A method and device for constructing a model of a wind power generation system

Abstract

The application discloses a kind of model construction method and device of wind power generation system, the method wind power generation system, at least including wind turbine and permanent magnet synchronous generator, the method includes: the mechanical characteristics of wind turbine is modeled according to momentum theory data to obtain wind turbine model;Maximum power output point of wind turbine is tracked by analyzing wind turbine model and using hill climbing search method;Ideal conditions met by permanent magnet synchronous generator are obtained;Under ideal conditions, three-phase voltage equation under natural coordinate system, flux linkage equation under natural coordinate system, electromagnetic torque equation of motor, mechanical motion equation of permanent magnet synchronous generator are established to obtain permanent magnet synchronous motor model.The application can reduce the loss generated by mechanical rotation in power generation process, so that the power generation efficiency of system is higher.

Description

Technical Field

[0001] This invention relates to the field of power generation system model building technology, and in particular to a method and apparatus for building a wind power generation system model. Background Technology

[0002] Airflow control in wind farms is a complex problem involving turbine wake, wind farm layout optimization, and interactions between turbines. Researchers are developing various control strategies, such as dynamic wake control, to improve the overall efficiency of wind farms. Building accurate wind power system models is challenging because it requires considering multiple factors, such as wind speed, wind direction, turbulence, and turbine design parameters. Models need to be validated and calibrated using experimental data to ensure their predictive accuracy. The layout of a wind farm has a significant impact on power generation efficiency. Factors such as turbine spacing, wind direction variations, and terrain need to be considered to optimize turbine arrangement, reduce wake losses, and increase the total power generation of the wind farm. Dynamically simulating wind farm behavior is crucial for predicting wind farm performance and developing control strategies. This requires a deep understanding of the aerodynamic, mechanical, and electrical characteristics of wind turbines and the ability to accurately represent these characteristics in the model. Grid connection of wind power presents a series of technical challenges, including grid stability, power quality, power imbalance, grid dynamic response, and transmission planning. The intermittent and unpredictable nature of wind power can increase grid operating costs and affect grid stability and reliability. Accurate wind power forecasting is crucial for grid dispatch and operation. Researchers are developing more advanced wind power forecasting technologies, such as physics-based forecasting models, real-time wind energy data, and computational learning systems, to improve the accuracy of wind power forecasts. Summary of the Invention

[0003] The present invention aims to at least partially solve one of the technical problems in the related art.

[0004] To address this, the present invention proposes a model construction method for wind power generation systems. This method improves the efficiency and reliability of wind power generation systems by optimizing control strategies and operating points, ensuring efficient operation of wind turbine generators under various wind speed conditions.

[0005] To achieve the above objectives, another aspect of the present invention provides a model building device for a wind power generation system.

[0006] To achieve the above objectives, the present invention provides a method for modeling a wind power generation system, wherein the wind power generation system includes at least a wind turbine and a permanent magnet synchronous generator, and the method includes:

[0007] The mechanical characteristics of the wind turbine are modeled based on momentum theory data to obtain the wind turbine model;

[0008] By analyzing the wind turbine model and using the hill-climbing search method, the maximum power output point of the wind turbine was traced.

[0009] To obtain the ideal conditions that a permanent magnet synchronous generator must meet;

[0010] Under the aforementioned ideal conditions, the three-phase voltage equations, flux linkage equations, electromagnetic torque equations of the motor, and mechanical motion equations of the permanent magnet synchronous generator are established in the natural coordinate system to obtain the permanent magnet synchronous motor model.

[0011] The model construction method for the wind power generation system in this embodiment of the invention may also have the following additional technical features:

[0012] In one embodiment of the present invention, a wind turbine model is described as follows:

[0013]

[0014] In the formula: p is the air density, kg / m³ 3 S is the area swept by the rotating blade, in meters. 2 V is the wind speed, m / s; P is the input power, W; R is the radius of the wind turbine rotor, m.

[0015] In one embodiment of the present invention, the actual output power P of the wind power generation system is... m The value is less than the input power P of the fan, and the relationship is expressed as follows:

[0016] P m =C p ×P

[0017] Wind energy utilization coefficient C p In a wind turbine system, the wind energy utilization coefficient C of the wind turbine is... p , is a nonlinear function of the wind turbine blade pitch angle β and the tip speed ratio λ, expressed as follows:

[0018]

[0019] Where λ is the tip speed ratio, representing the state of the fan at different wind speeds, expressed as:

[0020]

[0021] In the formula: w is the angular velocity of the blade rotation, rad / s.

