Primary frequency modulation control method, system and medium for double-fed wind turbine

Abstract

The invention discloses a primary frequency modulation control method, system and medium of a doubly-fed wind turbine, belonging to the field of wind power generation, and the method comprises: based on the mapping relationship between wind turbine power, pitch angle, wind turbine speed and wind speed, calculating the equivalent wind speed to further calculate the pitch angle compensation signal; calculating the pitch angle reference signal to control the pitch angle of the wind turbine according to the pitch angle compensation signal, wind turbine power and wind turbine speed, and calculating the electromagnetic torque reference signal; calculating the first drive signal to drive the rotor side PWM converter according to the electromagnetic power, output reactive power, three-phase voltage and electromagnetic torque reference signal of the wind turbine; calculating the second drive signal to drive the grid side PWM converter according to the collected wind turbine DC bus capacitor voltage and grid side q-axis current. In the case of inaccurate wind speed measurement, the maximum wind turbine power that should be obtained at the current wind speed can be accurately predicted, and on this basis, the wind turbine can be precisely adjusted to reduce the load.

Description

Technical Field

[0001] The present invention belongs to the field of wind power generation, and more specifically, relates to a primary frequency modulation control method, system and medium for a doubly-fed wind turbine. Background Art

[0002] Doubly Fed Induction Generator (DFIG) is the most widely used wind turbine. When the frequency of the grid-connected power system is lower than the rated frequency, the new energy station should increase the active output according to the primary frequency modulation curve, and the primary frequency modulation power change limit setting should be no less than 6% of the operating power. According to the above standards, if new energy equipment such as doubly fed wind turbines participate in primary frequency modulation by reducing load and leaving standby, the rated power should be reduced by at least 6%. Only when the optimal power of the wind turbine is found can accurate load reduction be achieved, otherwise the load reduction will be excessive or insufficient. The optimal power is linked to the wind speed. Therefore, the equivalent wind speed of the wind turbine must be measured or evaluated to accurately reduce the load.

[0003] There are two wind speed measurement methods in the prior art. One is to install a wind speed measuring instrument on the wind turbine nacelle to measure the wind speed, and the other is to set up a wind speed measuring device outside the wind turbine body to evaluate the equivalent wind speed captured by the wind turbine. In these two methods, the measured wind speed does not represent the wind speed captured by the wind turbine, and only the wind speed of one point is captured, that is, there is an inaccurate measurement problem, which leads to errors in the calculated optimal power, which is easy to cause excessive load shedding to waste electricity, or insufficient load shedding to cause insufficient standby power, and fail to meet the primary frequency regulation requirements. Summary of the invention

[0004] In view of the defects of the prior art and the need for improvement, the present invention provides a primary frequency regulation control method, system and medium for a doubly fed wind turbine, the purpose of which is to determine the optimal power that the wind turbine should have under the current operating conditions based on the functional correspondence between wind speed, pitch angle, rotational speed and mechanical power, and on this basis perform fixed load reduction and apply primary frequency regulation control.

[0005] To achieve the above-mentioned object, according to one aspect of the present invention, a primary frequency regulation control method for a doubly-fed wind turbine is provided, comprising: S1, based on the mapping relationship between wind turbine power, pitch angle, wind turbine speed and wind speed, according to the collected wind turbine power, pitch angle and wind turbine speed, an equivalent wind speed is calculated, and a pitch angle compensation signal is calculated according to the grid-connected frequency, the preset load reduction power, the equivalent wind speed and the wind turbine power; S2, according to the pitch angle compensation signal, the wind turbine power and the wind turbine speed, a pitch angle reference signal and an electromagnetic torque reference signal are calculated; S3 , according to the collected electromagnetic power, output reactive power, three-phase voltage and electromagnetic torque reference signal of the wind turbine, a first drive signal is calculated, and according to the collected DC bus capacitor voltage and grid-side q-axis current of the wind turbine, a second drive signal is calculated; S4, the pitch angle of the wind turbine is controlled according to the pitch angle reference signal, the rotor-side PWM converter connected to the wind turbine rotor is driven according to the first drive signal, and the grid-side PWM converter connected to the power grid is driven according to the second drive signal to adjust the wind turbine speed, the active power and reactive power output by the wind turbine stator.

