Doubly-fed wind turbine generator voltage source control method, device, equipment and medium

Abstract

The invention discloses a doubly-fed wind turbine generator voltage source control method, a doubly-fed wind turbine generator voltage source control device, doubly-fed wind turbine generator equipment and a medium, and relates to the field of control. If the current SOC value of the energy storage system is smaller than the preset SOC threshold value, the wind turbine generator needs to be controlled to charge the energy storage system; when the power grid side fluctuates and the wind turbine generator is not off-grid or the wind turbine generator is off-grid suddenly during grid-connected operation, the output power of the wind turbine generator is adjusted according to the current phase angle fluctuation quantity of the wind turbine generator; and when the wind turbine generator is shut down and the wind turbine generator is off-grid, the energy storage system needs to be controlled to charge the wind turbine generator until the stator voltage of the wind turbine generator is within the preset stator voltage range. Considering that the energy storage system is free of pollution and the voltage source type wind turbine generator set can adjust the output power of the wind turbine generator set more quickly and accurately, the energy storage system and the voltage source technology are combined to provide quick support for the wind turbine generator set.

Description

Technical Field

[0001] The present invention relates to the field of control, and in particular to a voltage source control method, device, equipment and medium for a doubly-fed wind turbine generator set. Background Art

[0002] As the penetration rate of new energy in the power system continues to increase, the traditional power system dominated by synchronous machines is gradually transforming into a new power system. The characteristics of the power grid's "double highs" and "double peaks" are further highlighted, and security risks are increasing. In order to meet the dual requirements of energy green transformation and power security supply, new energy must assume the responsibility of actively supporting the operation of the power grid.

[0003] At present, wind turbines are mainly connected to the grid through power electronic devices. Traditional grid-following units cannot adapt to weak grid operation due to the phase-locked loop synchronization operation mode. In the scenario of high-proportion wind power access, safety and stability problems such as grid desynchronization, voltage collapse, and frequency instability will become more prominent. Voltage source technology can simulate the characteristics of synchronous units, so that power electronic devices can provide voltage and frequency support capabilities similar to synchronous machines to the grid, solving the problems of weak grid operation and grid instability of wind power systems. In addition, when the wind turbine is off-grid, diesel generators are mainly used to provide backup power, provide power to the auxiliary circuit system of the wind turbine, and realize static and dynamic debugging of the wind turbine and black start of the wind turbine. However, although diesel generators can provide starting power for wind turbines, they have slow response speed, poor controllability, pollute the environment, and cannot provide fast power support for wind turbines. They are not suitable for long-term operation on the side of wind turbines. Summary of the invention

[0004] The purpose of the present invention is to provide a voltage source control method, device, equipment and medium for a doubly-fed wind turbine. In this solution, through voltage source technology, when the frequency of the grid side or the voltage of the grid side fluctuates and the wind turbine is not off-grid, the wind turbine can independently support the grid voltage and frequency and adjust the output power of the wind turbine by controlling the stator voltage and rotor current of the machine side and the voltage and phase angle of the grid side through the voltage source technology. At the same time, when the wind turbine is suddenly disconnected during grid-connected operation, the pitch is controlled to achieve self-maintaining operation until the output power is less than the total load power of the unit; in addition, the energy storage system is used as a backup power supply. When the wind turbine is shut down and off-grid, the energy storage system will supply power to the wind turbine until the stator voltage of the wind turbine is within the preset stator voltage range, that is, until the wind turbine completes the black start, the energy storage system will be controlled to stop charging. Because the energy storage system has a fast response speed, flexible control and no pollution, it is more suitable for providing rapid support for wind turbines for a long time.

[0005] In order to solve the above technical problems, the present invention provides a voltage source control method for a doubly-fed wind turbine generator set, comprising:

[0006] Determine the current grid-connected state of the wind turbine generator set and collect the current SOC value of the energy storage system, wherein when the current SOC value is less than a preset SOC threshold, control the wind turbine generator set to charge the energy storage system;

[0007] If the current grid-connected state is that the frequency on the grid side or the voltage on the grid side does not fluctuate, the steps of determining the current grid-connected state of the wind turbine and collecting the current SOC value of the energy storage system are triggered;

[0008] If the current grid-connected state is that the frequency of the grid side or the voltage of the grid side fluctuates and the grid is not disconnected from the wind turbine generator set, then adjusting the output power of the wind turbine generator set according to the current phase angle fluctuation amount of the wind turbine generator set;

[0009] If the current grid-connected state is that the wind turbine generator set suddenly disconnects from the grid while in grid-connected operation, adjusting the output power of the wind turbine generator set according to the current phase angle fluctuation amount of the wind turbine generator set;

[0010] If the current grid-connected state is that the grid is disconnected from the wind turbine generator set and the wind turbine generator set is shut down, the energy storage system is controlled to charge the wind turbine generator set until the stator voltage of the wind turbine generator set is within a preset stator voltage range, and the energy storage system is controlled to stop charging the wind turbine generator set.

[0011] Optionally, adjusting the output power of the wind turbine generator set according to the current phase angle fluctuation amount of the wind turbine generator set includes:

[0012] Collecting the current angular velocity, current grid connection point voltage, current grid connection point current and current grid connection point phase angle of the wind turbine generator set;

[0013] Determine the current grid connection point active power and the current grid connection point reactive power of the wind turbine generator according to the current grid connection point voltage and the current grid connection point current;

[0014] Inputting the active power setting value and the current grid-connected point active power into the active power-frequency control loop to obtain the angular velocity setting value;

[0015] Performing a preset integration operation according to the angular velocity setting value to obtain the current phase angle fluctuation quantity;

[0016] The output power of the wind turbine generator set is adjusted based on the current phase angle fluctuation, the current grid connection point voltage, and the current grid connection point reactive power.

[0017] Optionally, the adjusting the output power of the wind turbine generator set based on the current phase angle fluctuation amount, the current grid connection point voltage, and the current grid connection point reactive power includes:

[0018] Collecting the current d-axis current and the current q-axis current of the rotor of the wind turbine generator set;

[0019] Inputting the reactive power setting value and the reactive power of the current grid connection point into the reactive power-voltage control loop to obtain the equivalent output electromotive force amplitude;

[0020] Determining a current stator d-axis voltage and a current stator q-axis voltage of the wind turbine generator set according to the current phase angle fluctuation amount and the current grid connection point voltage;

[0021] Inputting the current stator d-axis voltage, the current stator q-axis voltage and the electromotive force amplitude into a voltage loop to obtain a target rotor d-axis current and a target rotor q-axis current of the wind turbine generator set;

[0022] Inputting the target rotor d-axis current, the target rotor q-axis current, the current rotor d-axis current and the current rotor q-axis current into a current loop to obtain a current PWM modulation signal of a converter of a wind turbine generator set;

[0023] The current PWM modulation signal is transmitted to the converter to adjust the rotor a phase voltage, rotor b phase voltage, rotor c phase voltage, stator a phase voltage, stator b phase voltage, and stator c phase voltage of the wind turbine set to adjust the output power of the wind turbine set.