[0022] In one embodiment of the present invention, the output power of the wind turbine is as follows:

[0023]

[0024] In the formula, P NRated output power, W; V in V represents the cut-in wind speed of the wind turbine, in m / s; N The rated wind speed of the wind turbine is v (m / s). out denoted as the cut-out wind speed of the wind turbine, in m / s.

[0025] To achieve the above objectives, a second aspect of this application provides a model building apparatus for a wind power generation system, comprising:

[0026] The wind turbine model building module is used to model the mechanical characteristics of wind turbines based on momentum theory data to obtain wind turbine models;

[0027] The maximum power analysis module is used to trace the maximum power output point of the wind turbine by analyzing the wind turbine model and using a hill-climbing search method.

[0028] The ideal condition determination module is used to obtain the ideal conditions that the permanent magnet synchronous generator must meet.

[0029] The permanent magnet synchronous motor model building module is used to establish the three-phase voltage equations, flux linkage equations, electromagnetic torque equations of the motor, and mechanical motion equations of the permanent magnet synchronous generator in the natural coordinate system under the ideal conditions to obtain the permanent magnet synchronous motor model.

[0030] This invention provides a method and apparatus for modeling a wind power generation system. It improves the efficiency and reliability of the wind power generation system by optimizing control strategies and operating points, ensuring efficient operation of the wind turbine generator under various wind speed conditions. It also enhances the adaptability and flexibility of the wind turbine generator by adjusting operating parameters in real time to adapt to changes in wind speed and grid demands.

[0031] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0032] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0033] Figure 1 This is a flowchart of a model construction method for a wind power generation system according to an embodiment of the present invention;

[0034] Figure 2 This is a structural diagram of a wind power generation system according to an embodiment of the present invention;

[0035] Figure 3 This is a graph showing the relationship between the wind energy utilization coefficient and the tip speed ratio according to an embodiment of the present invention.

[0036] Figure 4 This is a graph showing the relationship between the output power of a wind turbine generator and the angular velocity of its blades according to an embodiment of the present invention.

[0037] Figure 5 This is a schematic diagram of the tip speed ratio control principle according to an embodiment of the present invention;

[0038] Figure 6 This is a schematic diagram of the power curve method control principle according to an embodiment of the present invention;

[0039] Figure 7 This is a control flowchart of the hill-climbing search method according to an embodiment of the present invention;

[0040] Figure 8 This is a schematic diagram of a model building device for a wind power generation system according to an embodiment of the present invention. Detailed Implementation

[0041] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0042] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0043] The following description, with reference to the accompanying drawings, illustrates a method and apparatus for constructing a model of a wind power generation system according to an embodiment of the present invention.

[0044] Figure 1 This is a flowchart of a model construction method for a wind power generation system according to an embodiment of the present invention, such as... Figure 1 As shown, a wind power generation system includes at least a wind turbine and a permanent magnet synchronous generator, and the method includes:

[0045] S1, The mechanical characteristics of the wind turbine are modeled based on momentum theory data to obtain the wind turbine model;

[0046] S2, by analyzing the wind turbine model and using the hill-climbing search method to trace the maximum power output point of the wind turbine;

[0047] S3, to obtain the ideal conditions satisfied by the permanent magnet synchronous generator;

[0048] S4. Under the ideal conditions, establish the three-phase voltage equation in the natural coordinate system, the flux linkage equation in the natural coordinate system, the electromagnetic torque equation of the motor, and the mechanical motion equation of the permanent magnet synchronous generator to obtain the permanent magnet synchronous motor model.

[0049] Specifically, wind turbines can be classified into two main categories based on the installation method of their rotor shafts: horizontal axis wind turbines and vertical axis wind turbines. Compared to horizontal axis wind turbines, vertical axis wind turbines have significant advantages in power generation efficiency, wind resistance, and starting wind speed. According to the power regulation method, wind turbines can be divided into constant pitch stall and variable pitch types; according to the operating characteristics of the wind turbine generator, they can be divided into constant speed, finite speed, and variable speed types. This invention selects to study the mathematical model of a variable speed, variable pitch vertical axis wind turbine, and the generator selected is a permanent magnet synchronous generator. Its wind power generation system structure diagram is shown below. Figure 2 As shown.