[0006] Furthermore, the calculation of the pitch angle compensation signal in S1 includes: calculating the difference between the optimal power corresponding to the equivalent wind speed and the preset load reduction power to obtain a reference power under the load reduction operation state; obtaining the compensation power after the grid-connected frequency is subjected to droop control, and taking the sum of the reference power under the load reduction operation state and the compensation power as the wind turbine reference power; and calculating the pitch angle compensation signal according to the wind turbine reference power and the wind turbine power.

[0007] Furthermore, the calculating of the pitch angle compensation signal according to the wind turbine reference power and the wind turbine power comprises: calculating the difference between the wind turbine reference power and the wind turbine power to obtain a power deviation, and obtaining the pitch angle compensation signal after the power deviation is subjected to proportional-integral control.

[0008] Furthermore, obtaining the compensation power after the grid-connected frequency is subjected to droop control includes: calculating the difference between the grid-connected frequency and the power frequency to obtain the frequency deviation, and obtaining the compensation power after the frequency deviation is subjected to proportional control.

[0009] Furthermore, the method further includes: when the pitch angle compensation signal is less than 0, limiting the pitch angle compensation signal to 0.

[0010] Furthermore, S2 includes: taking the optimal speed corresponding to the fan power as the fan reference speed, calculating the difference between the fan reference speed and the fan speed, and obtaining the speed deviation; obtaining the electromagnetic torque reference signal after the speed deviation is subjected to proportional-integral control; obtaining the pitch angle control signal after the speed deviation is subjected to proportional control, and calculating the sum of the pitch angle compensation signal and the pitch angle control signal to obtain the pitch angle reference signal.

[0011] Furthermore, it also includes: when the pitch angle control signal is less than 0, limiting the pitch angle control signal to 0.

[0012] According to another aspect of the present invention, a primary frequency regulation control system for a doubly-fed wind turbine is provided, characterized in that it comprises: a rotor-side PWM converter connected to the wind turbine rotor, and a grid-side PWM converter connected to the power grid; a load shedding frequency regulation controller for calculating an equivalent wind speed based on a mapping relationship between wind turbine power, pitch angle, wind turbine speed and wind speed, according to the collected wind turbine power, pitch angle and wind turbine speed, and calculating a pitch angle compensation signal according to the grid-connected frequency, a preset load shedding power, the equivalent wind speed and the wind turbine power; a wind turbine controller for calculating a pitch angle compensation signal according to the pitch angle compensation signal, the wind turbine power and the wind turbine speed. Angle reference signal and electromagnetic torque reference signal are obtained, and the pitch angle of the wind turbine is controlled according to the pitch angle reference signal; a rotor-side current and voltage controller is used to calculate a first drive signal according to the collected electromagnetic power, output reactive power, three-phase voltage and the electromagnetic torque reference signal of the wind turbine, and drive the rotor-side PWM converter according to the first drive signal; a grid-side current and voltage controller is used to calculate a second drive signal according to the collected DC bus capacitor voltage of the wind turbine and the grid-side q-axis current, and drive the grid-side PWM converter according to the second drive signal; and realize the adjustment of the wind turbine speed, the active power and the reactive power output by the wind turbine stator.

[0013] Furthermore, the pitch adjustment, load reduction and frequency regulation controller includes: an equivalent wind speed calculator, which is used to calculate the equivalent wind speed based on the mapping relationship between wind turbine power, pitch angle, wind turbine speed and wind speed, according to the collected wind turbine power, pitch angle and wind turbine speed; an optimal power calculator, which is used to calculate the optimal power corresponding to the equivalent wind speed; a first subtractor, which is used to calculate the difference between the optimal power corresponding to the equivalent wind speed and the preset load reduction power, and obtain the reference power under the load reduction operation state; a droop controller, which is used to perform droop control on the grid-connected frequency to obtain the compensation power; a first adder; which is used to calculate the sum of the reference power under the load reduction operation state and the compensation power to obtain the wind turbine reference power; a second subtractor, which is used to calculate the difference between the wind turbine reference power and the wind turbine power to obtain the power deviation; a first proportional integrator, which is used to perform proportional integral control on the power deviation to obtain the pitch angle compensation signal.

