Wind power primary frequency modulation method and system based on combined load shedding of rotating speed and pitch angle

Abstract

The invention discloses a wind power primary frequency modulation method and system based on rotation speed and pitch angle combined load shedding, and the method comprises the steps: calculating a rotation speed load shedding suboptimal power tracking curve when a pitch angle is fixed; under the medium-low wind speed condition, the obtained rotating speed load shedding suboptimal power tracking curve is used for achieving rotating speed load shedding; calculating a wind speed-pitch angle curve; under the high wind speed condition, the obtained wind speed-pitch angle curve is used for achieving pitch angle load shedding; and realizing combined primary frequency modulation control on the rotating speed and the pitch angle of the doubly-fed fan based on pitch angle load shedding. Advantage intervals of two load shedding frequency modulation modes are brought into full play, and the problems that rotating speed load shedding cannot be used for a high-wind-speed interval, and pitch angle load shedding is low in response speed and needs frequent actions are solved.

Description

Background Art

[0002] Against the backdrop of a weak power grid in the northwest region, the frequency issues brought about by the access of a large number of new energy sources have become increasingly prominent. A high proportion of new energy sources are connected to the weak power grid at the sending end, large-scale DC projects are transmitted, new energy fluctuations, DC faults and other issues impact the power grid frequency, resulting in a serious lack of peak-shaving and frequency regulation capabilities. At the same time, due to the absence of large conventional units and generally low short-circuit ratios, weak power grids have the characteristics of weak synchronous support and poor frequency anti-disturbance capabilities, and have greater stability risks. Therefore, the participation of new energy sites in primary frequency regulation is an important way to solve the stability problems brought about by a high proportion of new energy sources, and it is also an important trend at present. Compared with the primary frequency regulation method of conventional units, the primary frequency regulation of new energy sources has the advantages of fast response speed, high precision, flexible control and low regulation cost.

[0003] In order to ensure the safe and stable operation of high-proportion wind power systems, the primary frequency regulation capability of wind turbines is generally increased by adding control links. This method requires sufficient energy regulation sources for the primary frequency regulation response of wind turbines. The energy supply methods usually include additional energy storage and load shedding standby. Additional energy storage mainly participates in the system frequency response through energy storage media such as energy storage batteries and supercapacitors. Load shedding standby is a method of reducing the wind energy capture coefficient through overspeed control and pitch control, so that the wind turbine operates at the suboptimal power tracking point, thereby obtaining a certain amount of active power reserve. According to the principle, it can be divided into pitch angle load shedding and speed load shedding. Pitch angle load shedding increases the pitch angle to allow the unit to reserve active power for primary frequency regulation; speed load shedding is to increase the rotor speed when the wind turbine is running on the MPPT curve to make the working point of the wind turbine deviate from the MPP, so that the unit reserves spare capacity for primary frequency regulation.

[0004] However, the two methods of load shedding standby have their own applicable ranges. Speed ​​shedding achieves the purpose of active power standby through overspeed control. When the wind speed is high, speed shedding is more harmful to the mechanical structure of the unit, so it is generally used in medium and low wind speeds. Pitch angle shedding completes active power standby through variable pitch control and is suitable for a larger wind speed range. However, since variable pitch control involves mechanical parts, the response speed is slow, and if the action is too frequent, it is easy to aggravate the wear of the mechanical structure and reduce the service life of the wind turbine. Therefore, the two methods of load shedding standby each have their own advantages and disadvantages, and it is difficult to achieve a good primary frequency regulation effect when used alone. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a wind power primary frequency regulation method and system based on joint load reduction of speed and pitch angle in response to the above-mentioned deficiencies in the prior art, so as to solve the technical problem that speed reduction or pitch angle load reduction alone is difficult to be applied to both high wind speed range and medium and low wind speed range, and the primary frequency regulation of the doubly fed wind turbine is only applicable to a small wind speed range.

[0006] The present invention adopts the following technical solutions: The wind power primary frequency regulation method based on the combined load reduction of rotation speed and pitch angle comprises the following steps: S1. Calculate the speed reduction suboptimal power tracking curve at a fixed pitch angle; S2. Under low to medium wind speed conditions, speed reduction is achieved using the speed reduction optimal power tracking curve obtained in step S1; S3, calculating the wind speed-pitch angle curve; S4, using the wind speed-pitch angle curve obtained in step S3 to achieve pitch angle load reduction under high wind speed conditions; S5. Based on the pitch angle load reduction in step S4, the rotation speed and pitch angle of the doubly-fed wind turbine are controlled in conjunction with primary frequency regulation.

