Wind power primary frequency modulation method and system based on joint load reduction of rotational speed and pitch angle

Abstract

The application discloses a wind power primary frequency modulation method and system based on joint load reduction of rotating speed and pitch angle, and calculates a rotating speed load reduction suboptimal power tracking curve when the pitch angle is fixed; the obtained rotating speed load reduction suboptimal power tracking curve is used to realize rotating speed load reduction under the condition of medium and low wind speed; a wind speed-pitch angle curve is calculated; the obtained wind speed-pitch angle curve is used to realize pitch angle load reduction under the condition of high wind speed; and the primary frequency modulation control of the rotating speed and the pitch angle of a double-fed wind turbine is realized based on the pitch angle load reduction. The application fully gives play to the advantage intervals of the two load reduction frequency modulation modes, overcomes the problem that the rotating speed load reduction cannot be used in the high wind speed interval and the problem that the pitch angle load reduction has slow response speed and needs frequent action.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of primary frequency modulation of new energy power system, and particularly relates to a wind power primary frequency modulation method and system based on joint load shedding of rotational speed and pitch angle. BACKGROUND

[0002] Under the background of weak power grid in the northwest region, the frequency problems caused by a large number of new energy access are increasingly prominent. The high proportion of new energy access to the sending end of the weak power grid, large-scale DC project delivery, new energy fluctuation, DC fault and other problems impact the frequency of the power grid, resulting in a serious shortage of peak and frequency modulation capacity. At the same time, due to the lack of large conventional units and low short-circuit ratio, the weak power grid has weak synchronous support and poor frequency disturbance resistance, and has a high stability risk. Therefore, the participation of new energy stations in primary frequency modulation is an important way to solve the stability problems caused by high proportion of new energy, and is also an important trend at present. Compared with the primary frequency modulation mode of conventional units, the primary frequency modulation of new energy has the advantages of fast response speed, high precision, flexible control and low adjustment cost.

[0003] In order to ensure the safe and stable operation of the high proportion of wind power system, the primary frequency modulation capacity of the wind turbine is generally increased by adding a control link. This method needs to provide sufficient energy regulation source for the primary frequency modulation response of the wind turbine. The energy supply method usually has two ways of additional energy storage and load shedding standby. Additional energy storage mainly participates in system frequency response through energy storage batteries and super capacitors. Load shedding standby is a way to obtain a certain active power reserve by reducing the capture coefficient of wind energy through overspeed control and pitch control, so that the wind turbine operates at a suboptimal power tracking point. According to the principle, it can be divided into pitch angle load shedding and rotational speed load shedding. Pitch angle load shedding increases the pitch angle to leave active power reserve for primary frequency modulation; rotational speed load shedding increases the rotor speed when the wind turbine operates on the MPPT curve to make the operating point of the wind turbine deviate from the MPP, so as to leave standby capacity for primary frequency modulation.

[0004] However, the two ways of load shedding standby have their own applicable intervals. Rotational speed load shedding achieves the purpose of active power reserve through overspeed control. When the wind speed is large, rotational speed load shedding is harmful to the mechanical structure of the unit, so it is generally used at low wind speed. Pitch angle load shedding completes active power reserve through pitch control, which is suitable for a larger wind speed interval. However, since the pitch control involves a mechanical part, the response speed is slow, and if the action is too frequent, it can aggravate the wear and tear of the mechanical structure and reduce the service life of the wind turbine. Therefore, the two ways of load shedding standby have their own advantages and disadvantages, and it is difficult to achieve good primary frequency modulation effect by using them alone. SUMMARY

[0005] The technical problems to be solved by the present application are to provide a wind power primary frequency modulation method and system based on combined load reduction of rotational speed and pitch angle to solve the technical problems that the rotational speed load reduction or the pitch angle load reduction alone is difficult to be applied to both high and low wind speed ranges, and the doubly-fed wind turbine primary frequency modulation is only applicable to a small wind speed range.

[0006] The present application adopts the following technical solutions:

[0007] The wind power primary frequency modulation method based on combined load reduction of rotational speed and pitch angle comprises the following steps:

[0008] S1, calculating a suboptimal power tracking curve of rotational speed load reduction when the pitch angle is fixed;

[0009] S2, realizing rotational speed load reduction by using the optimal power tracking curve of rotational speed load reduction obtained in step S1 under the condition of medium and low wind speed;

[0010] S3, calculating a wind speed-pitch angle curve;

[0011] S4, realizing pitch angle load reduction by using the wind speed-pitch angle curve obtained in step S3 under the condition of high wind speed;

[0012] S5, realizing combined primary frequency modulation control of rotational speed and pitch angle of the doubly-fed wind turbine based on the pitch angle load reduction in step S4.

[0013] Preferably, step S1 is specifically:

[0014] calculating the pitch angle θ as a constant value 0 when the wind speed V w The wind turbine absorbs power P changes with the wind turbine rotational speed ω r The wind turbine absorbs power P changes with the wind turbine rotational speed V w The wind turbine absorbs power P changes with the wind turbine rotational speed ω r The wind turbine absorbs power P changes with the wind turbine rotational speed V w_MaxP ;

[0015] The wind turbine absorbs power P changes with the wind turbine rotational speed ω r The wind turbine absorbs power P changes with the wind turbine rotational speed ω r The wind turbine absorbs power P changes with the wind turbine rotational speed ω r The wind turbine absorbs power P changes with the wind turbine rotational speedω r );