[0014] According to another aspect of the present invention, a computer-readable storage medium is provided, on which a computer program is stored, characterized in that when the program is executed by a processor, the primary frequency modulation control method of a doubly-fed wind turbine as described above is implemented.

[0015] In general, the above technical scheme conceived by the present invention can achieve the following beneficial effects: a doubly fed wind turbine primary frequency regulation control method is provided, which determines the optimal power of the wind turbine at the current wind speed based on the functional relationship between the wind turbine power, pitch angle, wind turbine speed and wind speed, obtains a more accurate optimal power, and on this basis, adjusts the pitch of the wind turbine to reduce the load, accurately reserves the standby power required for the primary frequency regulation, ensures that the wind turbine participates in the primary frequency regulation and responds in a timely manner, avoids energy waste caused by excessive load reduction, and avoids insufficient active power during frequency regulation caused by insufficient load reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A flow chart of a primary frequency modulation control method for a doubly-fed wind turbine provided by an embodiment of the present invention;

[0017] Figure 2 A block diagram of a primary frequency regulation control system for a doubly-fed wind turbine provided in an embodiment of the present invention;

[0018] Figure 3 A control principle diagram of a slurry adjustment load shedding frequency modulation controller provided in an embodiment of the present invention;

[0019] Figure 4 A control principle diagram of a droop controller in a slurry regulation load shedding and frequency modulation controller provided in an embodiment of the present invention;

[0020] Figure 5 A control schematic diagram of a fan controller provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0022] In the present invention, the terms "first", "second", etc. (if any) in the present invention and the accompanying drawings are used to distinguish similar objects but not necessarily to describe a specific order or sequence.

[0023] Figure 1 A flow chart of a primary frequency modulation control method for a doubly-fed wind turbine provided by an embodiment of the present invention. Figure 1 , combined with Figure 2-Figure 5 , the primary frequency modulation control method of the doubly fed wind turbine in this embodiment is described in detail, and the method includes operations S1 to S4.

[0024] Operation S1, based on the mapping relationship between wind turbine power, pitch angle, wind turbine speed and wind speed, calculates the equivalent wind speed according to the collected wind turbine power, pitch angle and wind turbine speed, and calculates the pitch angle compensation signal according to the grid-connected frequency, preset load reduction power, equivalent wind speed and wind turbine power.

[0025] by Figure 2 Taking the doubly-fed wind turbine primary frequency regulation control system shown in the figure as an example, in this embodiment, the slurry regulation load shedding frequency regulation controller in the system performs operation S1, such as Figure 3 According to an embodiment of the present invention, operation S1 includes sub-operations S11 to S14.

[0026] In sub-operation S11, based on the mapping relationship between wind turbine power, pitch angle, wind turbine speed and wind speed, the equivalent wind speed is calculated according to the collected wind turbine power, pitch angle and wind turbine speed.

[0027] The wind power captured by the wind turbine has a certain functional relationship with the pitch angle, wind turbine speed and wind speed, that is, P m =f(v,ω r ,β), where P m is the wind turbine power, β is the pitch angle, ω r is the wind turbine speed, and v is the wind speed. Therefore, based on the collected wind turbine power, pitch angle and wind turbine speed, the equivalent wind speed can be determined, which is completed by the equivalent wind speed calculator in the load shedding and frequency modulation controller.

[0028] In sub-operation S12, the difference between the optimal power corresponding to the equivalent wind speed and the preset load reduction power is calculated to obtain a reference power in the load reduction operation state.