[0007] Preferably, step S1 specifically includes: Calculate the wind speed range within which the wind turbine can operate and the pitch angle i When the value is 0, different wind speeds V w The fan absorbed power P changes with the fan speed oh r Changing curves to get different wind speeds V w The maximum absorbed power of the fan is obtained, and then the maximum power tracking curve under the rated power of the fan is obtained. oh r -Max_P, and the wind speed when the wind turbine absorbs rated power when the pitch angle is 0 and the speed is at the maximum value V w_MaxP ; According to the maximum power tracking curve under the rated power of the fan oh r -Max_P calculates the load reduction power Del_P corresponding to different wind speeds when the load reduction rate is d%, and obtains the rotor speed upper limit Max oh r The following load shedding power curve oh r -Del_P( oh r ); According to the load shedding power curve oh r -Del_P( oh r ), calculate the fan absorbed power Del_P_Max when the rotor speed reaches the upper limit oh r , and the wind speed at this time V w_Delωr, the maximum wind speed and wind turbine absorbed power that can meet the load reduction rate of d% by speed reduction are obtained, and this is used as the threshold for switching the pitch angle to reduce load. According to the load reduction power curve oh r -Del_P( oh r ) and fitted the speed reduction suboptimal power tracking curve Del_P- oh r (P).

[0008] Preferably, in step S2, according to the speed reduction suboptimal power tracking curve Del_P- oh r (P), set speed suboptimal power reduction; When the total active power P output by the double-fed wind turbine is detected out Less than the threshold Del_P_Max oh r When the speed is reduced, the active power reserve is provided for the primary frequency regulation; When the total active power P output by the double-fed wind turbine is detected out Greater than Del_P_Max oh r When , the speed load reduction is switched to pitch angle load reduction.

[0009] Preferably, when the total active power P output by the doubly-fed wind turbine is detected out Less than the threshold Del_P_Max oh r When the rotor speed command value is oh r_ref =Del_P- oh r (P out );When the total active power P output by the doubly fed wind turbine is detected out Greater than Del_P_Max oh r When the rotor speed command value is oh r_ref =Max oh r .

[0010] Preferably, step S3 specifically includes: According to the corresponding curve of wind speed and load reduction power V w -P( V w ) and the corresponding curve of pitch angle and power i -P( i ), the wind speed is [ V w_Delωr , Vw_MaxP ] interval, the corresponding curve of wind speed and pitch angle V w -θ 1( V w ); When the wind speed is [ V w_MaxP , V w_ max ]hour, V w_ max To cut out the wind speed, the absorbed power of the double-fed wind turbine after load reduction reaches 1-d% times the rated value. V w -P( V w ) curve and i -P( i ) curve to calculate the wind speed and pitch angle corresponding curve V w –θ 2( V w ).

[0011] Preferably, the wind speed is [ V w_Delωr , V w_MaxP ] interval, the wind turbine absorbs power and follows the load reduction power, and the corresponding curve of pitch angle and power is i -P( i ); According to the maximum power tracking curve under the rated power of the fan oh r -Max_P, calculated load reduction rate d%, wind speed is [ V w_Delωr , V w_MaxP ] interval, the corresponding curve of wind speed and load reduction power V w -P( V w ).

[0012] Preferably, in step S4, according to the two wind speed-pitch angle curves obtained in step S3, V w_MaxP The pitch angle is set as the threshold for suboptimal power reduction. When the wind speed is detected to be [ V w_Delωr , V w_MaxP ] interval, according to the curve V w -θ 1( Vw ),make θ= i 1( V w ), as the pitch angle command value i ref part of the pitch angle command value. i ref middle; When the wind speed is [ V w_MaxP , V w_ max ] interval, let θ=θ 2( V w ) is added to the pitch angle command value i ref .

[0013] Preferably, step S5 is specifically: Detect the frequency deviation of adjacent thermal power units oh , as the controlled variable of speed frequency modulation and pitch angle frequency modulation, after passing through the low-pass filter and dead zone limit, it is multiplied by the negative droop coefficient K oh r Add to the torque command value T of the double-fed fan e_ref middle; Set the pitch angle droop control coefficient K to a positive value θ , the speed deviation after dead zone and filtering d oh Multiply by K θ Then add it to the pitch angle command value of the doubly fed wind turbine i ref middle; Take the speed closed-loop control and use PI adjustment to reduce the speed reference value oh r_ref Used to control the rotor speed. The PI link output is added to the speed frequency modulation result to generate the reference value T of the electromagnetic torque control loop. e_ref , used for rotor side current control; Generates pitch angle control angle signal for wind turbine control.

[0014] Preferably, the angle signal for pitch angle control includes pitch control, pitch compensation, pitch angle frequency modulation and pitch angle compensation.

[0015] In a second aspect, an embodiment of the present invention provides a wind power primary frequency regulation system based on combined load reduction of rotation speed and pitch angle, comprising: Curve module, which calculates the speed-reduced suboptimal power tracking curve at a fixed pitch angle; The first load shedding module uses the speed shedding optimal power tracking curve to achieve speed shedding under medium and low wind speed conditions; A calculation module, which calculates the wind speed-pitch angle curve; A second load reduction module, using the obtained wind speed-pitch angle curve to achieve pitch angle load reduction under high wind speed conditions; The control module realizes the joint primary frequency regulation control of the speed and pitch angle of the doubly-fed wind turbine based on the pitch angle load reduction.