[0016] According to the reduced power curve ω r -Del_P( ω r ), the maximum fan absorbed power Del_P_Max when the rotor speed reaches the upper limit is obtained ω r , and the wind speed at this time V w_Delωr , the maximum wind speed and the fan absorbed power that meet the d% reduction rate by speed reduction are obtained, and this is used as the threshold for switching the pitch angle reduction, according to the reduced power curve ω r -Del_P( ω r ), the suboptimal power tracking curve Del_P- ω r (P) is obtained by fitting the information of each point in

[0017] Preferably, in step S2, the suboptimal power tracking curve Del_P- ω r (P) obtained in step S1 is used to set the speed suboptimal power reduction;

[0018] When it is detected that the total active power P out output by the doubly-fed fan is less than the threshold Del_P_Max ω r , the speed reduction is used to provide active power reserve for primary frequency regulation;

[0019] When it is detected that the total active power P out output by the doubly-fed fan is greater than Del_P_Max ω r , the speed reduction is switched to the pitch angle reduction.

[0020] Preferably, when it is detected that the total active power P out output by the doubly-fed fan is less than the threshold Del_P_Max ω r , the rotor speed command value ω r_ref =Del_P- ω r (P out ); when it is detected that the total active power P out output by the doubly-fed fan is greater than Del_P_Max ω r , the rotor speed command value ω r_ref =Maxθ r .

[0021] Preferably, step S3 is specifically:

[0022] According to the wind speed and the load shedding power corresponding curve V w -P( V w ) and the pitch angle and the power corresponding curve θ -P( -θ ), when the wind speed is in the range of V w_Delωr , V w_MaxP , the wind speed and the pitch angle corresponding curve V w θ 1( V w );

[0023] When the wind speed is in the range of V w_MaxP , V w_ max , the wind speed and the pitch angle corresponding curve V w_ max is the cut-out wind speed, and the double-fed wind turbine absorbs power after load shedding reaches 1-d% times the rated value. According to the wind speed range V w -P( V w ) curve and θ -P( –θ ) curve, the wind speed and the pitch angle corresponding curve V w θ 2( V w ).

[0024] Preferably, when the wind speed is in the range of V w_Delωr , V w_MaxP , the wind turbine absorbs power following the load shedding power, and the pitch angle and the power corresponding curve θ -P( ω );

[0025] According to the maximum power tracking curve -θ r -Max_P of the wind turbine under the rated power, when the load shedding rate is d%, the wind speed is in the range of V w_Delωr , V w_MaxP , the wind speed and the load shedding power corresponding curve Vw -P( V w )。

[0026] Preferably, in step S4, according to the two segments of wind speed-pitch angle curve obtained in step S3, the pitch angle is set as V w_MaxP a threshold value of the pitch angle suboptimal power reduction, when the wind speed is detected in the interval of [V V w_Delωr , V w_MaxP ] interval, according to the curve V w θ= 1( V w ), let θ θ 1( V w ) as part of the pitch angle command value θ ref , added to the pitch angle command value θ=θ ref ;

[0027] When the wind speed is in the interval of [V V w_MaxP , V w_ max ], let θ 2( V w ) added to the pitch angle command value ω ref .

[0028] Preferably, step S5 is specifically:

[0029] Detect the frequency deviation d ω of the adjacent thermal power unit, as the controlled variable of the speed regulation and the pitch angle regulation, after low-pass filter and dead zone limit, multiplied by the negative droop coefficient K ω r added to the torque command value T e_ref of the doubly-fed wind turbine;

[0030] Set a positive pitch angle droop control coefficient K θ , after the speed deviation d θ is filtered and dead-zoned, multiplied by K θ added to the pitch angle command value ω ref of the doubly-fed wind turbine;

[0031] Take speed closed-loop control, in the form of PI regulation, the speed reference value Figure 1 r_refFor controlling the rotor speed, the PI link output is added to the result of the speed frequency modulation to generate a reference value T of the electromagnetic torque control loop e_ref For rotor side current control

[0032] An angle signal of the pitch angle control is generated for the wind turbine control.

[0033] Preferably, the angle signal of the pitch angle control comprises a pitch control, a pitch compensation, a pitch frequency modulation and a pitch compensation.

[0034] In a second aspect, an embodiment of the present application provides a wind power primary frequency regulation system based on combined speed and pitch angle load shedding, comprising:

[0035] A curve module is configured to calculate a speed load shedding suboptimal power tracking curve when the pitch angle is fixed.

[0036] A first load shedding module is configured to realize speed load shedding by using the speed load shedding optimal power tracking curve under the condition of medium and low wind speed.

[0037] A calculation module is configured to calculate a wind speed-pitch angle curve.

[0038] A second load shedding module is configured to realize pitch angle load shedding by using the wind speed-pitch angle curve under the condition of high wind speed.

[0039] A control module is configured to realize combined speed and pitch angle primary frequency regulation control of the doubly-fed wind turbine based on the pitch angle load shedding.

[0040] 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, and the processor realizes the steps of the wind power primary frequency regulation method based on combined speed and pitch angle load shedding when executing the computer program.

[0041] In a fourth aspect, an embodiment of the present application provides a computer readable storage medium comprising a computer program, and the computer program realizes the steps of the wind power primary frequency regulation method based on combined speed and pitch angle load shedding when executed by a processor.

[0042] In a fifth aspect, a chip comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor realizes the steps of the wind power primary frequency regulation method based on combined speed and pitch angle load shedding when executing the computer program.

[0043] In a sixth aspect, an embodiment of the present application provides an electronic device comprising a computer program, and the computer program realizes the steps of the wind power primary frequency regulation method based on combined speed and pitch angle load shedding when executed by the electronic device.