[0029] Since the pitch angle β of the optimal working point in the optimal power tracking area and the constant speed area is 0. After the equivalent wind speed is determined, the equivalent wind speed and pitch angle 0 can be determined by the relationship P m =f(v,ω r ,β) calculates the optimal power corresponding to the equivalent wind speed, which is completed by the optimal power calculator in the slurry regulation load shedding and frequency regulation controller.

[0030] Further, the optimal power and the preset load reduction power P are calculated. deline The difference between them is the reference power under the load reduction operation state, and the operation is completed by the first subtractor in the load reduction and frequency regulation controller.

[0031] In sub-operation S13, the grid-connected frequency is subjected to droop control to obtain compensation power, and the sum of the reference power in the load-reduced operation state and the compensation power is used as the wind turbine reference power.

[0032] According to an embodiment of the present invention, obtaining the compensation power after the grid-connected frequency is subjected to droop control specifically includes: calculating the difference between the grid-connected frequency and the power frequency f to obtain the frequency deviation, and obtaining the compensation power after the frequency deviation is subjected to proportional control.

[0033] Specifically, the grid-connected frequency, for example, is compensated for by a droop controller in a load shedding frequency modulation controller. The structure of the droop controller is as follows: Figure 4 As shown, it includes a third subtractor and a first proportional device. The third subtractor is used to calculate the grid-connected frequency f ref The difference between the power frequency f and the power frequency f is used to obtain the frequency deviation and input it into the first proportional device. After proportional control, the first proportional device outputs the compensation power. The first adder adds the reference power under the load reduction operation state output by the first subtractor and the compensation power output by the first proportional device to obtain the fan reference power.

[0034] In sub-operation S14, a pitch angle compensation signal is calculated according to the wind turbine reference power and the wind turbine power.

[0035] According to an embodiment of the present invention, sub-operation S14 specifically includes: calculating the difference between the wind turbine reference power and the wind turbine power to obtain a power deviation, and obtaining a pitch angle compensation signal after the power deviation is subjected to proportional-integral control.

[0036] Specifically, for example, the difference between the wind turbine reference power and the wind turbine power is calculated by the second subtractor in the pitch adjustment load reduction frequency modulation controller to obtain the power deviation; after the power deviation passes through the first proportional integrator in the pitch adjustment load reduction frequency modulation controller, the first proportional integrator outputs the pitch angle compensation signal β cps .

[0037] According to an embodiment of the present invention, when the pitch angle compensation signal is less than 0, it is necessary to limit the pitch angle compensation signal to 0 to ensure that the pitch angle compensation signal is greater than or equal to 0.

[0038] Operation S2: calculating a pitch angle reference signal and an electromagnetic torque reference signal according to the pitch angle compensation signal, the wind turbine power and the wind turbine speed.

[0039] by Figure 2 Taking the doubly-fed wind turbine primary frequency regulation control system shown as an example, in this embodiment, operation S2 is performed by the wind turbine controller in the system. According to the embodiment of the present invention, operation S2 includes sub-operations S21 to S23.

[0040] In sub-operation S21, the optimal rotation speed corresponding to the fan power is used as the fan reference rotation speed, and the difference between the fan reference rotation speed and the fan rotation speed is calculated to obtain the rotation speed deviation.

[0041] Since the optimal speed of the fan is in a one-to-one correspondence with the fan power, the fan reference speed can be given based on the fan power, that is, the optimal speed corresponding to the fan power. This operation can be completed by the optimal speed calculator in the fan controller, such as Figure 5 As shown in the figure, the optimal speed calculator determines whether the fan is operating in the maximum speed area or the suboptimal power tracking area according to the input fan power, and gives the fan reference speed.

[0042] Further, for example, by using a fourth subtractor in the fan controller, the fan reference speed and the fan speed ω are calculated. r The difference between them is the speed deviation.