[0016] In a third aspect, a computer device comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above-mentioned method for primary frequency regulation of wind power based on combined load reduction of rotation speed and pitch angle when executing the computer program.

[0017] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, including a computer program, which, when executed by a processor, implements the steps of the above-mentioned wind power primary frequency regulation method based on joint load reduction of rotation speed and pitch angle.

[0018] In a fifth aspect, a chip comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above-mentioned wind power primary frequency regulation method based on joint load reduction of rotation speed and pitch angle when executing the computer program.

[0019] In a sixth aspect, an embodiment of the present invention provides an electronic device, including a computer program, which, when executed by the electronic device, implements the steps of the above-mentioned wind power primary frequency regulation method based on joint load reduction of rotation speed and pitch angle.

[0020] Compared with the prior art, the present invention has at least the following beneficial effects: A wind power primary frequency regulation method based on joint load reduction of speed and pitch angle combines speed load reduction and pitch angle load reduction. Speed ​​load reduction is adopted in medium and low wind speed ranges, and pitch angle load reduction is adopted in high wind speed ranges. This ensures that the doubly fed wind turbine has a certain spare capacity for primary frequency regulation under various wind speed conditions. A good primary frequency regulation effect is achieved through the coordinated work of speed frequency regulation and pitch angle frequency regulation.

[0021] Furthermore, under low and medium wind speed conditions, a suboptimal power tracking curve is calculated based on the maximum power tracking curve, which provides a basis for subsequent speed reduction.

[0022] Furthermore, under medium and low wind speed conditions, speed reduction is adopted to provide primary frequency regulation reserve capacity without changing the pitch angle, thereby reducing the number of actions of the variable pitch control system; speed frequency regulation is adopted for primary frequency regulation, which has a fast response speed.

[0023] Furthermore, under high wind speed conditions, the pitch angle suboptimal power load reduction curve is calculated based on the corresponding curve of pitch angle and power at a constant maximum rotor speed, which provides a basis for subsequent pitch angle load reduction.

[0024] Furthermore, under high wind speed conditions, pitch angle frequency modulation is adopted to provide primary frequency regulation reserve capacity. When the speed reaches the maximum and cannot provide sufficient reserve capacity, pitch angle frequency modulation is used to supplement the reserve capacity. When the wind speed reaches a certain level and speed reduction cannot provide reserve capacity, pitch angle load reduction is fully utilized to provide sufficient reserve capacity, which significantly expands the wind speed range of the doubly fed wind turbine participating in primary frequency regulation.

[0025] Furthermore, on the basis of jointly reducing the speed and pitch angle to obtain sufficient primary frequency regulation reserve capacity, the speed frequency regulation and pitch angle frequency regulation cooperate with each other to achieve a good primary frequency regulation effect.

[0026] It can be understood that the beneficial effects of the second to sixth aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here.

[0027] In summary, the present invention combines speed reduction and pitch angle reduction to form a new suboptimal joint load reduction method, which gives full play to the advantages of the two load reduction and frequency modulation methods, and overcomes the problems that speed reduction cannot be used in high wind speed ranges, and that pitch angle reduction has a slow response speed and requires frequent actions. Speed ​​reduction is used in medium and low wind speed ranges, and pitch angle reduction is used in high wind speed ranges, ensuring that the doubly fed wind turbine has a certain amount of spare capacity for primary frequency modulation under various wind speed conditions.

[0028] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0030] Figure 1 This is a flow chart of primary frequency regulation for combined load reduction of speed and pitch angle; Figure 2 It is the speed control block diagram; Figure 3 It is the pitch angle control block diagram; Figure 4 This is a diagram of the primary frequency regulation system of the thermal power unit and the fan; Figure 5This is a comparison chart of the load reduction and frequency regulation effects of the rotation speed and pitch angle combined at low wind speed; Figure 6 This is a comparison chart of the load reduction and frequency regulation effects of the rotation speed and pitch angle combined at medium wind speed; Figure 7 This is a comparison chart of the load shedding and frequency regulation effects of high wind speed rotation speed and pitch angle; Figure 8 A schematic diagram of a computer device provided by an embodiment of the present invention; Figure 9 The block diagram of a chip provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] In the description of the present invention, it should be understood that the terms “include” and “comprises” indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0033] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0034] It should be further understood that the term "and / or" used in the present specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects are in an "or" relationship.

[0035] It should be understood that, although the terms first, second, third, etc. may be used to describe preset ranges, etc. in the embodiments of the present invention, these preset ranges should not be limited to these terms. These terms are only used to distinguish preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0036] The word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0037] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0038] The present invention provides a wind power primary frequency regulation method based on joint load reduction of rotational speed and pitch angle, combines rotational speed load reduction and pitch angle load reduction to form a new suboptimal joint load reduction method, gives full play to the advantages of the two load reduction and frequency regulation methods, overcomes the problems that rotational speed load reduction cannot be used in high wind speed ranges, and that pitch angle load reduction has a slow response speed and requires frequent actions; rotational speed load reduction is used in medium and low wind speed ranges, and pitch angle load reduction is used in high wind speed ranges, thereby ensuring that the doubly fed wind turbine has a certain spare capacity for primary frequency regulation under various wind speed conditions.