[0044] Compared with the prior art, the present application has at least the following beneficial effects:

[0045] The wind power primary frequency modulation method based on the joint load reduction of rotation speed and pitch angle combines rotation speed load reduction and pitch angle load reduction, adopts rotation speed load reduction in a medium-low wind speed range, adopts pitch angle load reduction in a high wind speed range, ensures that the doubly-fed wind turbine has certain spare capacity for primary frequency modulation under various wind speed conditions, and realizes good primary frequency modulation effect through cooperation of rotation speed frequency modulation and pitch angle frequency modulation.

[0046] Further, under the condition of medium-low wind speed, a suboptimal power tracking curve is calculated according to a maximum power tracking curve, thereby providing a basis for subsequent rotation speed load reduction.

[0047] Further, under the condition of medium-low wind speed, rotation speed load reduction is adopted to provide primary frequency modulation spare capacity, without changing the pitch angle, thereby reducing the number of actions of the pitch control system; rotation speed frequency modulation is adopted to perform primary frequency modulation, thereby fast response speed.

[0048] Further, under the condition of high wind speed, a pitch angle suboptimal power load reduction curve is calculated according to a pitch angle-power corresponding curve under the condition of constant maximum rotation speed of the rotor, thereby providing a basis for subsequent pitch angle load reduction.

[0049] Further, under the condition of high wind speed, pitch angle frequency modulation is adopted to provide primary frequency modulation spare capacity, when the rotation speed reaches the maximum and sufficient spare capacity cannot be provided, the pitch angle frequency modulation is used to make up the spare capacity, and when the wind speed reaches a certain level and the rotation speed load reduction cannot provide spare capacity, the pitch angle load reduction is completely used to provide sufficient spare capacity, thereby significantly expanding the wind speed range of the doubly-fed wind turbine participating in primary frequency modulation.

[0050] Further, on the basis of sufficient primary frequency modulation spare capacity obtained through joint load reduction of rotation speed and pitch angle, rotation speed frequency modulation and pitch angle frequency modulation cooperate with each other, thereby realizing good primary frequency modulation effect.

[0051] It can be understood that the beneficial effects of the above-mentioned second aspect to sixth aspect can be referred to the related description in the first aspect, which will not be repeated here.

[0052] In summary, the present application combines rotation speed load reduction and pitch angle load reduction, forms a new suboptimal joint load reduction method, fully utilizes the advantage intervals of the two load reduction frequency modulation methods, overcomes the problems that rotation speed load reduction cannot be used in a high wind speed range and pitch angle load reduction has slow response speed and needs frequent action. Rotation speed load reduction is adopted in a medium-low wind speed range, pitch angle load reduction is adopted in a high wind speed range, and the doubly-fed wind turbine has certain spare capacity for primary frequency modulation under various wind speed conditions.

[0053] The technical solutions of the present application will be further described in detail below with the aid of the accompanying drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0054] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be briefly introduced as follows. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0055] Figure 2 Flow chart for primary frequency modulation of combined speed and pitch angle load reduction;

[0056] Figure 3 Control block diagram for speed;

[0057] Figure 4 Control block diagram for pitch angle;

[0058] Figure 5 System diagram of combined primary frequency modulation of thermal power unit and fan;

[0059] Figure 6 Comparison diagram of frequency modulation effect of combined speed and pitch angle load reduction at low wind speed;

[0060] Figure 7 Comparison diagram of frequency modulation effect of combined speed and pitch angle load reduction at medium wind speed;

[0061] Figure 8 Comparison diagram of frequency modulation effect of combined speed and pitch angle load reduction at high wind speed;

[0062] Figure 9 Schematic diagram of a computer device provided by an embodiment of the present application;

[0063] Figure 1 Block diagram of a chip provided by an embodiment of the present application. DETAILED DESCRIPTION

[0064] The technical solutions in the embodiments of the present application will be described clearly and completely below with the aid of the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort belong to the scope of protection of the present application.

[0065] In the description of the present application, it should be understood that the terms "include" and "contain" indicate the existence of described features, whole, steps, operations, elements and / or components, but do not exclude the existence or addition of one or more other features, whole, steps, operations, elements, components and / or sets thereof.

[0066] It should also be understood that the terms used in the specification of the present application are for the purpose of describing particular embodiments only and are not intended to be limiting of the present application. As used in the specification and appended claims of the present application, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0067] It should further be understood that the term "and / or" as used in the specification of the present application and appended claims is to be interpreted as including any combination of one or more of the associated listed items as well as all possible combinations of the items, and includes the combinations of the items, for example, A and / or B can mean A alone, A and B together, or B alone. In addition, the character " / " in the present application generally represents an "or" relationship between the objects before and after the " / ".

[0068] It should be understood that, although the terms first, second, third, etc. can be used in the embodiments of the present application to describe a certain range, etc., these ranges should not be limited to these terms. These terms are only used to distinguish the ranges from each other. For example, the first range can also be referred to as the second range, and similarly, the second range can also be referred to as the first range, without departing from the scope of the embodiments of the present application.

[0069] Depending on the context, the word "if" as used herein can be interpreted to mean "when" or "while" or "in response to determining" or "in response to detecting." Similarly, the phrase "if it is determined" or "if [a stated condition or event] is detected" can be interpreted to mean "upon determining" or "in response to determining" or "upon detecting [the stated condition or event]" or "in response to detecting [the stated condition or event]."