[0043] In sub-operation S22, the speed deviation is subjected to proportional-integral control to obtain an electromagnetic torque reference signal. Specifically, the speed deviation is input into a second proportional-integrator in the fan controller, and the electromagnetic torque reference signal T is obtained after proportional-integral control. emref .

[0044] In sub-operation S23, the rotation speed deviation is proportionally controlled to obtain a pitch angle control signal, and the sum of the pitch angle compensation signal and the pitch angle control signal is calculated to obtain a pitch angle reference signal.

[0045] Specifically, the speed deviation is input into the second proportional device in the wind turbine controller, and the pitch angle control signal is obtained after proportional control. According to an embodiment of the present invention, when the pitch angle control signal is less than 0, the pitch angle control signal needs to be limited to 0 to ensure that the pitch angle control signal is greater than or equal to 0. Further, the pitch angle control signal is input into the second adder, and the second adder calculates the pitch angle compensation signal β cps The pitch angle reference signal β is obtained by adding the pitch angle control signal ref .

[0046] Operation S3, calculates a first drive signal according to the collected electromagnetic power, output reactive power, three-phase voltage and electromagnetic torque reference signal of the wind turbine, and calculates a second drive signal according to the collected DC bus capacitor voltage and grid-side q-axis current of the wind turbine.

[0047] by Figure 2 Taking the doubly-fed wind turbine primary frequency modulation control system shown in the figure as an example, in this embodiment, operation S3 is performed by the rotor-side current and voltage controller and the grid-side current and voltage controller in the system. Specifically, the electromagnetic power P of the wind turbine collected is e , output reactive power Q, three-phase voltage u abc and electromagnetic torque reference signal T emref Input the rotor side current and voltage controller to obtain the first drive signal; collect the fan DC bus capacitor voltage U dc and the grid-side q-axis current i gq The grid-side current and voltage controller is input to obtain a second driving signal.

[0048] Operation S4 controls the pitch angle of the wind turbine according to the pitch angle reference signal, drives the rotor-side PWM converter connected to the wind turbine rotor according to the first drive signal, and drives the grid-side PWM converter connected to the power grid according to the second drive signal to adjust the wind turbine speed, the active power and the reactive power output by the wind turbine stator.

[0049] In this embodiment, the rotor of the doubly-fed wind turbine is electrically connected to the output end of the rotor-side PWM converter, and the stator of the doubly-fed wind turbine is connected to the power grid via a transformer; the input end of the grid-side PWM converter is connected to the capacitor through a DC bus and is connected to the input end of the rotor-side PWM converter at the same time; the output end of the grid-side PWM converter is connected to the transformer through a filter inductor and connected to the power grid.

[0050] by Figure 2 Taking the doubly-fed wind turbine primary frequency modulation control system shown in the figure as an example, the wind turbine controller is based on the pitch angle reference signal β output by it. ref To control the pitch angle of the wind turbine, the rotor-side current and voltage controller drives the rotor-side PWM converter based on the first drive signal outputted by the rotor-side current and voltage controller, and the grid-side current and voltage controller drives the grid-side PWM converter based on the second drive signal outputted by the grid-side current and voltage controller.

[0051] The rotor-side PWM converter and the rotor-side current and voltage control have two control objectives: one is to provide the current required for excitation to the rotor of the doubly-fed wind turbine to adjust the reactive power output by the stator; the other is to control the torque and speed of the doubly-fed wind turbine through the rotor current torque component, thereby controlling the active power output of the wind turbine. The main function of the grid-side PWM converter is to maintain the voltage stability of the DC bus and control the input power factor.