[0024] Optionally, determining the current grid connection point active power and the current grid connection point reactive power of the wind turbine generator according to the current grid connection point voltage and the current grid connection point current includes:

[0025] Determine the power factor of phase A on the grid side, the power factor of phase B on the grid side, and the power factor of phase C on the grid side;

[0026] The active power of the current grid connection point and the reactive power of the current grid connection point are determined according to the current grid connection point voltage, the current grid connection point current, the grid side A phase power factor, the grid side B phase power factor, the grid side C phase power factor, the active power determination formula and the reactive power determination formula.

[0027] Optionally, after controlling the wind turbine to charge the energy storage system when the current SOC value is less than a preset SOC threshold, the method further includes:

[0028] Determining whether the SOC value of the energy storage system after charging is equal to the rated SOC value, and the rated SOC value is greater than the preset SOC threshold;

[0029] If the SOC value of the energy storage system after charging is not equal to the rated SOC value, the step of controlling the wind turbine to charge the energy storage system when the current SOC value is less than a preset SOC threshold is triggered until the SOC value of the energy storage system after charging is equal to the rated SOC value.

[0030] Optionally, before controlling the energy storage system to charge the wind turbine generator set, the method further includes:

[0031] Determine whether the current SOC value of the energy storage system is less than a preset charging SOC threshold;

[0032] If the current SOC value of the energy storage system is not less than a preset charging SOC threshold, the step of controlling the energy storage system to charge the wind turbine is triggered.

[0033] Optionally, after controlling the energy storage system to stop charging the wind turbine generator set, the method further includes:

[0034] Determining whether the output power of the wind turbine generator set is less than the power of the total internal load of the wind turbine generator set;

[0035] If the output power of the wind turbine set is not less than the power of the total internal load of the wind turbine set, determine whether the current SOC value of the energy storage system is less than the rated SOC value; if the current SOC value of the energy storage system is less than the rated SOC value, trigger the step of controlling the energy storage system to charge the wind turbine set;

[0036] If the current SOC value of the energy storage system is equal to the rated SOC value, the speed change of the blades of the wind turbine set is determined based on the power difference between the output power of the wind turbine set and the power of the total load inside the wind turbine set, and the rotation of the blades of the wind turbine set is controlled according to the speed change until the power difference is within a preset difference range.

[0037] In order to solve the above technical problems, the present invention also provides a voltage source control device for a doubly-fed wind turbine generator set, comprising:

[0038] A determination unit, used to determine the current grid-connected state of the wind turbine and collect the current SOC value of the energy storage system, wherein when the current SOC value is less than a preset SOC threshold, the wind turbine is controlled to charge the energy storage system;

[0039] A trigger unit, configured to trigger the step of determining the current grid-connected state of the wind turbine and collecting the current SOC value of the energy storage system when the current grid-connected state is that the frequency of the grid side or the voltage of the grid side does not fluctuate;

[0040] A first regulating unit, configured to regulate the output power of the wind turbine generator set according to a current phase angle fluctuation amount of the wind turbine generator set when the current grid-connected state is that the frequency of the grid side or the voltage of the grid side fluctuates and the grid is not disconnected from the wind turbine generator set;

[0041] A second regulating unit is used to regulate the output power of the wind turbine generator set according to the current phase angle fluctuation amount of the wind turbine generator set when the current grid-connected state is that the wind turbine generator set is suddenly disconnected from the grid during grid-connected operation;

[0042] The third regulating unit is used to control the energy storage system to charge the wind turbine set when the current grid-connected state is that the grid is disconnected from the wind turbine set and the wind turbine set is shut down, until the stator voltage of the wind turbine set is within a preset stator voltage range, and then control the energy storage system to stop charging the wind turbine set.

[0043] In order to solve the above technical problems, the present invention further provides an electronic device, comprising:

[0044] Memory, used to store computer programs;

[0045] A processor is used to execute the computer program to implement the voltage source control method of the doubly-fed wind turbine generator system as described above.

[0046] In order to solve the above technical problem, the present invention also provides a computer-readable storage medium for storing a computer program, and when the computer program is executed by a processor, the voltage source control method of the doubly-fed wind turbine generator set as described above is implemented.

[0047] The purpose of the present invention is to provide a voltage source control method, device, equipment and medium for a doubly-fed wind turbine generator set. In this solution, an energy storage system is used as a backup power supply. When the wind turbine generator set is connected to the grid and the grid is stable, if the current SOC value of the energy storage system is less than a preset SOC threshold, the wind turbine generator set needs to be controlled to charge the energy storage system; when the frequency on the grid side or the voltage on the grid side fluctuates and the wind turbine generator set is not off the grid, the wind turbine generator set independently supports the grid voltage and frequency and adjusts the output power of the wind turbine generator set through the stator voltage and rotor current control of the machine side and the voltage and phase angle control of the grid side by the voltage source technology; when the wind turbine generator set is suddenly off the grid during grid-connected operation, the unit can use its total load as a load through the voltage source technology to achieve self-sustaining operation; if the wind turbine generator set is shut down and off the grid, the energy storage system will supply power to the wind turbine generator set until the stator voltage of the wind turbine generator set is within the preset stator voltage range, that is, until the wind turbine generator set completes a black start, and then the energy storage system will be controlled to stop charging. Because the energy storage system has a fast response speed, flexible control and no pollution, it is more suitable for providing rapid support for wind turbine generator sets for a long time. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0049] Figure 1 A process flow chart of a voltage source control method for a doubly-fed wind turbine generator system provided by the present invention;

[0050] Figure 2 A speed-torque curve diagram of a wind turbine generator set provided by the present invention;

[0051] Figure 3 A voltage source wind turbine control topology diagram provided by the present invention;

[0052] Figure 4 A schematic diagram of a black start control process of an energy storage system provided by the present invention;

[0053] Figure 5 A flow chart of a voltage source wind-storage collaborative control strategy provided by the present invention;

[0054] Figure 6 A schematic structural diagram of a voltage source control device for a doubly-fed wind turbine generator system provided by the present invention;

[0055] Figure 7 The present invention provides a schematic structural diagram of an electronic device. DETAILED DESCRIPTION

[0056] The core of the present invention is to provide a voltage source control method, device, electronic device and medium for a doubly-fed wind turbine. In this solution, through voltage source technology, when the frequency of the grid side or the voltage of the grid side fluctuates and the wind turbine is not off-grid, the wind turbine can independently support the grid voltage and frequency and adjust the output power of the wind turbine by controlling the stator voltage and rotor current of the machine side and the voltage and phase angle of the grid side through the voltage source technology. At the same time, when the wind turbine is suddenly disconnected during grid-connected operation, the variable pitch is controlled to achieve self-maintaining operation until the output power is less than the total load power of the unit; in addition, the energy storage system is used as a backup power supply. When the wind turbine is shut down and off-grid, the energy storage system will supply power to the wind turbine until the stator voltage of the wind turbine is within the preset stator voltage range, that is, until the wind turbine completes the black start, the energy storage system will be controlled to stop charging. Because the energy storage system has a fast response speed, flexible control and no pollution, it is more suitable for providing rapid support for wind turbines for a long time.