[0070] Various structural schematic diagrams according to the disclosed embodiments of the present application are shown in the accompanying drawings. These diagrams are not drawn to scale, in which certain details are exaggerated for clarity of presentation and precision, and certain details can be omitted. The shapes of various regions, layers, and the relative size and position relationship between them shown in the diagrams are only exemplary, and in actuality, there can be deviations due to manufacturing tolerances or technical limitations, and a person skilled in the art can additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0071] The application provides a wind power primary frequency modulation method based on combined speed and pitch angle load shedding, which combines speed load shedding and pitch angle load shedding to form a new suboptimal combined load shedding method, fully utilizes the advantage intervals of the two load shedding frequency modulation modes, overcomes the problems that speed load shedding cannot be used in high wind speed intervals and pitch angle load shedding has slow response speed and needs frequent action; the speed load shedding is used in the medium and low wind speed intervals, and the pitch angle load shedding is used in the high wind speed intervals, so that the doubly-fed wind turbine has certain spare capacity for primary frequency modulation under various wind speed conditions.

[0072] Please refer to θ , the application is a wind power primary frequency modulation method based on combined speed and pitch angle load shedding, which comprises the following steps:

[0073] S1, calculating a speed load shedding suboptimal power tracking curve when the pitch angle is fixed;

[0074] According to the wind speed range in which the wind turbine can work, the wind turbine absorption power formula is used to calculate the fixed pitch angle (pitch angle ω =0) in the range, different wind speeds V w The curve of the wind turbine absorption power P changes with the wind turbine speed ω r , and the maximum wind turbine absorption power and the corresponding pitch angle under different wind speeds V w are obtained according to the curves, so as to obtain a maximum power tracking (MPPT) curve ω r -Max_P of the wind turbine rated power, and the wind speed V w_MaxP when the wind turbine absorbs the rated power under the condition that the pitch angle is 0 and the speed is the maximum.

[0075] According to the MPPT curve, the load shedding power Del_P corresponding to different wind speeds when the load shedding rate is d% is calculated, and the upper limit Max ω r of the rotor speed is obtained. ω r The following load shedding power curve ω r -Del_P(

[0076] According to the load shedding power curve, the wind turbine absorption power Del_P_Max ω r when the rotor speed reaches the upper limit is obtained, and the wind speed V w_Delωr at this time, that is, the maximum wind speed and the wind turbine absorption power that can be met by only speed load shedding, is taken as the threshold for switching the pitch angle load shedding, and the load shedding power curve ωr -Del_P( ω r ) of each point in Del_P ω r (P) is obtained by quadratic function fitting.

[0077] S2, under the condition of medium-low wind speed, the speed reduction optimal power tracking curve obtained in step S1 is used to realize speed reduction;

[0078] Medium-low wind speed refers to the interval of wind speed greater than the cut-in wind speed of the doubly-fed wind turbine and less than the wind speed calculated in step S1. V w_MaxP .

[0079] The suboptimal power tracking curve Del_P ω r (P) obtained according to the above steps is used to set the speed suboptimal power reduction, and when the total active power P out output by the doubly-fed wind turbine is less than the threshold Del_P_Max ω r , active power reserve for primary frequency regulation is provided by using speed reduction, and the rotor speed instruction value ω r_ref =Del_P ω r (P out ), when P out is greater than Del_P_Max ω r , the speed reduction is switched to pitch angle reduction, and at this time, the rotor speed instruction value is a certain value, i.e. ω r_ref =Max θ r .

[0080] S3, the wind speed-pitch angle curve is calculated;

[0081] According to the wind turbine absorbed power formula , when the wind speed is in the interval of [ V w_Delωr , V w_MaxP ], the pitch angle-power corresponding curve θ -P( ω ) is calculated under the condition that the wind turbine absorbed power follows the reduced power.

[0082] According to the MPPT curve θ r -Max_P, when the reduced rate is d%, the wind speed is in the interval of [ V w_Delωr ,V w_MaxP During the specified interval, the curves corresponding to wind speed and load reduction power are shown. V w -P( V w ).

[0083] Based on the curve corresponding to wind speed and load reduction power V w -P( V w (and the curves corresponding to pitch angle and power) θ - P( Vw - θ ), from which the wind speed is at [ V w_Delωr , V w_MaxP During the specified interval, the curves corresponding to wind speed and propeller pitch angle are shown. θ 1( V w When the wind speed is at [ V w_MaxP , V w_ max ]hour( V w_ max To cut off the wind speed (fans above this speed are shut down to protect them), the reduced load on the doubly-fed fan allows it to absorb 1-d% of its rated power. Similarly, the power absorption of the fan within this wind speed range can be adjusted accordingly. V w -P( V w ) curve and θ - P( – θ The curves corresponding to wind speed and blade pitch angle are calculated. V w -θ 2( V w ).

[0084] S4. Under high wind speed conditions, use the wind speed-pitch angle curve obtained in step S3 to achieve pitch angle load reduction.

[0085] High wind speed refers to wind speed greater than the wind speed calculated in step S1. V w_MaxP Less than the cut-off velocity of the doubly fed fan V w_ max The range.

[0086] Based on the two wind speed-pitch angle curves obtained from the above steps, V w_MaxP Set a suboptimal power load reduction for the pitch angle to the threshold, when the detected wind speed is at [ V w_Delωr , V w_MaxPWhen the wind speed is in the interval [V V w θ=θ 1( V w ), let θ 1( V w ) be added to the pitch angle command value θ ref as part of the pitch angle command value θ=θ ref . Similarly, when the wind speed is in the interval [V V w_MaxP , V w_ max ], let θ 2( V w ) be added to the pitch angle command value ω ref .