[0050] from Figure 2 As can be seen, a wind power generation system includes a wind turbine, a synchronous generator, a rectifier, an inverter, and a controller. Compared with other wind power generation systems, the permanent magnet synchronous generator connects the wind turbine directly to the generator without an intermediate transmission device, which reduces the losses caused by mechanical rotation during power generation and makes the system more efficient.

[0051] The working principle of the wind turbine in this embodiment of the invention is that wind energy is converted into mechanical energy by driving the blades to rotate. Therefore, by modeling the mechanical characteristics of the wind turbine according to momentum theory, a mathematical model of its output power can be obtained:

[0052]

[0053] In the formula: p is the air density, kg / m³ 3 S is the area swept by the rotating blade, in meters. 2 V is the wind speed, m / s; P is the input power, W; R is the radius of the wind turbine rotor, m.

[0054] When wind passes through the blades of a wind turbine, the blades can only utilize a portion of the wind energy to convert it into electrical energy, not all of it. Therefore, the actual output power P of a wind power generation system is limited. m The power must be less than the input power P of the fan, and the relationship can be expressed as follows:

[0055] P m =C p ×P

[0056] The coefficient between output power and input power is usually called the wind energy utilization coefficient C. p In a wind turbine system, the wind energy utilization coefficient C of the wind turbine is... p, is a nonlinear function of the wind turbine blade pitch angle β and the tip speed ratio λ, expressed as follows:

[0057]

[0058] Where λ is the tip speed ratio, representing the state of the fan at different wind speeds, expressed as:

[0059]

[0060] In the formula: w is the angular velocity of the blade rotation, rad / s.

[0061] Based on the above formula, the wind energy utilization coefficient C can be obtained. p The graph showing the correspondence between the blade tip speed ratio λ and the tip speed ratio is as follows: Figure 3 As shown.

[0062] Since wind speed is not constant, the output power of a wind turbine will change accordingly under different operating conditions. The specific output performance can be summarized as follows:

[0063]

[0064] In the formula, P N Rated output power, W; V in V represents the cut-in wind speed of the wind turbine, in m / s; N The rated wind speed of the wind turbine is v (m / s). out denoted as the cut-out wind speed of the wind turbine, in m / s.

[0065] Furthermore, Figure 4 The graph shows the relationship between the output power of a wind turbine and the rotational angular velocity of its blades as wind speeds range from 4 m / s to 10 m / s. It can be seen from the graph that, under constant wind speed, the wind turbine's output power is maximized when its rotational speed equals the speed corresponding to the optimal tip speed ratio. As wind speed changes, the optimal tip speed ratio also changes, thus altering both the rotational speed and the maximum output power.

[0066] Therefore, in order to ensure that wind turbines can always maintain maximum power output during operation, the concept of maximum power output point tracking (MPOP) was proposed. Currently, there are three commonly used MPOP methods: tip speed ratio method, power curve method, and hill-climbing search method.

[0067] The tip speed ratio method controls the tip speed ratio to always be at its optimal state, so that the wind turbine's output power remains at maximum, thereby achieving maximum power output point tracking. Its control principle is as follows: Figure 5 As shown.

[0068] The power curve method uses the power curve provided by the manufacturer when the wind turbine is manufactured as a basis for judgment. It compares the actual output power at the current wind speed with the rated output power, feeds the difference back to the wind turbine, and then adjusts the turbine accordingly to ensure it operates at maximum power. Its control principle is as follows: Figure 6 As shown.

[0069] The hill-climbing search method is relatively simple among the three methods. This method automatically searches for the optimal speed point based on power changes by introducing artificial disturbances, thereby achieving the goal of maximum power output point tracking. Its control flow is as follows: Figure 7 As shown.

[0070] Based on the study and comparison of the above three maximum power output point tracking control methods, this invention selects the hill-climbing search method for the study of wind turbines.

[0071] In wind power generation systems, three-phase permanent magnet synchronous motors are selected as the generators. Compared to other high-speed motors, the wind turbine of a wind turbine does not rotate very fast in natural wind. However, in order to enable the generator to output greater power at lower speeds, the number of pole pairs can be increased. At the same time, choosing a direct-drive method can reduce the mechanical losses caused by gear transmission, resulting in higher system power generation efficiency.