[0039] See also Figure 1 The present invention provides a wind power primary frequency regulation method based on combined load reduction of rotation speed and pitch angle, comprising the following steps: S1. Calculate the speed reduction suboptimal power tracking curve at a fixed pitch angle; According to the wind speed range in which the fan can operate, use the fan absorption power formula , calculate the fixed pitch angle (pitch angle) within this range i =0), different wind speeds V w The fan absorbed power P changes with the fan speed oh r The changing curves and the different wind speeds can be obtained according to these curves. V w The maximum absorbed power of the wind turbine and its corresponding pitch angle are used to obtain a maximum power tracking (MPPT) curve at the rated power of the wind turbine. oh r -Max_P, and the wind speed when the wind turbine absorbs rated power when the pitch angle is 0 and the speed is at the maximum value V w_MaxP .

[0040] According to the MPPT curve, the load reduction power Del_P corresponding to different wind speeds when the load reduction rate is d% is calculated, and the upper limit Max of the rotor speed is obtained oh r The following load shedding power curve oh r -Del_P( oh r ).

[0041] According to the load reduction power curve, calculate the fan absorbed power Del_P_Max when the rotor speed reaches the upper limit oh r , and the wind speed at this time V w_Delωr , that is, the maximum wind speed and wind turbine absorption power that can meet the d% load reduction rate by speed reduction alone, and use this as the threshold for switching pitch angle load reduction, and according to the load reduction power curve oh r -Del_P( oh r ) and obtain the suboptimal power tracking curve Del_P- oh r (P).

[0042] S2. Under low to medium wind speed conditions, speed reduction is achieved using the speed reduction optimal power tracking curve obtained in step S1; Medium and low wind speed refers to a wind speed greater than the cut-in wind speed of the double-fed wind turbine and less than the wind speed calculated in step S1. V w_MaxP The wind speed range.

[0043] The suboptimal power tracking curve Del_P- oh r (P), set the speed suboptimal power load reduction, and detect the total active power P output of the double-fed wind turbine out Less than the threshold Del_P_Max oh r When the speed is reduced, the load is reduced to provide active power for the primary frequency modulation, so that the rotor speed command value oh r_ref =Del_P- oh r (P out ), when P out Greater than Del_P_Max oh r When the load shedding is switched from speed shedding to pitch shedding, the rotor speed command value is set to a certain value, that is, oh r_ref =Max ohr .

[0044] S3, calculating the wind speed-pitch angle curve; According to the fan absorption power formula , calculate the rotor constant maximum speed, the wind speed is [ V w_Delωr , V w_MaxP ] interval, the wind turbine absorbs power and follows the load reduction power, and the corresponding curve of pitch angle and power is i -P( i ).

[0045] According to the MPPT curve oh r -Max_P, calculated load reduction rate d%, wind speed is [ V w_Delωr , V w_MaxP ] interval, the corresponding curve of wind speed and load reduction power V w -P( V w ).

[0046] According to the corresponding curve of wind speed and load reduction power V w -P( V w ) and the corresponding curve of pitch angle and power i -P( i ), the wind speed is [ V w_Delωr , V w_MaxP ] interval, the corresponding curve of wind speed and pitch angle Vw - θ 1( V w ). When the wind speed is [ V w_MaxP , V w_ max ]hour( V w_ max To cut out the wind speed, the wind turbine will be shut down above this wind speed to protect the wind turbine). After the load is reduced, the absorbed power of the doubly fed wind turbine reaches 1-d% times the rated value. Similarly, the wind speed range can be adjusted according to the wind speed. V w -P( V w ) curve and i -P( i ) curve to calculate the wind speed and pitch angle corresponding curve V w – i 2( V w).

[0047] S4, using the wind speed-pitch angle curve obtained in step S3 to achieve pitch angle load reduction under high wind speed conditions; High wind speed refers to a wind speed greater than the wind speed calculated in step S1. V w_MaxP , less than the cut-out wind speed of the doubly fed wind turbine V w_ max interval.

[0048] According to the two wind speed-pitch angle curves obtained in the above steps, V w_MaxP The pitch angle is set as the threshold for suboptimal power reduction. When the wind speed is detected to be [ V w_Delωr , V w_MaxP ] interval, according to the curve V w -θ 1( V w ),make θ=θ 1( V w ), as the pitch angle command value i ref part of the pitch angle command value. i ref Similarly, when the wind speed is [ V w_MaxP , V w_ max ] interval, let θ=θ 2( V w ) is accumulated to the pitch angle command value i ref .

[0049] S5. Based on the pitch angle load reduction obtained in step S4, the rotation speed and pitch angle of the doubly-fed wind turbine are controlled in conjunction with primary frequency regulation.