[0087] S5, based on the pitch angle reduction obtained in step S4, implement the speed and pitch angle combined primary frequency modulation control of the doubly-fed wind turbine.

[0088] S501, speed frequency modulation

[0089] First, detect the frequency deviation d ω of the adjacent thermal power unit, as the controlled variable of the speed frequency modulation and the pitch angle frequency modulation, after low-pass filtering and dead zone limiting, multiply by the negative droop coefficient K ω r and add to the doubly-fed wind turbine torque command value T e_ref .

[0090] S502, pitch angle frequency modulation

[0091] Set the positive pitch angle droop control coefficient K θ , after the dead zone and filtering of the speed deviation d θ , multiply by K θ and add to the pitch angle command value of the doubly-fed wind turbine Figure 2 ref .

[0092] S503, speed control

[0093] Please refer to ω , the speed control adopts speed closed-loop control, using PI regulation, the speed reference value Figure 3 r_ref obtained by speed reduction is used to control the rotor speed, the PI link output is added to the result of the speed frequency modulation to generate the reference value T e_ref of the electromagnetic torque control loop, which is used for subsequent rotor-side current control.

[0094] S504, pitch angle control

[0095] Please refer to Figure 8 The pitch angle control is composed of four parts of pitch angle control, pitch angle compensation, pitch angle frequency modulation and pitch angle compensation, and the angle signals of the pitch angle control are generated by adding the outputs of the four parts for fan control.

[0096] Those skilled in the art can understand that various aspects of the present application can be implemented as a system, a method or a program product. Therefore, various aspects of the present application can be embodied in the form of a complete hardware implementation, a complete software implementation (including firmware, microcode, etc.), or an implementation of hardware and software aspects combined, which can be collectively referred to as "circuitry", "module" or "platform" here.

[0097] In another embodiment of the present application, a wind power primary frequency modulation system based on combined load reduction of rotational speed and pitch angle is provided, which can be used to implement the wind power primary frequency modulation method based on combined load reduction of rotational speed and pitch angle as described above. Specifically, the wind power primary frequency modulation 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.

[0098] The curve module calculates a rotational speed load reduction suboptimal power tracking curve when the pitch angle is fixed.

[0099] The first load reduction module realizes rotational speed load reduction by using the rotational speed load reduction optimal power tracking curve under medium and low wind speed conditions.

[0100] The calculation module calculates a wind speed-pitch angle curve.

[0101] The second load reduction module realizes pitch angle load reduction by using the obtained wind speed-pitch angle curve under high wind speed conditions.

[0102] The control module realizes combined primary frequency modulation control of the rotational speed and the pitch angle of the doubly-fed wind turbine based on the pitch angle load reduction.

[0103] In another embodiment of the present application, a terminal device is provided, which comprises a processor and a memory, the memory is configured to store a computer program, the computer program comprises program instructions, and the processor is configured to execute the program instructions stored in the computer storage medium. The processor can be a central processing unit (CPU), and can also be other general-purpose processors, graphics processing units (GPUs), tensor processing units (TPUs), digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs) 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, and are suitable for implementing one or more instructions, and are particularly suitable for loading and executing one or more instructions to implement a corresponding method flow or a corresponding function; the processor in the embodiments of the present application can be used for the operation of the wind power primary frequency modulation method based on the combined load reduction of the rotational speed and the pitch angle, comprising:

[0104] In the constant pitch angle, the rotational speed load reduction suboptimal power tracking curve is calculated; in the low wind speed condition, the obtained rotational speed load reduction optimal power tracking curve is used to realize the rotational speed load reduction; the wind speed-pitch angle curve is calculated; in the high wind speed condition, the obtained wind speed-pitch angle curve is used to realize the pitch angle load reduction; and the rotational speed and the pitch angle of the doubly-fed wind turbine are jointly controlled for the primary frequency modulation based on the pitch angle load reduction.

[0105] Please refer to Figure 8 The terminal device is a computer device, and the computer device 60 of the embodiment comprises a processor 61, a memory 62, and a computer program 63 stored in the memory 62 and executable on the processor 61, wherein the computer program 63 is executed by the processor 61 to implement the wind power primary frequency modulation method based on the combined load reduction of the rotational speed and the pitch angle in the embodiment. To avoid repetition, details are not described here. Alternatively, the computer program 63 is executed by the processor 61 to implement the functions of each model / unit in the wind power primary frequency modulation system based on the combined load reduction of the rotational speed and the pitch angle in the embodiment. To avoid repetition, details are not described here.

[0106] The computer device 60 can be a desktop computer, a notebook computer, a palm computer, a cloud server and the like. The computer device 60 can include, but is not limited to, a processor 61 and a memory 62. Those skilled in the art can understand that Figure 9The computer device 60 is merely an example and does not constitute a limitation on the computer device 60, which can include more or fewer components than shown, or combine some components, or have different components, such as the computer device can also include an input / output device, a network access device, a bus, etc.

[0107] The processor 61 can be a central processing unit (CPU), and can also be other general-purpose processors, graphics processing units (GPUs), tensor processing units (TPUs), digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs) or other programmable logic devices, discrete gates or transistor logic, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0108] The memory 62 can be an internal storage unit of the computer device 60, such as a hard disk or a memory of the computer device 60. The memory 62 can 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.

[0109] Further, the memory 62 can include both an internal storage unit and an external storage device of the computer device 60. The memory 62 is used to store computer programs and other programs and data required by the computer device. The memory 62 can also be used to temporarily store data that has been output or will be output.