[0057] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0058] Please refer to Figure 1 , Figure 1 A process flow chart of a voltage source control method for a doubly-fed wind turbine provided by the present invention. The method comprises:

[0059] S11: Determine the current grid-connected state of the wind turbine and collect the current SOC value of the energy storage system, wherein when the current SOC value is less than a preset SOC threshold, control the wind turbine to charge the energy storage system;

[0060] S12: If the current grid-connected state is that the frequency on the grid side or the voltage on the grid side does not fluctuate, then triggering the steps of determining the current grid-connected state of the wind turbine and collecting the current SOC value of the energy storage system;

[0061] S13: If the current grid-connected state is that the frequency or voltage on the grid side fluctuates and the grid and the wind turbine generator set are not disconnected, then the output power of the wind turbine generator set is adjusted according to the current phase angle fluctuation amount of the wind turbine generator set;

[0062] S14: If the current grid-connected state is that the wind turbine generator set suddenly disconnects from the grid while being connected to the grid, then adjusting the output power of the wind turbine generator set according to the current phase angle fluctuation amount of the wind turbine generator set;

[0063] S15: If the current grid-connected state is that the grid and the wind turbine are disconnected and the wind turbine is shut down, the energy storage system is controlled to charge the wind turbine until the stator voltage of the wind turbine is within a preset stator voltage range, and the energy storage system is controlled to stop charging the wind turbine.

[0064] In the present invention, it is considered that in the prior art, when the wind turbine is connected to the grid, the traditional grid-following control (PQ (Power and Quality) control, constant power control) cannot provide active support to the power system like the synchronous machine. On the contrary, it will bring problems such as low inertia and low anti-interference ability to the power system. When the wind turbine is off-grid, the diesel generator serves as the backup power supply of the wind turbine. However, although the diesel generator can provide starting power for the wind turbine, it is necessary to start the diesel generator to generate electricity before it can supply power to the wind turbine. Therefore, it has a slow response speed and poor controllability, pollutes the environment, and cannot provide fast power support to the wind turbine. It is not suitable for long-term operation on the side of the wind turbine. Therefore, this application changes the grid-connected operation control of the wind turbine to voltage source control, changes the backup power supply of the wind turbine to the energy storage system, and determines the current state of the power grid and collects the current SOC (State Of Storage) of the energy storage system in real time. Charge, the battery's state of charge) value, so that when the current SOC value is less than the preset SOC threshold, the wind turbine is controlled to charge the energy storage system, ensuring that the energy storage system has enough power to charge the wind turbine when the wind turbine is off-grid. When the frequency or voltage on the grid side fluctuates and the grid and wind turbine are not disconnected, the wind turbine needs to adjust the stator voltage and rotor current on the machine side according to the voltage and phase angle on the grid side. Therefore, the output power of the wind turbine is adjusted according to the current phase angle fluctuation amount on the grid side to actively support the frequency fluctuation of the grid; but if the wind turbine is suddenly off-grid when it is running on the grid , it is necessary to use voltage source technology, the unit can use its own total load as the load to achieve self-sustaining operation, that is, the output power of the wind turbine is adjusted according to the current phase angle fluctuation on the grid side; if the wind turbine is shut down and off the grid, it is necessary to control the energy storage system to charge the wind turbine until the stator voltage of the wind turbine is within the preset stator voltage range. At this time, the black start of the wind turbine is completed, and then the energy storage system is controlled to stop charging the wind turbine to complete the black start process of the wind turbine. This solution utilizes the advantages of fast response speed, flexible control and pollution-free of the energy storage system, and can provide rapid support for wind turbines for a long time.

[0065] It should be noted that the wind turbines in this scheme can be either grid-connected wind turbines or voltage source wind turbines. Grid-connected wind turbines can be approximately regarded as controlled current sources with high parallel impedance. They need to detect the phase angle of the grid-connected point voltage and indirectly control the output power of the wind turbine or achieve voltage regulation by controlling the output current of the wind turbine. Traditional grid-connected units cannot provide support to the system like synchronous machines due to the use of phase-locked loop synchronization, and cannot adapt to weak network operation. In scenarios with a high proportion of wind power access, safety and stability problems such as grid loss, voltage collapse, and frequency instability will occur.

[0066] It should also be noted that 1. This scheme proposes a voltage source wind turbine control technology based on virtual synchronous control and droop control strategies. It can simulate the operating characteristics of synchronous units, directly control the voltage amplitude and phase angle of the wind turbine output, and independently build the grid voltage and frequency, which can improve the grid stability operation capability in a weak grid environment; 2. When a grid failure or other factors cause the wind turbine to be off-grid, a black start and unit self-sustaining operation strategy for voltage source wind turbines and energy storage systems is proposed by utilizing the stable performance, flexible control and fast response of the energy storage system. The stator voltage can be constructed through the energy storage system to complete the box transformer excitation, realizing the black start and self-sustaining operation functions of autonomous startup and operation in an off-grid state. 3. According to the voltage source technology, the main control needs to respond to the torque and power instructions fed back by the converter, and a speed control method based on voltage source technology for the wind turbine main control system is proposed. The converter power is used as a reference value to feed back to the main control, and the main control calculates the speed setting value; 4. Based on the voltage source technology and energy storage system, a voltage source wind-storage collaborative control strategy is proposed, which integrates the voltage source control technology and the energy storage system control with the wind turbine main control, realizing collaborative control strategies in multiple scenarios such as weak grids and off-grid, and improving the weak grid operation capability of wind turbines.

[0067] This embodiment provides a voltage source control method for a doubly-fed wind turbine generator set. In this solution, an energy storage system is used as a backup power source. When the wind turbine generator set is connected to the grid and the grid is stable, if the current SOC value of the energy storage system is less than a preset SOC threshold, the wind turbine generator set needs to be controlled to charge the energy storage system. When the frequency on the grid side or the voltage on the grid side fluctuates and the wind turbine generator set is not off-grid, the wind turbine generator set autonomously supports the grid voltage and frequency and adjusts the output power of the wind turbine generator set through the stator voltage and rotor current control on the machine side and the voltage and phase angle control on the grid side by the voltage source technology. When the wind turbine generator set is connected to the grid and suddenly goes off-grid, the unit can use its total load as the load through the voltage source technology to achieve self-sustaining operation. If the wind turbine generator set is shut down and off-grid, the energy storage system will supply power to the wind turbine generator set until the stator voltage of the wind turbine generator set is within the preset stator voltage range, that is, until the wind turbine generator set completes a black start, and then the energy storage system will be controlled to stop charging. Because the energy storage system has a fast response speed, flexible control, and is pollution-free, it is more suitable for providing rapid support for wind turbine generator sets for a long time.