[0072] In establishing the mathematical model of the permanent magnet synchronous generator, for the sake of simplicity in calculation and analysis, this invention assumes that the permanent magnet synchronous generator under study is the most ideal model: (1) the influence of magnetic circuit saturation is ignored; (2) the current presents a standard sine wave without the influence of harmonics; (3) eddy current loss and hysteresis loss in the motor are ignored; (4) the resistance of the windings inside the motor remains unchanged and is not affected by external conditions such as temperature. The mathematical model of the permanent magnet synchronous generator when the above conditions are met is as follows:

[0073] Three-phase voltage equations in natural coordinates:

[0074]

[0075] In the formula: u 3s Phase voltage of the three-phase winding, V; 3s Phase current of three-phase winding, A; R 3s Resistance of the three-phase winding, Ω; ψ 3s The flux linkage of the phase winding, Wb.

[0076] And it can be represented in the following form:

[0077]

[0078] After sorting, we get:

[0079]

[0080] The flux linkage equation in natural coordinates:

[0081] ψ 3s =L 3s i 3s +φ·F 3s (θ e )

[0082] In the formula: L 3s Inductance of the three-phase winding, H; F 3s (θ e The flux linkage of the three-phase winding, Wb.

[0083] And it can be represented in the following form:

[0084]

[0085] The electromagnetic torque equation of an electric motor:

[0086] Based on the principle of electromechanical energy conversion, the formula for calculating the electromagnetic torque T of a motor is as follows:

[0087]

[0088] In the formula: p n denoted as the number of pole pairs in a permanent magnet generator.

[0089] The mechanical motion equations of a permanent magnet synchronous generator:

[0090]

[0091] Where: J is the moment of inertia of the motor, kg·m 2 ;T L The load torque of the motor, N·m; B; the damping coefficient of the motor; ω m —The mechanical angular velocity of the motor, in rad / s.

[0092] The model construction method for a basic wind power generation system according to embodiments of the present invention improves the efficiency and reliability of the wind power generation system. By optimizing control strategies and operating points, it ensures that the wind turbine generator can operate efficiently under various wind speed conditions. It enhances the adaptability and flexibility of the wind turbine generator by adjusting operating parameters in real time to adapt to wind speed changes and grid demands. It improves the stability and safety of the wind turbine generator by reducing mechanical stress and fatigue damage and extending equipment life through accurate models and control strategies. It optimizes the design and manufacturing of the wind turbine generator by deeply understanding the physical characteristics and operating behavior of the motor, guiding the design and improvement of new wind turbine generators.

[0093] like Figure 8As shown, the present invention also proposes a power generation calculation device 10 based on a renewable energy integrated utilization system, comprising:

[0094] The wind turbine model building module 100 is used to model the mechanical characteristics of the wind turbine based on momentum theory data to obtain a wind turbine model;

[0095] The maximum power analysis module 200 is used to trace the maximum power output point of the wind turbine by analyzing the wind turbine model and using a hill-climbing search method.

[0096] Ideal condition determination module 300 is used to obtain the ideal conditions satisfied by the permanent magnet synchronous generator;

[0097] The permanent magnet synchronous motor model building module 400 is used to establish the three-phase voltage equations, flux linkage equations, electromagnetic torque equations of the motor, and mechanical motion equations of the permanent magnet synchronous generator in the natural coordinate system under the ideal conditions to obtain the permanent magnet synchronous motor model.

[0098] Furthermore, wind turbine model:

[0099]

[0100] In the formula: p is the air density, kg / m³ 3 S is the area swept by the rotating blade, in meters. 2 V is the wind speed, m / s; P is the input power, W; R is the radius of the wind turbine rotor, m.

[0101] Furthermore, the actual output power P of the wind power generation system m The value is less than the input power P of the fan, and the relationship is expressed as follows:

[0102] P m =C p ×P

[0103] Wind energy utilization coefficient C p In a wind turbine system, the wind energy utilization coefficient C of the wind turbine is... p , is a nonlinear function of the wind turbine blade pitch angle β and the tip speed ratio λ, expressed as follows:

[0104]

[0105] Where λ is the tip speed ratio, representing the state of the fan at different wind speeds, expressed as:

[0106]

[0107] In the formula: w is the angular velocity of the blade rotation, rad / s.

[0108] Furthermore, the output power of a wind turbine is as follows:

[0109]

[0110] In the formula, P N Rated output power, W; V in V represents the cut-in wind speed of the wind turbine, in m / s; N The rated wind speed of the wind turbine is v (m / s). out denoted as the cut-out wind speed of the wind turbine, in m / s.