[0110] Please refer to Figure 1 , the terminal device 600 is an electronic device, which is in the form of a general-purpose computing device. The components of the electronic device can 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.

[0111] 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 application described in the above method part of the present specification. For example, the processing unit 610 can perform the steps as shown in the above method part of the present specification. Figure 4

[0112] The storage unit 620 can include a readable medium in the form of a volatile storage unit, such as a random access memory (RAM) 6201 and / or a cache memory 6202, and can further include a read-only memory (ROM) 6203.

[0113] The storage unit 620 can further include a program / utility 6204 having a set of programs / modules 6205, including but not limited to: an operating system, one or more application programs, other program modules, and program data, each or a combination thereof, which can include implementation of a network environment.

[0114] The bus 630 can represent one or more of several types of bus structures, including a storage unit bus or bus controller, a peripheral bus, a graphics acceleration port, a processing unit bus, or a local bus using any of a variety of bus architectures.

[0115] The electronic device 600 can also communicate with one or more external devices 700 such as a keyboard or pointing device, a Bluetooth device, etc.; user interfaces and / or peripheral devices such as a printer, scanner, or the like; and / or one or more devices in a communications system. Communication with one or more devices can occur via an input / output (I / O) interface 650. Still yet, the electronic device 600 can communicate with one or more networks such as a local area network (LAN), a general wide area network (WAN), and / or a public network (e.g., the Internet) via a network adapter 660. As depicted, the network adapter 660 can communicate with the other components of the electronic device 600 via the bus 630. It should be appreciated that the network adapter 660 and / or the bus 630 can be implemented using one or more types of communication media, such as IO devices, I / O device adapters, wireless links, wires, cables, and the like, including bus communication to one or more other buses.

[0116] ​In still another embodiment of the present application, the present application also provides a storage medium, specifically a computer readable storage medium, which is a memory device in the terminal device, used for storing programs and data. It can be understood that the computer readable storage medium herein can include the built-in storage medium in the terminal device, and of course can also include the expansion storage medium supported by the terminal device. The computer readable storage medium provides a storage space, which stores the operating system of the terminal. Moreover, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space, and the instructions can be one or more computer programs. It should be noted that the computer readable storage medium herein can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory.

[0117] The one or more instructions stored in the computer readable storage medium can be loaded and executed by the processor to realize the corresponding steps of the wind power primary frequency modulation method based on the combined load reduction of the rotational speed and the pitch angle in the above-mentioned embodiments; the one or more instructions in the computer readable storage medium are loaded and executed by the processor as follows:

[0118] When the pitch angle is fixed, the suboptimal power tracking curve of the rotational speed load reduction is calculated; under the condition of medium and low wind speed, the obtained optimal power tracking curve of the rotational speed load reduction is used to realize the rotational speed load reduction; the wind speed-pitch angle curve is calculated; under the condition of high wind speed, the obtained wind speed-pitch angle curve is used to realize the pitch angle load reduction; and the combined primary frequency modulation control of the rotational speed and the pitch angle of the doubly-fed wind turbine is realized based on the pitch angle load reduction.

[0119] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application but not all the embodiments. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. All other embodiments obtained by a person of ordinary skill in the art without creative work on the basis of the embodiments in the present application belong to the scope of protection of the present application.

[0120] To verify the effectiveness of the present application, a model of the combined primary frequency modulation system of the thermal power unit and the wind turbine is built in MATLAB / Simulink as shown in FIG. 1. Figure 5

[0121] ​The capacity of the two steam turbine units is 900 MW, and the voltage level is 20 kV.

[0122] The capacity of the transformers 2, 3, 4 is 900 MVA, the voltage level of the low-voltage side is 20 kV, and the voltage level of the high-voltage side is 230 kV.

[0123] The capacity of the transformer 1 is 1.75 MVA, the voltage level of the low-voltage side is 575 V, and the voltage level of the high-voltage side is 20 kV.

[0124] The capacity of the doubly-fed induction wind generator is 1.67 MW, and the voltage level is 575 V.

[0125] In the simulation, the constant load is an active load of 1278 MW, an inductive reactive load of 75 MVar, and a capacitive reactive load of -387 MVar.

[0126] In the load 1, the active load is 125 MW, and the reactive load is 30 MVar.

[0127] In the load 2, the active load is 100 MW, and the reactive load is 25 MVar.

[0128] When the simulation runs to 10 s, the load 1 is cut off.

[0129] When the simulation runs to 50 s, the load 2 is put in.

[0130] In this way, the working condition of the load switching causing the system frequency fluctuation is simulated.

[0131] According to the parameter calculation result, in the simulation, three wind speeds, i.e., a low wind speed (8.7 m / s), a medium wind speed (11 m / s), and a high wind speed (14 m / s), are selected to test the working effect of the rotational speed and pitch angle combined load reduction frequency modulation method in the application. The simulation result is compared with the case of no wind generator frequency modulation and the case of only wind generator rotational speed frequency modulation, and the result is shown in Figure 6 、 Figure 7 、 Figure 5 .

[0132] Please refer to Figure 6 , under the condition of the low wind speed and no wind generator frequency modulation, only two synchronous generators perform frequency modulation once, at this time, whether the load is put in or cut off, it will cause a larger frequency fluctuation. Since the pitch angle load reduction does not act at this time, the case of only wind generator rotational speed frequency modulation is similar to the case of rotational speed and pitch angle combined load reduction frequency modulation, the frequency fluctuation caused by the load switching is obviously reduced. Since the pitch angle frequency modulation is provided, the combined load reduction frequency modulation has a faster response speed, and can reach the stability faster.