[0068] Based on the above embodiments:

[0069] As an optional embodiment, adjusting the output power of the wind turbine generator set according to the current phase angle fluctuation amount of the wind turbine generator set includes:

[0070] Collect the current angular velocity, current grid connection point voltage, current grid connection point current and current grid connection point phase angle of the wind turbine;

[0071] Determine the current grid connection point active power and the current grid connection point reactive power of the wind turbine generator set according to the current grid connection point voltage and the current grid connection point current;

[0072] Input the active power setting value and the current grid-connected point active power into the active power-frequency control loop to obtain the angular velocity setting value;

[0073] Performing a preset integral operation according to the angular velocity setting value to obtain the current phase angle fluctuation quantity;

[0074] The output power of the wind turbine is adjusted based on the current phase angle fluctuation, the current grid connection point voltage, and the current grid connection point reactive power.

[0075] In the present invention, it is considered that the existing wind turbines are generally traditional grid-following control (PQ control), which cannot provide active support to the power system like synchronous machines. On the contrary, it will bring problems such as low inertia and low anti-interference ability to the power system; in addition, the current wind and solar resources are inversely distributed with the demand, and the "strip" distribution of the power grid and the long line characteristics lead to a lack of inter-grid regulation ability during centralized grid connection; with the continuous access of new energy sources leading to the weakening of local power grids, power grid failures and power system instability problems are becoming more and more prominent. In response to the problems of weak grid operation and grid instability, this solution selects a voltage source wind turbine as the wind turbine of this application, wherein the voltage source wind turbine is in the power grid. When the frequency on the grid side or the voltage on the grid side fluctuates, it is necessary to obtain the current angular velocity, current grid voltage, current grid current and current grid phase angle of the wind turbine in real time, and determine the current grid active power and current grid reactive power of the wind turbine according to the collected current grid voltage and current grid current, and then input the active power setting value and the current grid active power into the active-frequency control loop to obtain the angular velocity setting value, and perform a preset integral operation according to the angular velocity setting value to obtain the current phase angle fluctuation amount, and finally adjust the output power of the wind turbine based on the current phase angle fluctuation amount, the current grid voltage and the current grid reactive power. This solution uses voltage source technology to solve the problems of low inertia and weak damping presented by power electronic equipment.

[0076] As an optional embodiment, adjusting the output power of the wind turbine generator set based on the current phase angle fluctuation amount, the current grid connection point voltage, and the current grid connection point reactive power includes:

[0077] Collect the current rotor d-axis current and the current rotor q-axis current of the wind turbine;

[0078] Input the reactive power setting value and the reactive power of the current grid connection point into the reactive power-voltage control loop to obtain the equivalent output electromotive force amplitude;

[0079] Determine the current stator d-axis voltage and the current stator q-axis voltage of the wind turbine generator set according to the current phase angle fluctuation amount and the current grid connection point voltage;

[0080] The current stator d-axis voltage, the current stator q-axis voltage and the electromotive force amplitude are input into the voltage loop to obtain the target rotor d-axis current and the target rotor q-axis current of the wind turbine;

[0081] Inputting the target rotor d-axis current, the target rotor q-axis current, the current rotor d-axis current and the current rotor q-axis current into the current loop to obtain a current PWM (Pulse Width Modulation) modulation signal of the converter of the wind turbine generator set;

[0082] The current PWM modulation signal is transmitted to the converter to adjust the rotor a phase voltage, rotor b phase voltage, rotor c phase voltage, stator a phase voltage, stator b phase voltage, and stator c phase voltage of the wind turbine to adjust the output power of the wind turbine.

[0083] In the present invention, the voltage source technology is used to control the wind turbine set, that is, the current rotor d-axis current and the current rotor q-axis current of the wind turbine set are first collected; then the reactive power setting value and the current grid-connected point reactive power are input into the reactive-voltage control loop to obtain the equivalent output electromotive force amplitude, and then the current stator d-axis voltage and the current stator q-axis voltage of the wind turbine set are determined according to the current phase angle fluctuation amount and the current grid-connected point voltage, and the determined current stator d-axis voltage, current stator q-axis voltage and electromotive force amplitude are input into the voltage loop to obtain the target rotor d-axis current and target rotor q-axis current of the wind turbine set, and then the current phase angle fluctuation amount and the current grid-connected point voltage are determined according to the current phase angle fluctuation amount and the current grid-connected point voltage, and the current phase angle fluctuation amount and the current stator q-axis voltage are input into the voltage loop to obtain the target rotor d-axis current and target rotor q-axis current of the wind turbine set. The target rotor d-axis current, the target rotor q-axis current, the current rotor d-axis current and the current rotor q-axis current are input into the current loop to obtain the current PWM modulation signal of the converter of the wind turbine. Finally, the current PWM modulation signal is transmitted to the converter to adjust the rotor a-phase voltage, the rotor b-phase voltage, the rotor c-phase voltage, the stator a-phase voltage, the stator b-phase voltage and the stator c-phase voltage of the wind turbine, so as to accurately adjust the output power of the wind turbine. This scheme uses voltage source technology to solve the problems of low inertia and weak damping presented by power electronic equipment, while ensuring the stability of the output power adjustment process of the wind turbine.

[0084] It should be noted that the present application is based on voltage source technology and energy storage system, combined into a doubly-fed wind turbine control system, integrating voltage source strategy and energy storage system control strategy, which can improve the grid support capability, and realize black start of wind turbines in off-grid environments. Based on the virtual synchronous control strategy, the voltage amplitude and phase angle output by the wind turbine are directly controlled, the grid voltage and frequency are independently constructed, and the grid stability operation capability is improved; at the same time, when the wind turbine is off-grid due to grid failure or other factors, the energy storage system responds to the main control of the wind turbine, independently constructs the stator voltage, completes the box transformer excitation, and realizes the black start and self-maintaining operation functions of autonomous startup and operation in off-grid state.

[0085] It should also be noted that the performance of wind turbine output power lies in mechanical efficiency, also known as power coefficient C P (λ, β), mainly related to air density, fan radius, wind speed, fan speed, blade tip speed ratio and pitch angle. The mechanical power P converted from wind energy to electrical energy is shown in the following formula:

[0086] ; where ρ air is the air density, R is the fan radius, V w is the wind speed, C P (λ, β) represents the power efficiency of the wind turbine and is a nonlinear function of the tip speed ratio λ and the blade pitch angle β.

[0087] According to the motor principle, the mechanical torque of the wind turbine can be obtained as follows:

[0088] ;in, is the torque, ω t is the rotation speed, Characterizes the mechanical power P of the wind turbine.