[0111] The model building apparatus for a basic wind power generation system according to embodiments of the present invention improves the efficiency and reliability of the wind power generation system. By optimizing control strategies and operating points, it ensures that the wind turbine generator can operate efficiently under various wind speed conditions. It enhances the adaptability and flexibility of the wind turbine generator by adjusting operating parameters in real time to adapt to wind speed changes and grid demands. It improves the stability and safety of the wind turbine generator by reducing mechanical stress and fatigue damage and extending equipment life through accurate models and control strategies. It optimizes the design and manufacturing of the wind turbine generator by providing a deep understanding of the physical characteristics and operating behavior of the motor, guiding the design and improvement of new wind turbine generators.

[0112] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0113] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

Claims

1. A method for modeling a wind power generation system, characterized in that, The wind power generation system includes at least a wind turbine and a permanent magnet synchronous generator, and the method includes: The mechanical characteristics of the wind turbine are modeled based on momentum theory data to obtain the wind turbine model; By analyzing the wind turbine model and using the hill-climbing search method, the maximum power output point of the wind turbine was traced. To obtain the ideal conditions that a permanent magnet synchronous generator must meet; Under the aforementioned ideal conditions, the three-phase voltage equations, flux linkage equations, electromagnetic torque equations of the motor, and mechanical motion equations of the permanent magnet synchronous generator are established in the natural coordinate system to obtain the permanent magnet synchronous motor model.

2. The method according to claim 1, characterized in that, Wind turbine model: In the formula: p is the air density, kg / m³ 3 S is the area swept by the rotating blade, in meters. 2 V represents wind speed, in m / s; P is the input power, W; R is the radius of the wind turbine rotor, m.

3. The method according to claim 2, characterized in that, The actual output power P of the wind power generation system m The value is less than the input power P of the fan, and the relationship is expressed as follows: P m =C p ×P Wind energy utilization coefficient C p In a wind turbine system, the wind energy utilization coefficient C of the wind turbine is... p , is a nonlinear function of the wind turbine blade pitch angle β and the tip speed ratio λ, expressed as follows: Where λ is the tip speed ratio, representing the state of the fan at different wind speeds, expressed as: In the formula: w is the angular velocity of the blade rotation, rad / s.

4. The method according to claim 3, characterized in that, The output power of a wind turbine is as follows: In the formula, P N Rated output power, W; V in V represents the cut-in wind speed of the wind turbine, in m / s; N The rated wind speed of the wind turbine is v (m / s). out denoted as the cut-out wind speed of the wind turbine, in m / s.

5. A model building device for a wind power generation system, characterized in that, The wind power generation system includes at least a wind turbine and a permanent magnet synchronous generator, and the method includes: The wind turbine model building module is used to model the mechanical characteristics of wind turbines based on momentum theory data to obtain wind turbine models; The maximum power analysis module is used to trace the maximum power output point of the wind turbine by analyzing the wind turbine model and using a hill-climbing search method. The ideal condition determination module is used to obtain the ideal conditions that the permanent magnet synchronous generator must meet. The permanent magnet synchronous motor model building module is used to establish the three-phase voltage equations, flux linkage equations, electromagnetic torque equations of the motor, and mechanical motion equations of the permanent magnet synchronous generator in the natural coordinate system under the ideal conditions to obtain the permanent magnet synchronous motor model.

6. The apparatus according to claim 5, characterized in that, Wind turbine model: In the formula: p is the air density, kg / m³ 3 S is the area swept by the rotating blade, in meters. 2 V represents wind speed, in m / s; P is the input power, W; R is the radius of the wind turbine rotor, m.

7. The apparatus according to claim 6, characterized in that, The actual output power of the wind power generation system O m The value is less than the input power P of the fan, and the relationship is expressed as follows: P m =C p ×P Wind energy utilization coefficient C p In a wind turbine system, the wind energy utilization coefficient C of the wind turbine is... p , is a nonlinear function of the wind turbine blade pitch angle β and the tip speed ratio λ, expressed as follows: Where λ is the tip speed ratio, representing the state of the fan at different wind speeds, expressed as: In the formula: w is the angular velocity of the blade rotation, rad / s.

8. The apparatus according to claim 7, characterized in that, The output power of a wind turbine is as follows: In the formula, P N Rated output power, W; V in V represents the cut-in wind speed of the wind turbine, in m / s; N The rated wind speed of the wind turbine is v (m / s). out denoted as the cut-out wind speed of the wind turbine, in m / s.

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