[0133] Please refer to Figure 7In the case of high wind speed, the frequency change curve of the fan speed frequency modulation and the primary frequency modulation without the fan coincides basically, the fan speed frequency modulation loses the primary frequency modulation effect, and the joint load reduction frequency modulation can still perform the primary frequency modulation through the pitch angle load reduction frequency modulation, the frequency fluctuation is slightly larger than that in the case of medium and low wind speed, and the response speed is relatively fast.

[0134] Please refer to Figure 1 In the case of high wind speed, the frequency change curve of the fan speed frequency modulation and the primary frequency modulation without the fan coincides basically, the fan speed frequency modulation loses the primary frequency modulation effect, and the joint load reduction frequency modulation can still perform the primary frequency modulation through the pitch angle load reduction frequency modulation, the frequency fluctuation is slightly larger than that in the case of medium and low wind speed, and the response speed is relatively fast.

[0135] In summary, the wind power primary frequency modulation method and system based on the joint load reduction of the speed and the pitch angle combine the speed load reduction and the pitch angle load reduction, form a new suboptimal joint load reduction method, give full play to the advantage interval of the two load reduction frequency modulation modes, overcome the problems that the speed load reduction cannot be used in the high wind speed interval, and the pitch angle load reduction has slow response speed and needs frequent action. The speed load reduction is adopted in the medium and low wind speed interval, and the pitch angle load reduction is adopted in the high wind speed interval, so that the doubly-fed fan has certain standby capacity for primary frequency modulation under various wind speed conditions.

[0136] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above functional units and modules is exemplified, and in actual application, the above functions can be completed by different functional units and modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or software. In addition, the specific names of the functional units and modules are only for mutual distinction, and do not limit the protection scope of the application. The specific working process of the units and modules in the system can refer to the corresponding process in the foregoing method embodiments, which will not be repeated here.

[0137] In the above embodiments, the description of each embodiment has its own emphasis, and the parts not described or recorded in a certain embodiment can be referred to the related description of other embodiments.

[0138] Those skilled in the art can understand that the units and algorithm steps of each example described in combination with the embodiments disclosed in the present application can be realized in electronic hardware or in combination of computer software and electronic hardware. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0139] In the embodiments provided by the present application, it should be understood that the disclosed apparatus / terminal and method can be implemented in other ways. For example, the apparatus / terminal embodiments described above are merely schematic. The division of the modules or units is merely a logical function division, and there can be another division manner in actual implementation. For example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed coupling or direct coupling or communication connection between the units can be indirect coupling or communication connection through some interface, device or unit, and can be electrical, mechanical or in other forms.

[0140] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, i.e. they can be located in one place, or distributed on a plurality of network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiments.

[0141] In addition, each functional unit in each embodiment of the present application can be integrated into a processing unit, or each unit can exist physically independently, or two or more units can be integrated into one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0142] The integrated module / unit, if realized in the form of a software function unit and sold or used as an independent product, can be stored in a computer-readable storage medium. Based on such understanding, all or part of the processes in the above-mentioned embodiment methods can also be completed by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of each method embodiment when executed by a processor. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or some intermediate forms, etc. The computer-readable medium can include any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc. It should be noted that the computer-readable medium can include or exclude contents according to the requirements of legislation and patent practice in the jurisdiction, for example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0143] The present application is described with reference to flowcharts and / or block diagrams of methods, devices, and computer program products according to embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of flows and / or blocks in the flowcharts and / or block diagrams 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 produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce a device that implements the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one or more flows and / or blocks Figure 1 The functions specified in one or more flows and / or blocks

[0144] These computer program instructions can also be stored in a computer-readable memory that can direct the computer or other programmable data processing device to work in a specific way, so that the instructions stored in the computer-readable memory produce a product including instruction devices that implement the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one or more flows and / or blocks Figure 1 The functions specified in one or more flows and / or blocks

[0145] These computer program instructions can also be loaded into a computer or other programmable data processing devices, so that a series of operational steps are performed on the computer or other programmable data processing devices to generate a computer implemented process, so that the instructions executed on the computer or other programmable data processing devices provide a process for implementing the functions specified in the flowchart Figure 1 one flow or multiple flows and / or the functions specified in the block ​ one flow or multiple flows and / or the functions specified in the block

[0146] The above is only to illustrate the technical idea of the present application, and cannot limit the protection scope of the present application. Any modification made according to the technical idea of the present application on the basis of the technical scheme falls within the protection scope of the claims of the present application.