[0089] It should also be noted that the speed-torque relationship curve of the wind turbine during operation is as follows: Figure 2 As shown in the figure, ω1 represents the grid-connected speed of the wind turbine, and ω2 represents the rated speed of the wind turbine. When the wind turbine reaches the grid-connected speed, the wind turbine starts to generate electricity, and the torque instantly reaches point B from point A. As the wind speed increases, the speed and torque increase proportionally, as shown in Figure 2 The BC section is shown. When the generator speed reaches the rated speed, if the wind speed continues to increase, it will enter the CD section constant speed operation, and the wind turbine will increase the power output by increasing the torque. When it reaches point D, the wind speed is the rated wind speed, and the wind turbine output power is the rated power, which is full output.

[0090] It should also be noted that in voltage source wind turbines, the converter of the wind turbine will actively adjust the power generation according to the grid disturbance, so the converter often fails to respond to the main control according to the optimal torque control (that is, the converter cannot determine the torque that needs to be adjusted according to the power fluctuation of the grid), resulting in abnormal control of the wind turbine. In order to solve this problem, it is necessary to optimize the control strategy of the wind turbine. When using voltage source technology control, the wind turbine needs to calculate the energy (current power fluctuation) used for converter power regulation in real time and transmit the energy information to the converter control system; at the same time, the converter also needs to transmit the grid frequency and the power and flag required for frequency regulation to the main control in real time. When the converter enters the voltage source control mode, the main control controls the speed of the unit with the power required by the converter as the target value, thereby realizing the coordinated control of the main control and converter of the voltage source wind turbine.

[0091] It should also be noted that, therefore, the mechanical power P in the formula is equal to the power fed back by the converter to the main control, that is: ; Among them, P abc is the grid-side output power of the wind turbine, U a is the grid-side phase A voltage, I a is the grid-side phase A current, cosφ a is the power factor of phase A on the grid side; U b is the grid-side phase B voltage, I b is the grid-side phase B current, cosφ b is the power factor of phase B on the grid side; U c is the grid-side phase C voltage, I c is the grid-side C-phase current, cosφ c is the power factor of phase C on the grid side. Substituting the above formula into the torque determination formula, the speed of the wind turbine can be obtained as: ;

[0092] Among them, λ is defined as follows: ;

[0093] In summary, when the wind turbine is in voltage source control mode, Figure 2 The speed in the middle BC section is controlled according to the speed, and the converter does not respond to the main control torque command at this time.

[0094] As an optional embodiment, determining the current grid connection point active power and the current grid connection point reactive power of the wind turbine generator system according to the current grid connection point voltage and the current grid connection point current includes:

[0095] Determine the power factor of phase A on the grid side, the power factor of phase B on the grid side, and the power factor of phase C on the grid side;

[0096] The current grid-connected point active power and the current grid-connected point reactive power are determined according to the current grid-connected point voltage, the current grid-connected point current, the grid-side A-phase power factor, the grid-side B-phase power factor, the grid-side C-phase power factor, the active power determination formula and the reactive power determination formula.

[0097] In the present invention, the specific process of determining the current grid-connected point active power and the current grid-connected point reactive power of the wind turbine generator set according to the current grid-connected point voltage and the current grid-connected point current is as follows: because the calculation of active power and reactive power are both related to the three-phase power factor, it is necessary to first determine the grid-side A-phase power factor, the grid-side B-phase power factor and the grid-side C-phase power factor, and then substitute the current grid-connected point voltage, the current grid-connected point current, the grid-side A-phase power factor, the grid-side B-phase power factor and the grid-side C-phase power factor into the active power determination formula and the reactive power determination formula respectively, so as to accurately determine the current grid-connected point active output power and the current grid-connected point reactive power.

[0098] It should be noted that wind turbines use virtual synchronization and droop control and other control forms to simulate the operating characteristics of synchronous units, directly control the voltage amplitude and phase angle of the wind turbine output, establish a connection between the system frequency and active power, and the voltage amplitude and reactive power, and can establish the machine-end voltage, support the frequency and voltage stability of the power grid, provide inertia and damping support to the system, and achieve autonomous synchronization with the power grid. The grid-connected characteristics of doubly-fed wind turbines are mainly reflected through the stator side, so the machine-side converter control realizes active support for the power grid, so that the stator side of the doubly-fed wind turbines appears as a voltage source characteristic to the outside. In terms of control structure: the machine-side converter control includes a three-layer control structure of "power-voltage-current". The power outer loop uses power loop control based on virtual synchronization and droop control characteristics to provide active support for the power grid. By simulating the rotor motion equation of the synchronous generator, as well as the speed regulator and excitation characteristics, the voltage reference phase is generated according to the rotor motion equation, and the reactive-voltage droop loop generates the reference voltage. The control topology diagram is as follows Figure 3 As shown, its control expression is as follows:

[0099] ; ;

[0100] Where ω0 is the synchronous angular velocity, ω ref is the angular velocity setting value, K pdroop is the active power-frequency droop adjustment coefficient, P ref is the active power setting value, P e is the actual value of active power; U s is the terminal voltage reference value, E s is the equivalent output electromotive force amplitude, K qdroop is the reactive power-voltage droop adjustment coefficient, Q ref is the reactive power setting value, Qe is the actual value of reactive power, Figure 3 where θ is the phase angle of the unit terminal voltage, 1 / s integral function, U abc_pcc is the grid voltage, u sd is the stator d-axis voltage, U sq is the stator q-axis voltage, I rd is the rotor d-axis current output by the voltage loop calculation, I rq is the rotor q-axis current output by the voltage loop calculation, i rd is the rotor d-axis current at the grid-connected point, irq is the rotor q-axis current at the grid-connected point, RSC is the converter of the wind turbine, and U ra is the rotor phase a voltage, u rd is the rotor b phase voltage, u rc is the rotor c phase voltage, u sa is the stator phase a voltage, u sb is the stator b phase voltage, u sc is the stator c-phase voltage. Figure 3 The voltage loop in the circuit is a voltage source control of the wind turbine. According to the voltage control reference value, the inner loop current control reference value is generated. The current loop generates the converter PWM control reference wave for reference value modulation.

[0101] As an optional embodiment, after controlling the wind turbine to charge the energy storage system when the current SOC value is less than the preset SOC threshold, the method further includes:

[0102] Determine whether the SOC value of the energy storage system after charging is equal to the rated SOC value, and whether the rated SOC value is greater than a preset SOC threshold;

[0103] If the SOC value of the energy storage system after charging is not equal to the rated SOC value, the step of controlling the wind turbine to charge the energy storage system when the current SOC value is less than the preset SOC threshold is triggered until the SOC value of the energy storage system after charging is equal to the rated SOC value.