[0050] S501, speed frequency modulation First, detect the frequency deviation d of the adjacent thermal power units oh , as the controlled variable of speed frequency modulation and pitch angle frequency modulation, after passing through the low-pass filter and dead zone limit, it is multiplied by the negative droop coefficient K oh r Add to the torque command value T of the double-fed fan e_ref middle.

[0051] S502, pitch angle frequency modulation Set the pitch angle droop control coefficient K to a positive value θ , the speed deviation after dead zone and filtering d oh Multiply by Kθ Then add it to the pitch angle command value of the doubly fed wind turbine i ref middle.

[0052] S503, speed control See also Figure 2 The speed control adopts the speed closed-loop control, and uses the PI adjustment method to reduce the speed reference value oh r_ref Used to control the rotor speed. The PI link output is added to the speed frequency modulation result to generate the reference value T of the electromagnetic torque control loop. e_ref , used for subsequent rotor side current control.

[0053] S504, pitch angle control See also Figure 3 The pitch angle control consists of four parts: pitch control, pitch compensation, pitch angle frequency modulation, and pitch angle compensation. The outputs of the four parts are added together to generate an angle signal for pitch angle control, which is used for wind turbine control.

[0054] It will be appreciated by those skilled in the art that various aspects of the present invention may be implemented as systems, methods or program products. Therefore, various aspects of the present invention may be specifically implemented in the following forms, namely: complete hardware implementation, complete software implementation (including firmware, microcode, etc.), or a combination of hardware and software implementations, which may be collectively referred to herein as "circuits", "modules" or "platforms".

[0055] In another embodiment of the present invention, a wind power primary frequency regulation system based on combined load reduction of rotational speed and pitch angle is provided. The system can be used to implement the above-mentioned wind power primary frequency regulation method based on combined load reduction of rotational speed and pitch angle. Specifically, the wind power primary frequency regulation system based on combined load reduction of rotational speed and pitch angle includes a curve module, a first load reduction module, a calculation module, a second load reduction module and a control module.

[0056] Among them, the curve module calculates the speed reduction suboptimal power tracking curve at a fixed pitch angle; The first load shedding module uses the speed shedding optimal power tracking curve to achieve speed shedding under medium and low wind speed conditions; A calculation module, which calculates the wind speed-pitch angle curve; A second load reduction module, using the obtained wind speed-pitch angle curve to achieve pitch angle load reduction under high wind speed conditions; The control module realizes the joint primary frequency regulation control of the speed and pitch angle of the doubly-fed wind turbine based on the pitch angle load reduction.

[0057] In another embodiment of the present invention, a terminal device is provided, the terminal device includes a processor and a memory, the memory is used to store a computer program, the computer program includes program instructions, and the processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or other general-purpose processors, graphics processing units (GPU), tensor processing units (TPU), digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc., which are the computing core and control core of the terminal, which are suitable for implementing one or more instructions, and are specifically suitable for loading and executing one or more instructions to implement the corresponding method flow or corresponding functions; the processor described in the embodiment of the present invention can be used for the operation of the wind power primary frequency modulation method based on the combined load reduction of the rotation speed and the pitch angle, including: When the pitch angle is fixed, the suboptimal power tracking curve for speed load reduction is calculated; under medium and low wind speed conditions, the speed load reduction is achieved using the obtained optimal power tracking curve for speed load reduction; the wind speed-pitch angle curve is calculated; under high wind speed conditions, the pitch angle load reduction is achieved using the obtained wind speed-pitch angle curve; based on the pitch angle load reduction, the speed and pitch angle of the doubly fed wind turbine are controlled jointly with primary frequency regulation.

[0058] See also Figure 8 , the terminal device is a computer device, and the computer device 60 of this embodiment includes: a processor 61, a memory 62, and a computer program 63 stored in the memory 62 and executable on the processor 61. When the computer program 63 is executed by the processor 61, the wind power primary frequency regulation method based on the combined load reduction of the rotation speed and the pitch angle in the embodiment is implemented. To avoid repetition, it is not described one by one here. Alternatively, when the computer program 63 is executed by the processor 61, the functions of each model / unit in the wind power primary frequency regulation system based on the combined load reduction of the rotation speed and the pitch angle in the embodiment are implemented. To avoid repetition, it is not described one by one here.

[0059] The computer device 60 may be a computing device such as a desktop computer, a notebook, a PDA, or a cloud server. The computer device 60 may include, but is not limited to, a processor 61 and a memory 62. Those skilled in the art will appreciate that Figure 8This is only an example of the computer device 60 and does not constitute a limitation of the computer device 60. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the computer device may also include input and output devices, network access devices, buses, etc.

[0060] The processor 61 may be a central processing unit (CPU), or other general-purpose processors, graphics processing units (GPU), tensor processing units (TPU), digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc.

[0061] The memory 62 may be an internal storage unit of the computer device 60, such as a hard disk or memory of the computer device 60. The memory 62 may also be an external storage device of the computer device 60, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc., equipped on the computer device 60.

