An electronic device, characterized in that, include: The processor, communication interface, memory, and communication bus are connected, with the processor, communication interface, and memory communicating with each other via the communication bus. Memory, which stores computer programs; When the processor executes the program stored in the memory, it implements the sensorless small wind turbine off-grid system control method according to any one of claims 1 to 7.
10. A computer-readable storage medium, characterized in that, The system contains a computer program that, when executed by a processor, implements the sensorless small wind turbine off-grid system control method according to any one of claims 1 to 7.