[0104] In the present invention, after the wind turbine is controlled to charge the energy storage system when the SOC value is less than the preset SOC threshold, considering that the energy storage system has a rated SOC value, that is, the SOC value of the energy storage system when fully charged is the rated SOC value, in order to ensure the safety of the energy storage system, it is necessary to ensure that the energy storage system is not overcharged during the charging process after the wind turbine charges the energy storage system. Therefore, it is necessary to determine in real time whether the SOC value of the energy storage system after charging is equal to the rated SOC value. If the SOC value of the energy storage system after charging is not equal to the rated SOC value, the above charging process is continued until the SOC value of the energy storage system after charging is equal to the rated SOC value, and the wind turbine is controlled to stop charging the energy storage system. By ensuring that the energy storage system is not overcharged during the charging process, the safety of the solution is ensured.

[0105] It should be noted that during the operation of a wind turbine, due to grid failure or other factors, the wind turbine is shut down and out of power. It is impossible to obtain the status information of the wind turbine in time, which brings uncertainty risks to the wind turbine. The energy storage system has the characteristics of fast charging / discharging. When the wind turbine is off the grid, it can provide backup power to the main control and other auxiliary power circuits of the wind turbine in the first time, obtain the status information of the wind turbine in time, and ensure that the wind turbine is on standby in a safe state. At the same time, when the power grid needs to provide grid-connected support, the energy storage system slowly charges the DC bus on the grid side of the wind turbine converter, and the machine side establishes the stator voltage through voltage source technology to complete the machine side excitation and realize the black start of the wind turbine. The black start control flow chart of the energy storage system is shown as follows. Figure 4 As shown. The wind turbine then enters a self-sustaining operation state and can connect the generated power to the grid at any time to provide support for the grid. The energy storage capacity calculation formula is as follows: ; In the formula, E represents the capacity of the energy storage system, P1 represents the load power of the wind turbine, Ue represents the rated voltage of the energy storage system, η represents the energy storage charging efficiency, and T represents the usage time of the energy storage system.

[0106] As an optional embodiment, before controlling the energy storage system to charge the wind turbine generator set, the method further includes:

[0107] Determine whether the current SOC value of the energy storage system is less than a preset charging SOC threshold;

[0108] If the current SOC value of the energy storage system is not less than the preset charging SOC threshold, the step of controlling the energy storage system to charge the wind turbine is triggered.

[0109] In the present invention, before controlling the energy storage system to charge the wind turbine, it is considered that in order for the energy storage system to charge the wind turbine normally, it is necessary to ensure that its own SOC value is not less than a preset charging SOC value. If its own SOC value is less than the preset charging SOC value, charging failure may occur. Therefore, it is necessary to first determine whether the current SOC value of the energy storage system is less than the preset charging SOC threshold. If the current SOC value of the energy storage system is not less than the preset charging SOC threshold, the energy storage system can be controlled to charge the wind turbine. Conversely, if the current SOC value of the energy storage system is less than the preset charging SOC threshold, the energy storage system will not be controlled to charge the wind turbine, thereby ensuring the reliability of the charging process of the wind turbine.

[0110] As an optional embodiment, after controlling the energy storage system to stop charging the wind turbine generator set, the method further includes:

[0111] Determine whether the output power of the wind turbine generator set is less than the power of the total internal load of the wind turbine generator set;

[0112] If the output power of the wind turbine set is not less than the power of the total load inside the wind turbine set, determine whether the current SOC value of the energy storage system is less than the rated SOC value. If the current SOC value of the energy storage system is less than the rated SOC value, trigger the step of controlling the energy storage system to charge the wind turbine set.

[0113] If the current SOC value of the energy storage system is equal to the rated SOC value, the speed change of the wind turbine blades is determined based on the power difference between the output power of the wind turbine and the power of the total load inside the wind turbine, and the rotation of the wind turbine blades is controlled according to the speed change until the power difference is within a preset difference range.

[0114] In the present invention, after controlling the energy storage system to stop charging the wind turbine, the present solution also takes into account that the wind turbine is still in an off-grid state after the black start is completed. At this time, if the output power P of the wind turbine is 出 Less than the total load power P of the wind turbine 辅变 +P 箱变 +P 储能 , then the wind turbine will shut down due to the inability to maintain its own internal load, and the black start process needs to be repeated at this time; on the contrary, if the output power of the wind turbine itself is not less than the power of the total load of the wind turbine, it is necessary to determine whether the current SOC value of the energy storage system is less than 100% (rated SOC value). If it is equal to, the speed change of the wind turbine blades is determined based on the power difference between the output power of the wind turbine and the power of the total load of the wind turbine, and the rotation of the wind turbine blades is controlled according to the speed change until the difference is within the preset difference range, that is, the output power of the wind turbine is adjusted through pitch control to keep the difference between the output power of the wind turbine and the power of the total load inside the wind turbine within the preset range. The stability of the wind turbine in the self-sustaining operation state is guaranteed by real-time monitoring of the output power of the wind turbine, avoiding the shutdown of the wind turbine caused by the output power of the wind turbine being less than the power of the total load of the wind turbine.

[0115] It should be noted that under normal conditions, the wind turbine is still operating in the grid-following mode, and the unit controls the output power according to the maximum power point tracking (MPPT). In order to ensure that the capacity of the energy storage system meets the requirements of the wind turbine backup power supply or black start, the main control monitors the SOC value of the energy storage system in real time. When the SOC value is less than the Max threshold set by the system, the wind turbine will charge the energy storage system, and the charging is completed when the SOC value reaches 100% (rated SOC value).

[0116] In the voltage source control mode, the wind turbine has always simulated the characteristics of the synchronous machine and actively supported the grid voltage and frequency. At this time, the torque setting value and power setting value of the main control system are provided by the converter. When the frequency or voltage on the grid side fluctuates, the wind turbine converter side stator voltage, rotor current control and grid side voltage and phase angle control can realize autonomous support of grid voltage and frequency and timely guarantee the stable operation of the power system. In this process, the main control needs to calculate the speed setting value of the computer group in real time and quickly adjust the blade angle to meet the speed setting value requirements.

[0117] In black start mode, the energy storage system first enters the local black start mode, the energy storage system discharges, and the wind turbine main control system, auxiliary transformer system and box transformer control system are powered. Subsequently, the main control system issues a black start command, and the energy storage system enters the online black start mode. At this time, the main control system controls the variable pitch system to open the blades and increase the speed. The stator side of the wind turbine slowly builds up voltage, and the box transformer is excited. When the stator voltage reaches 10.5kV and the speed of the wind turbine meets the grid-connected speed, the converter closes, the output power of the wind turbine slowly increases, and the energy storage system slowly exits. In this process, it is ensured that the output power of the wind turbine plus the discharge power of the energy storage system meets the load power requirements of the auxiliary power circuit. When the energy storage system is completely exited, the main control controls the variable pitch system so that the output power of the wind turbine meets its own load power requirements and enters a self-sustaining operation state. The specific control block diagram is as follows Figure 5 As shown in the figure, this solution can enable wind turbines to quickly and autonomously support grid voltage and power under voltage source technology, which can improve the stable operation of wind turbines in weak grid environments and improve the stability of the power system. At the same time, the black start function of the unit is realized through the voltage source energy storage system, and self-sustaining operation control is achieved through coordination with the main control.