[0062] Furthermore, the memory 62 may include both an internal storage unit of the computer device 60 and an external storage device. The memory 62 is used to store computer programs and other programs and data required by the computer device. The memory 62 may also be used to temporarily store data that has been output or is to be output.

[0063] See also Figure 9 The terminal device 600 is an electronic device, and the electronic device is in the form of a general computing device. The components of the electronic device may include but are not limited to: at least one processing unit 610, at least one storage unit 620, a bus 630 connecting different platform components (including the storage unit 620 and the processing unit 610), a display unit 640, etc.

[0064] The storage unit stores program codes, which can be executed by the processing unit 610, so that the processing unit 610 performs the steps according to various exemplary embodiments of the present invention described in the above method section of this specification. For example, the processing unit 610 can perform the following steps: Figure 1 Follow the steps shown in .

[0065] The storage unit 620 may include a readable medium in the form of a volatile storage unit, such as a random access memory unit (RAM) 6201 and / or a cache memory unit 6202 , and may further include a read-only memory unit (ROM) 6203 .

[0066] The storage unit 620 may also include a program / utility 6204 having a set (at least one) of program modules 6205, such program modules 6205 including but not limited to: an operating system, one or more application programs, other program modules, and program data, each of which or some combination may include an implementation of a network environment.

[0067] Bus 630 may represent one or more of several types of bus structures, including a memory unit bus or memory unit controller, a peripheral bus, an accelerated graphics port, a processing unit, or a local bus using any of a variety of bus architectures.

[0068] The electronic device 600 may also communicate with one or more external devices 700 (e.g., keyboards, pointing devices, Bluetooth devices, etc.), may also communicate with one or more devices that enable a user to interact with the electronic device 600, and / or communicate with any device that enables the electronic device 600 to communicate with one or more other computing devices (e.g., routers, modems, etc.). Such communication may be performed via an input / output (I / O) interface 650. Furthermore, the electronic device 600 may also communicate with one or more networks (e.g., a local area network (LAN), a wide area network (WAN), and / or a public network, such as the Internet) via a network adapter 660. The network adapter 660 may communicate with other modules of the electronic device 600 via a bus 630. It should be understood that, although not shown in the figure, other hardware and / or software modules may be used in conjunction with the electronic device 600, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage platforms, etc.

[0069] In another embodiment of the present invention, the present invention also provides a storage medium, specifically a computer-readable storage medium, which is a memory device in a terminal device for storing programs and data. It can be understood that the computer-readable storage medium here can include both the built-in storage medium in the terminal device and the extended storage medium supported by the terminal device. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space, and these instructions can be one or more computer programs. It should be noted that the computer-readable storage medium here can be a high-speed RAM memory, or a non-volatile memory (Non-VolatileMemory), such as at least one disk memory.

[0070] The processor may load and execute one or more instructions stored in a computer-readable storage medium to implement the corresponding steps of the wind power primary frequency regulation method based on the combined load reduction of rotation speed and pitch angle in the above embodiment; the processor may load and execute the following steps of one or more instructions in the computer-readable storage medium: When the pitch angle is fixed, the suboptimal power tracking curve for speed load reduction is calculated; under medium and low wind speed conditions, the speed load reduction is achieved using the obtained optimal power tracking curve for speed load reduction; the wind speed-pitch angle curve is calculated; under high wind speed conditions, the pitch angle load reduction is achieved using the obtained wind speed-pitch angle curve; based on the pitch angle load reduction, the speed and pitch angle of the doubly fed wind turbine are controlled jointly with primary frequency regulation.

[0071] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can usually be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0072] To verify the effectiveness of the present invention, a simulation was built in MATLAB / Simulink. Figure 4 The model of the combined primary frequency regulation system of the thermal power unit and the fan is shown. In this simulation model, the system frequency is 60Hz. The parameters of each part in the simulation are as follows: The capacity of both steam turbine units is 900MW and the voltage level is 20kV; Transformers 2, 3, and 4 all have a capacity of 900MVA, with a low-voltage side voltage level of 20kV and a high-voltage side voltage level of 230kV; Transformer 1 has a capacity of 1.75MVA, a low-voltage side voltage level of 575V, and a high-voltage side voltage level of 20kV; The capacity of the doubly-fed induction wind turbine generator is 1.67MW and the voltage level is 575V.

[0073] In this simulation, the constant load is active load 1278MW, inductive reactive load 75MVar, and capacitive reactive load -387MVar; In load 1, the active load is 125MW and the reactive load is 30 MVar; The active load of load 2 is 100MW and the reactive load is 25 MVar.

[0074] When the simulation runs to 10s, load 1 is cut off; After running for 50s, load 2 is put into operation; This simulates the operating condition where load switching causes system frequency fluctuations.