[0052] The embodiment of the present invention also provides a double-fed wind turbine primary frequency modulation control system, the structure block diagram of which is as follows: Figure 2-Figure 5 The system includes: a rotor-side PWM converter connected to the wind turbine rotor, and a grid-side PWM converter connected to the grid. The system also includes: a load shedding and frequency modulation controller for calculating the equivalent wind speed based on the mapping relationship between the wind turbine power, pitch angle, wind turbine speed and wind speed, according to the collected wind turbine power, pitch angle and wind turbine speed, and calculating the pitch angle compensation signal according to the grid-connected frequency, the preset load shedding power, the equivalent wind speed and the wind turbine power; a wind turbine controller for calculating the pitch angle reference signal and the electromagnetic torque reference signal according to the pitch angle compensation signal, the wind turbine power and the wind turbine speed, and controlling the pitch angle of the wind turbine according to the pitch angle reference signal; a rotor-side current and voltage controller for calculating the first drive signal according to the collected electromagnetic power, output reactive power, three-phase voltage and electromagnetic torque reference signal of the wind turbine, and driving the rotor-side PWM converter according to the first drive signal; a grid-side current and voltage controller for calculating the second drive signal according to the collected wind turbine DC bus capacitor voltage and grid-side q-axis current, and driving the grid-side PWM converter according to the second drive signal; and realizing the adjustment of the wind turbine speed, the active power and reactive power output by the wind turbine stator.

[0053] According to an embodiment of the present invention, a load shedding and frequency regulation controller includes: an equivalent wind speed calculator, which is used to calculate the equivalent wind speed based on the mapping relationship between wind turbine power, pitch angle, wind turbine speed and wind speed, according to the collected wind turbine power, pitch angle and wind turbine speed; an optimal power calculator, which is used to calculate the optimal power corresponding to the equivalent wind speed; a first subtractor, which is used to calculate the difference between the optimal power corresponding to the equivalent wind speed and the preset load shedding power, and obtain the reference power under the load shedding operation state; a droop controller, which is used to perform droop control on the grid-connected frequency to obtain the compensation power; a first adder, which is used to calculate the sum of the reference power and the compensation power under the load shedding operation state to obtain the wind turbine reference power; a second subtractor, which is used to calculate the difference between the wind turbine reference power and the wind turbine power to obtain the power deviation; a first proportional integrator, which is used to perform proportional integral control on the power deviation to obtain the pitch angle compensation signal.

[0054] The primary frequency regulation control system of the double-fed wind turbine in this embodiment is used to execute Figure 1-Figure 5 The primary frequency modulation control method of the doubly fed wind turbine shown in the Figure 1-Figure 5 The primary frequency regulation control system of the doubly-fed wind turbine in the illustrated embodiment is the same and will not be described in detail here.

[0055] The embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the following Figure 1-Figure 5 The primary frequency regulation control method of the doubly fed wind turbine is shown.

[0056] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for primary frequency modulation control of a doubly-fed wind turbine, characterized in that: include: S1, based on the mapping relationship between wind turbine power, pitch angle, wind turbine speed and wind speed, the equivalent wind speed is calculated according to the collected wind turbine power, pitch angle and wind turbine speed, and the pitch angle compensation signal is calculated according to the grid-connected frequency, the preset load reduction power, the equivalent wind speed and the wind turbine power; S2, calculating a pitch angle reference signal and an electromagnetic torque reference signal according to the pitch angle compensation signal, the wind turbine power and the wind turbine speed; S3, according to the collected electromagnetic power, output reactive power, three-phase voltage and the electromagnetic torque reference signal of the fan, calculate the first drive signal, according to the collected DC bus capacitor voltage of the fan and the grid side q The shaft current is used to calculate the second driving signal; S4, controlling the pitch angle of the wind turbine according to the pitch angle reference signal, driving the rotor-side PWM converter connected to the wind turbine rotor according to the first drive signal, and driving the grid-side PWM converter connected to the power grid according to the second drive signal, so as to adjust the wind turbine speed, the active power and the reactive power output by the wind turbine stator; The calculation of the pitch angle compensation signal in S1 includes: calculating the difference between the optimal power corresponding to the equivalent wind speed and the preset load reduction power to obtain the reference power under the load reduction operation state; obtaining the compensation power after the grid-connected frequency is subjected to droop control, and taking the sum of the reference power under the load reduction operation state and the compensation power as the wind turbine reference power; calculating the pitch angle compensation signal according to the wind turbine reference power and the wind turbine power; Calculating the pitch angle compensation signal according to the wind turbine reference power and the wind turbine power comprises: calculating the difference between the wind turbine reference power and the wind turbine power to obtain a power deviation, and obtaining the pitch angle compensation signal after the power deviation is subjected to proportional-integral control; The S2 includes: Taking the optimal speed corresponding to the fan power as the fan reference speed, calculating the difference between the fan reference speed and the fan speed to obtain the speed deviation; The electromagnetic torque reference signal is obtained after the speed deviation is controlled by proportional integral; The rotation speed deviation is proportionally controlled to obtain a pitch angle control signal, and the sum of the pitch angle compensation signal and the pitch angle control signal is calculated to obtain the pitch angle reference signal.