[0118] It should also be noted that 1. This solution is based on the virtual synchronous control and droop control strategy in voltage source technology, which can directly control the voltage amplitude and phase angle output by the wind turbine, with the goal of maintaining grid stability, and realize autonomous response to grid frequency / voltage changes, without relying on station-level frequency / voltage regulation instructions; 2. In voltage source technology control, the converter cannot respond to the main control torque instruction. By using the power torque calculation formula under conventional maximum power tracking, the converter torque and power are used as the main control reference value to control the speed of the wind turbine; 3. Taking advantage of the flexible control and fast response characteristics of the energy storage system, in off-grid scenarios, by controlling the discharge of the energy storage system, backup power is provided to the auxiliary circuit inside the wind turbine tower and the auxiliary circuit of the box transformer, so that the entire auxiliary power system of the wind turbine can operate normally. At the same time, the energy storage system discharges and cooperates with the voltage source technology to build the stator voltage and box transformer excitation, supplying power to the isolated grid and other loads in the field, and realizing the black start and self-sustaining operation functions of the wind turbine; 4. The main control system of the wind turbine is integrated with the voltage source control technology and the energy storage system control strategy to realize the coordinated control of the wind turbine in multiple scenarios such as weak power grid, rapid active support and off-grid status, thereby improving the wind turbine's ability to independently build a power grid and its self-coordinated control capabilities.

[0119] Please refer to Figure 6 , Figure 6 The present invention provides a schematic diagram of a voltage source control device for a double-fed wind turbine generator set. The device comprises:

[0120] The determination unit 11 is used to determine the current grid-connected state of the wind turbine and collect the current SOC value of the energy storage system, wherein when the current SOC value is less than a preset SOC threshold, the wind turbine is controlled to charge the energy storage system;

[0121] A trigger unit 12, used for triggering the step of determining the current grid-connected state of the wind turbine and collecting the current SOC value of the energy storage system when the current grid-connected state is that the frequency on the grid side or the voltage on the grid side does not fluctuate;

[0122] The first regulating unit 13 is used to regulate the output power of the wind turbine generator set according to the current phase angle fluctuation amount of the wind turbine generator set when the current grid-connected state is that the frequency of the grid side or the voltage of the grid side fluctuates and the grid and the wind turbine generator set are not disconnected;

[0123] The second regulating unit 14 is used to regulate the output power of the wind turbine generator set according to the current phase angle fluctuation amount of the wind turbine generator set when the current grid-connected state is that the wind turbine generator set is suddenly disconnected from the grid during grid-connected operation;

[0124] The third regulating unit 15 is used to control the energy storage system to charge the wind turbine when the current grid-connected state is that the grid and the wind turbine are disconnected and the wind turbine is shut down, until the stator voltage of the wind turbine is within a preset stator voltage range, and then control the energy storage system to stop charging the wind turbine.

[0125] The voltage source control device for a doubly-fed wind turbine set provided in this embodiment corresponds to the above method, and therefore has the same beneficial effects as the above method. Therefore, for the embodiments of the voltage source control device for a doubly-fed wind turbine set, please refer to the description of the embodiments of the method part, which will not be repeated here.

[0126] Please refer to Figure 7 , Figure 7 A schematic diagram of the structure of an electronic device provided by the present invention. The electronic device comprises:

[0127] A memory 20, for storing computer programs;

[0128] The processor 21 is used to execute a computer program to implement the voltage source control method of the doubly-fed wind turbine generator system as described above.

[0129] The electronic device provided in this embodiment may include but is not limited to a smart phone, a tablet computer, a laptop computer or a desktop computer.

[0130] Among them, the processor 21 may include one or more processing cores, such as a 4-core processor, an 8-core processor, etc. The processor 21 can be implemented in at least one hardware form of a digital signal processor (DSP), a field-programmable gate array (FPGA), and a programmable logic array (PLA). The processor 21 may also include a main processor and a coprocessor. The main processor is a processor for processing data in the awake state, also known as a central processing unit (CPU); the coprocessor is a low-power processor for processing data in the standby state. In some embodiments, the processor 21 may be integrated with a graphics processing unit (GPU), which is responsible for rendering and drawing the content to be displayed on the display screen. In some embodiments, the processor 21 may also include an artificial intelligence (AI) processor, which is used to process computing operations related to machine learning.

[0131] The memory 20 may include one or more computer-readable storage media, which may be non-transitory. The memory 20 may also include a high-speed random access memory, and a non-volatile memory, such as one or more disk storage devices, flash memory storage devices. In this embodiment, the memory 20 is at least used to store the following computer program 201, wherein, after the computer program is loaded and executed by the processor 21, it can implement the relevant steps of the voltage source control method of the doubly fed wind turbine disclosed in any of the aforementioned embodiments. In addition, the resources stored in the memory 20 may also include an operating system 202 and data 203, etc., and the storage method may be temporary storage or permanent storage. Among them, the operating system 202 may include Windows, Unix, Linux, etc. Data 203 may include but is not limited to the voltage source control method of the doubly fed wind turbine, etc.

[0132] In some embodiments, the electronic device may further include a display screen 22 , an input / output interface 23 , a communication interface 24 , a power source 25 , and a communication bus 26 .

[0133] Those skilled in the art will understand that Figure 7 The structure shown in the figure does not constitute a limitation on the electronic device, and may include more or fewer components than shown in the figure.

[0134] The purpose of this embodiment is to provide an electronic device, in which the memory 20 is used to store computer programs, and the processor 21 is used to implement the steps of the above-mentioned doubly-fed wind turbine voltage source control method when executing the computer program, so as to make the control process more efficient and accurate.

[0135] The present invention also provides an embodiment corresponding to a computer-readable storage medium, which is used to store a computer program, and when the computer program is executed by a processor, the voltage source control method of a doubly-fed wind turbine generator set as described above is implemented.

[0136] It is understandable that if the method in the above embodiment is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium to execute all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk and other media that can store program codes.

[0137] The computer-readable storage medium provided in this embodiment corresponds to the above method, and therefore has the same beneficial effects as the above method. Therefore, for the embodiments of the computer-readable storage medium part, please refer to the description of the embodiments of the method part, which will not be repeated here.