[0075] According to the parameter calculation results, three wind speeds, low wind speed (8.7m / s), medium wind speed (11m / s), and high wind speed (14m / s), were selected in the simulation to test the working effect of the speed and pitch angle combined load reduction frequency modulation method in the present invention. The simulation results were compared with the case of no fan frequency modulation and only fan speed frequency modulation. Figure 5 , Figure 6 , Figure 7 Results shown.

[0076] See also Figure 5 , under the condition of low wind speed and no fan frequency modulation, only two synchronous generators perform frequency modulation once. At this time, whether load is added or removed, it will cause large frequency fluctuations. Since the pitch angle load reduction does not work at this time, the case of only fan speed frequency modulation and the case of speed and pitch angle combined load reduction frequency modulation are similar, and the frequency fluctuation caused by load cutting is significantly reduced. Due to the pitch angle frequency modulation, the combined load reduction frequency modulation has a faster response speed and can reach stability faster.

[0077] See also Figure 6 Under medium wind speed conditions, when the simulation runs to 10s load shedding, only the curve of fan speed frequency modulation coincides with the curve without fan frequency modulation, and no action is taken. The combined load shedding frequency modulation has a good primary frequency modulation effect. When the simulation runs to 50s load input, both fan speed frequency modulation and combined load shedding frequency modulation can be adjusted once. The frequency fluctuation and response speed of combined load shedding frequency modulation are significantly better than those of fan speed frequency modulation.

[0078] See also Figure 7 Under high wind speed conditions, the frequency change curves of fan speed frequency modulation and no fan primary frequency modulation during load shedding are basically the same, and the fan speed frequency modulation loses its primary frequency modulation function, while the combined load shedding frequency modulation can still perform primary frequency modulation through the pitch angle load shedding frequency modulation. The frequency fluctuation is slightly larger than that at medium and low wind speeds, and the response speed is faster.

[0079] In summary, the present invention is a method and system for wind power primary frequency regulation based on combined load reduction of rotation speed and pitch angle, which combines rotation speed load reduction and pitch angle load reduction to form a new suboptimal combined load reduction method, giving full play to the advantages of the two load reduction and frequency regulation methods, and overcoming the problems that rotation speed load reduction cannot be used in high wind speed ranges, and that pitch angle load reduction has a slow response speed and requires frequent actions. Speed ​​load reduction is used in medium and low wind speed ranges, and pitch angle load reduction is used in high wind speed ranges, ensuring that the doubly fed wind turbine has a certain amount of spare capacity for primary frequency regulation under various wind speed conditions.

[0080] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0081] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0082] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed in the present invention can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0083] In the embodiments provided by the present invention, it should be understood that the disclosed devices / terminals and methods can be implemented in other ways. For example, the device / terminal embodiments described above are only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0084] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0085] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0086] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium, etc. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0087] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices, and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of the processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure one A process or multiple processes and / or boxes Figure one A device that provides the functions specified in a block or multiple blocks.

[0088] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure one A process or multiple processes and / or boxes Figure one A function specified in one or more boxes.

[0089] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure one A process or multiple processes and / or boxes Figure one The steps for the functions specified in one or more boxes.

[0090] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A wind power primary frequency regulation method based on combined load shedding of rotation speed and pitch angle, characterized in that: The following steps are involved: S1. Calculate the speed reduction suboptimal power tracking curve at a fixed pitch angle; S2. Under low to medium wind speed conditions, speed reduction is achieved using the speed reduction optimal power tracking curve obtained in step S1; S3, calculating the wind speed-pitch angle curve; S4, using the wind speed-pitch angle curve obtained in step S3 to achieve pitch angle load reduction under high wind speed conditions; S5. Based on the pitch angle load reduction in step S4, the rotation speed and pitch angle of the doubly-fed wind turbine are controlled in conjunction with primary frequency regulation.

2. The wind power primary frequency modulation method based on combined load reduction of rotation speed and pitch angle according to claim 1 is characterized in that: Step S1 is specifically as follows: Calculate the wind speed range within which the wind turbine can operate and the pitch angle θ When the value is 0, different wind speeds V w The fan absorbed power P changes with the fan speed ω r Changing curves to get different wind speeds V w The maximum absorbed power of the fan is obtained, and then the maximum power tracking curve under the rated power of the fan is obtained. ω r -Max_P, and the wind speed when the wind turbine absorbs rated power when the pitch angle is 0 and the speed is at the maximum value V w_MaxP ; According to the maximum power tracking curve under the rated power of the fan ω r -Max_P calculates the load reduction power Del_P corresponding to different wind speeds when the load reduction rate is d%, and obtains the rotor speed upper limit Max ω r The following load shedding power curve ω r -Del_P( ω r ); According to the load shedding power curve ω r -Del_P( ω r ), calculate the fan absorbed power Del_P_Max when the rotor speed reaches the upper limit ω r , and the wind speed at this time V w_Delωr , the maximum wind speed and wind turbine absorbed power that can meet the load reduction rate of d% by speed reduction are obtained, and this is used as the threshold for switching the pitch angle to reduce load. According to the load reduction power curve ω r -Del_P( ω r ) and fitted the speed reduction suboptimal power tracking curve Del_P- ω r (P).