2. The primary frequency modulation control method of a doubly-fed wind turbine according to claim 1, characterized in that: The compensation power obtained after the grid-connected frequency is subjected to droop control includes: The difference between the grid-connected frequency and the power frequency is calculated to obtain a frequency deviation, and the frequency deviation is proportionally controlled to obtain the compensation power.

3. The primary frequency modulation control method of a doubly-fed wind turbine according to claim 1, characterized in that: Also includes: When the pitch angle compensation signal is less than 0, the pitch angle compensation signal is limited to 0.

4. The primary frequency modulation control method of a doubly-fed wind turbine according to claim 1, characterized in that: Also includes: When the pitch angle control signal is less than 0, the pitch angle control signal is limited to 0.

5. A double-fed wind turbine primary frequency modulation control system, characterized in that: A method for controlling a primary frequency modulation of a doubly-fed wind turbine according to any one of claims 1 to 4, comprising: a rotor-side PWM converter connected to a wind turbine rotor, and a grid-side PWM converter connected to a power grid; The load shedding and frequency modulation controller is used to calculate the equivalent wind speed based on the mapping relationship between the wind turbine power, pitch angle, wind turbine speed and wind speed, according to the collected wind turbine power, pitch angle and wind turbine speed, and calculate the pitch angle compensation signal according to the grid-connected frequency, the preset load shedding power, the equivalent wind speed and the wind turbine power; a wind turbine controller, configured to calculate a pitch angle reference signal and an electromagnetic torque reference signal according to the pitch angle compensation signal, the wind turbine power and the wind turbine speed, and control the pitch angle of the wind turbine according to the pitch angle reference signal; A rotor-side current and voltage controller, configured to calculate a first drive signal according to the collected electromagnetic power, output reactive power, three-phase voltage and electromagnetic torque reference signal of the fan, and drive the rotor-side PWM converter according to the first drive signal; The grid-side current and voltage controller is used to collect the DC bus capacitor voltage of the fan and the grid-side q shaft current, calculate a second drive signal, and drive the grid-side PWM converter according to the second drive signal; realize the adjustment of the fan speed, the active power and the reactive power output by the fan stator; The slurry adjustment load reduction frequency modulation controller comprises: The equivalent wind speed calculator is used to calculate the equivalent wind speed based on the mapping relationship between the wind turbine power, pitch angle, wind turbine speed and wind speed according to the collected wind turbine power, pitch angle and wind turbine speed; An optimal power calculator, used to calculate the optimal power corresponding to the equivalent wind speed; A first subtractor is used to calculate the difference between the optimal power corresponding to the equivalent wind speed and the preset load reduction power to obtain a reference power under the load reduction operation state; A droop controller, used for performing droop control on the grid-connected frequency to obtain compensation power; A first adder; used to calculate the sum of the reference power under the load reduction operation state and the compensation power to obtain the fan reference power; a second subtractor, used for calculating the difference between the wind turbine reference power and the wind turbine power to obtain a power deviation; The first proportional integrator is used to perform proportional integral control on the power deviation to obtain the pitch angle compensation signal.

6. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the primary frequency regulation control method of a doubly-fed wind turbine as described in any one of claims 1 to 4 is implemented.

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