[0138] It should be noted that, in this specification, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0139] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A voltage source control method for a doubly-fed wind turbine generator system, characterized in that: include: Determine the current grid-connected state of the wind turbine generator set and collect the current SOC value of the energy storage system, wherein when the current SOC value is less than a preset SOC threshold, control the wind turbine generator set to charge the energy storage system; If the current grid-connected state is that the frequency on the grid side or the voltage on the grid side does not fluctuate, the steps of determining the current grid-connected state of the wind turbine and collecting the current SOC value of the energy storage system are triggered; If the current grid-connected state is that the frequency of the grid side or the voltage of the grid side fluctuates and the grid is not disconnected from the wind turbine generator set, then adjusting the output power of the wind turbine generator set according to the current phase angle fluctuation amount of the wind turbine generator set; If the current grid-connected state is that the wind turbine generator set suddenly disconnects from the grid while in grid-connected operation, adjusting the output power of the wind turbine generator set according to the current phase angle fluctuation amount of the wind turbine generator set; If the current grid-connected state is that the grid is disconnected from the wind turbine generator set and the wind turbine generator set is shut down, the energy storage system is controlled to charge the wind turbine generator set until the stator voltage of the wind turbine generator set is within a preset stator voltage range, and the energy storage system is controlled to stop charging the wind turbine generator set.

2. The voltage source control method of a doubly-fed wind turbine generator system according to claim 1, characterized in that: The step of adjusting the output power of the wind turbine generator set according to the current phase angle fluctuation amount of the wind turbine generator set comprises: Collecting the current angular velocity, current grid connection point voltage, current grid connection point current and current grid connection point phase angle of the wind turbine generator set; Determine the current grid connection point active power and the current grid connection point reactive power of the wind turbine generator according to the current grid connection point voltage and the current grid connection point current; Inputting the active power setting value and the current grid-connected point active power into the active power-frequency control loop to obtain the angular velocity setting value; Performing a preset integration operation according to the angular velocity setting value to obtain the current phase angle fluctuation quantity; The output power of the wind turbine generator set is adjusted based on the current phase angle fluctuation, the current grid connection point voltage, and the current grid connection point reactive power.

3. The voltage source control method of a doubly-fed wind turbine generator system according to claim 2, characterized in that: The step of adjusting the output power of the wind turbine generator set based on the current phase angle fluctuation amount, the current grid connection point voltage, and the current grid connection point reactive power includes: Collecting the current d-axis current and the current q-axis current of the rotor of the wind turbine generator set; Inputting the reactive power setting value and the reactive power of the current grid connection point into the reactive power-voltage control loop to obtain the equivalent output electromotive force amplitude; Determining a current stator d-axis voltage and a current stator q-axis voltage of the wind turbine generator set according to the current phase angle fluctuation amount and the current grid connection point voltage; Inputting the current stator d-axis voltage, the current stator q-axis voltage and the electromotive force amplitude into a voltage loop to obtain a target rotor d-axis current and a target rotor q-axis current of the wind turbine generator set; Inputting the target rotor d-axis current, the target rotor q-axis current, the current rotor d-axis current and the current rotor q-axis current into a current loop to obtain a current PWM modulation signal of a converter of a wind turbine generator set; The current PWM modulation signal is transmitted to the converter to adjust the rotor a phase voltage, rotor b phase voltage, rotor c phase voltage, stator a phase voltage, stator b phase voltage, and stator c phase voltage of the wind turbine set to adjust the output power of the wind turbine set.

4. The voltage source control method of a doubly-fed wind turbine generator system according to claim 2, characterized in that: The determining the current grid connection point active power and the current grid connection point reactive power of the wind turbine generator set according to the current grid connection point voltage and the current grid connection point current includes: Determine the power factor of phase A on the grid side, the power factor of phase B on the grid side, and the power factor of phase C on the grid side; The active power of the current grid connection point and the reactive power of the current grid connection point are determined according to the current grid connection point voltage, the current grid connection point current, the grid side A phase power factor, the grid side B phase power factor, the grid side C phase power factor, the active power determination formula and the reactive power determination formula.

5. The voltage source control method of a doubly-fed wind turbine generator system according to claim 1, characterized in that: After controlling the wind turbine to charge the energy storage system when the current SOC value is less than a preset SOC threshold, the method further includes: Determining whether the SOC value of the energy storage system after charging is equal to the rated SOC value, and the rated SOC value is greater than the preset SOC threshold; If the SOC value of the energy storage system after charging is not equal to the rated SOC value, the step of controlling the wind turbine to charge the energy storage system when the current SOC value is less than a preset SOC threshold is triggered until the SOC value of the energy storage system after charging is equal to the rated SOC value.

6. The voltage source control method of a doubly-fed wind turbine generator system according to claim 1, characterized in that: Before controlling the energy storage system to charge the wind turbine generator set, the method further includes: Determine whether the current SOC value of the energy storage system is less than a preset charging SOC threshold; If the current SOC value of the energy storage system is not less than a preset charging SOC threshold, the step of controlling the energy storage system to charge the wind turbine is triggered.

7. The voltage source control method for a doubly-fed wind turbine generator system according to any one of claims 1 to 6, characterized in that: After the energy storage system is controlled to stop charging the wind turbine generator set, the method further includes: Determining whether the output power of the wind turbine generator set is less than the power of the total internal load of the wind turbine generator set; If the output power of the wind turbine set is not less than the power of the total internal load of the wind turbine set, determine whether the current SOC value of the energy storage system is less than the rated SOC value; if the current SOC value of the energy storage system is less than the rated SOC value, trigger the step of controlling the energy storage system to charge the wind turbine set; If the current SOC value of the energy storage system is equal to the rated SOC value, the speed change of the blades of the wind turbine set is determined based on the power difference between the output power of the wind turbine set and the power of the total load inside the wind turbine set, and the rotation of the blades of the wind turbine set is controlled according to the speed change until the power difference is within a preset difference range.

8. A voltage source control device for a doubly-fed wind turbine generator set, characterized in that: include: A determination unit, used to determine the current grid-connected state of the wind turbine and collect the current SOC value of the energy storage system, wherein when the current SOC value is less than a preset SOC threshold, the wind turbine is controlled to charge the energy storage system; A trigger unit, configured to trigger the step of determining the current grid-connected state of the wind turbine and collecting the current SOC value of the energy storage system when the current grid-connected state is that the frequency of the grid side or the voltage of the grid side does not fluctuate; A first regulating unit, configured to regulate the output power of the wind turbine generator set according to a current phase angle fluctuation amount of the wind turbine generator set when the current grid-connected state is that the frequency of the grid side or the voltage of the grid side fluctuates and the grid is not disconnected from the wind turbine generator set; A second regulating unit is used to regulate the output power of the wind turbine generator set according to the current phase angle fluctuation amount of the wind turbine generator set when the current grid-connected state is that the wind turbine generator set is suddenly disconnected from the grid during grid-connected operation; The third regulating unit is used to control the energy storage system to charge the wind turbine set when the current grid-connected state is that the grid is disconnected from the wind turbine set and the wind turbine set is shut down, until the stator voltage of the wind turbine set is within a preset stator voltage range, and then control the energy storage system to stop charging the wind turbine set.

9. An electronic device, characterized in that: include: Memory, used to store computer programs; A processor, configured to execute the computer program to implement the voltage source control method for a doubly-fed wind turbine generator system according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: Used to store a computer program, which, when executed by a processor, implements the voltage source control method for a doubly-fed wind turbine generator set as claimed in any one of claims 1 to 7.

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