3. The wind power primary frequency regulation method based on combined load reduction of rotation speed and pitch angle according to claim 1 is characterized in that: In step S2, the speed reduction suboptimal power tracking curve Del_P- ω r (P), set speed suboptimal power reduction; When the total active power P output by the double-fed wind turbine is detected out Less than the threshold Del_P_Max ω r When the speed is reduced, the active power reserve is provided for the primary frequency regulation; When the total active power P output by the double-fed wind turbine is detected out Greater than Del_P_Max ω r When , the speed load reduction switches to pitch angle load reduction.

4. The method for primary frequency regulation of wind power based on combined load reduction of rotation speed and pitch angle according to claim 3 is characterized in that: When the total active power P output by the double-fed wind turbine is detected out Less than the threshold Del_P_Max ω r When the rotor speed command value is ω r_ref =Del_P- ω r (P out );When the total active power P output by the doubly fed wind turbine is detected out Greater than Del_P_Max ω r When the rotor speed command value is ω r_ref =Max ω r .

5. The wind power primary frequency regulation method based on combined load reduction of rotation speed and pitch angle according to claim 1, characterized in that: Step S3 is specifically as follows: According to the corresponding curve of wind speed and load reduction power V w -P( V w ) and the corresponding curve of pitch angle and power θ -P( θ ), the wind speed is [ V w_Delωr , V w_MaxP ] interval, the corresponding curve of wind speed and pitch angle V w -θ 1( V w ); When the wind speed is [ V w_MaxP , V w_ max ]hour, V w_ max To cut out the wind speed, the absorbed power of the double-fed wind turbine after load reduction reaches 1-d% times the rated value. V w -P( V w ) curve and θ -P( θ ) curve to calculate the wind speed and pitch angle corresponding curve V w –θ 2( V w ).

6. The method for primary frequency regulation of wind power based on combined load reduction of rotation speed and pitch angle according to claim 5, characterized in that: Calculate the rotor constant maximum speed, the wind speed is [ V w_Delωr , V w_MaxP ] interval, the wind turbine absorbs power and follows the load reduction power, and the corresponding curve of pitch angle and power is θ -P( θ ); According to the maximum power tracking curve under the rated power of the fan ω r -Max_P, calculated load reduction rate d%, wind speed is [ V w_Delωr , V w_MaxP ] interval, the corresponding curve of wind speed and load reduction power V w -P( V w ).

7. The method for primary frequency regulation of wind power based on combined load reduction of rotation speed and pitch angle according to claim 1, characterized in that: In step S4, according to the two wind speed-pitch angle curves obtained in step S3, V w_MaxP The pitch angle is set as the threshold for suboptimal power reduction. When the wind speed is detected to be [ V w_Delωr , V w_MaxP ] interval, according to the curve V w -θ 1( V w ),make θ=θ 1( V w ), as the pitch angle command value θ ref part of the pitch angle command value. θ ref middle; When the wind speed is [ V w_MaxP , V w_ max ] interval, let θ=θ 2( V w ) is accumulated to the pitch angle command value θ ref .

8. The method for primary frequency regulation of wind power based on combined load reduction of rotation speed and pitch angle according to claim 1, characterized in that: Step S5 is specifically as follows: Detect the frequency deviation of adjacent thermal power units ω , as the controlled variable of speed frequency modulation and pitch angle frequency modulation, after passing through the low-pass filter and dead zone limit, it is multiplied by the negative droop coefficient K ω r Add to the torque command value T of the double-fed fan e_ref middle; Set the pitch angle droop control coefficient K to a positive value θ , the speed deviation after dead zone and filtering d ω Multiply by K θ Then add it to the pitch angle command value of the doubly fed wind turbine θ ref middle; Take the speed closed-loop control and use PI adjustment to reduce the speed reference value ω r_ref Used to control the rotor speed. The PI link output is added to the speed frequency modulation result to generate the reference value T of the electromagnetic torque control loop. e_ref , used for rotor side current control; Generates pitch angle control angle signal for wind turbine control.

9. The method for primary frequency regulation of wind power based on combined load reduction of rotation speed and pitch angle according to claim 8, characterized in that: The angle signal of pitch angle control includes pitch control, pitch compensation, pitch angle frequency modulation and pitch angle compensation.

10. A wind power primary frequency regulation system based on combined load shedding of rotation speed and pitch angle, characterized in that: include: Curve module, which calculates the speed-reduced suboptimal power tracking curve at a fixed pitch angle; The first load shedding module uses the speed shedding optimal power tracking curve to achieve speed shedding under medium and low wind speed conditions; A calculation module, for calculating a wind speed-pitch angle curve; A second load reduction module, using the obtained wind speed-pitch angle curve to achieve pitch angle load reduction under high wind speed conditions; The control module realizes the joint primary frequency regulation control of the speed and pitch angle of the doubly-fed wind turbine based on the pitch angle load reduction.

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