Claims

1. A wind power primary frequency regulation method based on combined load reduction of rotational speed and pitch angle, characterized in that, The method comprises the following steps: S1, calculating a speed reduction suboptimal power tracking curve at a constant pitch angle; S2, implementing speed reduction under a medium-low wind speed condition by using the speed reduction suboptimal power tracking curve obtained in step S1; S3, calculating a wind speed-pitch angle curve, specifically: According to the wind speed and the corresponding curve of the load reduction power V w -P( V w ) and the corresponding curve of the pitch angle and the power θ -P( θ ), when the wind speed is in the interval of [ V w_Delωr , V w_MaxP ], the corresponding curve of the wind speed and the pitch angle V w -θ 1( V w ); When the wind speed is at [ V w_MaxP , V w_ max ]hour, V w_ max To cut off the wind speed, the power absorption of the doubly-fed fan after load reduction reaches 1-d% of its rated value, based on the wind speed range. V w -P( V w ) curve and θ -P( θ The curves corresponding to wind speed and blade pitch angle are calculated. V w –θ 2( V w ); The rotor constant maximum rotating speed is calculated, the wind speed is in the interval of [ V w_Delωr , V w_MaxP ], the fan absorbed power follows the load shedding power, the pitch angle and the power corresponding curve θ -P( θ ) ; According to the maximum power tracking curve under the rated power of the fan ω r - Max_P, the wind speed corresponding curve when the wind speed is in the interval of [d%, Max_P] V w_Delωr , V w_MaxP ] and the load reduction rate is d% V w - P( V w ) S4. Under high wind speed conditions, utilize the wind speed-pitch angle curve obtained in step S3 to achieve pitch angle reduction. Based on the two segments of the wind speed-pitch angle curve obtained in step S3, V w_MaxP Set a suboptimal power load reduction for the pitch angle to the threshold, when the detected wind speed is at [ V w_Delωr , V w_MaxP When the interval is reached, according to the curve V w -θ 1( V w ),make θ=θ 1( V w ), as the pitch angle command value θ ref A portion is added to the pitch angle command value. θ ref middle; When the wind speed is [ V w_MaxP , V w_ max When the interval is [0, let 0] θ=θ 2( V w Accumulate to the pitch angle command value θ ref ; S5, implementing combined primary frequency modulation control of the speed and the pitch angle of the doubly-fed wind turbine based on the pitch angle reduction of step S4, specifically: Detecting the frequency deviation adjacent to the thermal power unit, as the controlled variable of the speed frequency modulation and the pitch angle frequency modulation, after low-pass filter and dead zone limit, multiplying the negative value of droop coefficient K ω r Adding to the torque instruction value T of the double-fed fan e_ref Middle; A positive value is set to a pitch angle droop control coefficient K θ , the speed deviation after the dead zone and filtering is multiplied by K θ , and the result is added to a pitch angle command value of the doubly-fed wind power generator θ ref in the middle; The speed reference value obtained by reducing the speed under load is controlled in a closed loop with PI regulation ω r_ref For controlling the rotor speed, the output of the PI element is added to the result of the speed regulation to generate the reference value T of the electromagnetic torque control loop e_ref For rotor-side current control generating an angle signal of the pitch angle control for wind turbine control. 2.The wind power primary frequency modulation method based on the combined load reduction of rotational speed and pitch angle according to claim 1, characterized in that, Step S1 is specifically: The pitch angle is calculated within the working wind speed range of the wind turbine θ When the pitch angle is 0, the wind speed is different V w The power absorbed by the wind turbine under different wind speeds ω r The power absorbed by the wind turbine under different wind speeds V w The maximum power absorbed by the wind turbine, and then the maximum power tracking curve under the rated power of the wind turbine ω r The wind speed when the wind turbine absorbs the rated power under the condition that the pitch angle is 0 and the speed is 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 upper limit of the rotor speed Max ω r The following load reduction power curve ω r Del_P( ω r ); According to the reduced power curve ω r -Del_P( ω r ), the rotor speed reaches the upper limit of the fan absorbed power Del_P_Max ω r , and the wind speed at this time V w_Delωr , the maximum wind speed and the fan absorbed power that meet the d% reduction rate by reducing the speed are obtained, and this is used as the threshold for switching the pitch angle reduction, according to the reduced power curve ω r -Del_P( ω r ) of each point, the suboptimal power tracking curve Del_P- ω r (P) is obtained by fitting. 3.The wind power primary frequency modulation method based on the combined load reduction of rotation speed and pitch angle according to claim 1, characterized in that, In step S2, the speed suboptimal power unloading tracking curve Del_P is obtained according to the speed unloading tracking curve in step S1. ω r (P), the speed suboptimal power unloading is set. When the total active power P out is less than the threshold value Del_P_Max ω r , the speed reduction mode is adopted to provide active reserve for primary frequency regulation. When the total active power P out is detected to be greater than Del_P_Max ω r a pitch angle derating is switched to from the rotational speed derating.

4. The method of claim 3, wherein the method is based on combined load reduction of rotational speed and pitch angle. When the total active power P out out of the doubly-fed wind turbine is detected to be less than a threshold value Del_P_Max ω , the rotor speed command value ω ω* is made to be r = Del_P ω ; when the total active power P r_ref out of the doubly-fed wind turbine is detected to be greater than Del_P_Max ω , the rotor speed command value r ω* is made to be out = Max ω ; and when the total active power P out out of the doubly-fed wind turbine is detected to be equal to Del_P_Max ω , the rotor speed command value r ω* is made to be = Max The angle signal of the pitch angle control comprises pitch control, pitch compensation, pitch frequency modulation and pitch compensation. .

5. The method of claim 1, wherein the method is based on combined load reduction of rotational speed and pitch angle. The angle signal of the pitch angle control comprises pitch control, pitch compensation, pitch frequency modulation and pitch compensation.

6. A wind power primary frequency regulation system based on combined load reduction of rotational speed and pitch angle, characterized in that, The wind power primary frequency modulation method based on combined speed and pitch angle reduction according to claim 1 comprises: a curve module, which calculates a speed reduction suboptimal power tracking curve at a constant pitch angle; a first reduction module, which implements speed reduction by using the speed reduction optimal power tracking curve under a medium-low wind speed condition; a calculation module, which calculates a wind speed-pitch angle curve; a second reduction module, which implements pitch angle reduction by using the obtained wind speed-pitch angle curve under a high wind speed condition; a control module, which implements combined primary frequency modulation control of the speed and the pitch angle of the doubly-fed wind turbine based on the pitch angle reduction.

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