A networking control method, apparatus, device, medium, and program product

Abstract

The present application provides a network-forming control method, device, equipment, medium and program product, which relates to the field of electric power. Under the network-forming static var compensation strategy, the present application generates a virtual internal electromotive force through the intrinsic self-synchronization network-forming control technology based on the capacitor direct voltage; determines the synchronization phase angle of the virtual internal electromotive force according to the actual value of the DC voltage at the input end of the power electronic converter and the reference value corresponding to the DC voltage, and determines the amplitude of the virtual internal electromotive force according to the reactive power or voltage amplitude of the converter; determines the three-phase virtual internal electromotive force according to the synchronization phase angle and the amplitude of the virtual internal electromotive force, corrects the three-phase virtual internal electromotive force through the introduction of a virtual impedance switching control link to obtain the target three-phase virtual internal electromotive force, and generates a three-phase voltage regulation command for the converter according to the target three-phase virtual internal electromotive force. The converter executes the three-phase voltage regulation command to adjust the output AC voltage and prevent the converter from overcurrent. The present application has the advantages of simple control structure, pure voltage source characteristics, etc.

Description

Technical Field

[0001] The present application relates to the field of electric power, and in particular to a grid-forming control method, device, equipment, medium and program product. Background Art

[0002] With the advancement of the construction of a new power system, a large number of current-source type power electronic converters are connected to new energy power stations at the end of the power grid, making the power grid exhibit the characteristics of weak voltage support ability (the ability of the power grid to maintain voltage stability when disturbed decreases) and low inertia (the power grid is more sensitive to disturbances), which affects the power output of new energy power stations and even the stable operation of the power system. At present, the common solution is to connect a rotating device - a distributed synchronous condenser to the new energy power station, and enhance the stability of the system through the good inertia characteristics and voltage characteristics of the synchronous condenser.

[0003] However, the distributed synchronous condenser has problems such as high cost, complex system, difficult maintenance, and difficult site selection, and it is difficult to be widely applied in areas with a high proportion of new energy. Therefore, the concept of a grid-forming static var generator (SVG, also known as a static var compensator) has been proposed. Due to the limited current-carrying capacity of power electronic devices, in order to control the output current, the control algorithm of the static var generator usually adopts a control architecture of a VSG (Virtual Synchronous Generator) control outer loop + active damping + current inner loop, with a cumbersome control architecture and complex parameter design. The VSG control outer loop realizes the simulation of the inertia characteristics and excitation characteristics of the distributed synchronous condenser (making the static var generator exhibit behavior similar to that of a synchronous generator in the power grid); active damping is used to suppress the resonance that may occur in the LCL filter (or other filters) to ensure the stable operation of the system. The current inner loop is responsible for controlling the output current to ensure that the current meets the grid requirements. At the same time, due to the feedback links of current and voltage in the current inner loop, it will be affected by the delay of digital control (such as sampling delay, calculation delay, etc.), resulting in a risk of high-frequency oscillation, which will not only affect the stability of the system, but may also cause damage to the power grid and other equipment. Summary of the Invention

[0004] The present application provides a grid-forming control method, device, equipment, medium and program product. The present application constructs a grid-forming SVG control algorithm with pure voltage source characteristics. During the normal steady-state operation of the power electronic converter, the grid-forming SVG operates using a single-loop control strategy based on ultra-capacitor voltage intrinsic self-synchronization. The control structure is simple, without complex parameter design, and the traditional current inner loop is abandoned, which maximally ensures the voltage source characteristics (the ability to stably provide a constant voltage) of the grid-forming SVG and has strong reactive power support ability (the ability to provide or absorb reactive power to the power grid), and can effectively solve the problems existing in the prior art.

[0005] The present application provides a grid-forming control method, which is used to adjust the output voltage of a power electronic converter. The power electronic converter is used to convert the input DC voltage into an AC voltage and input it into the power system. The grid-forming control method includes:

[0006] Under the grid-forming static var compensation strategy, a virtual internal electromotive force for adjusting the output voltage of the power electronic converter is generated through the intrinsic self-synchronizing grid-forming control technology based on the DC voltage of the capacitor;

[0007] According to the actual value of the DC voltage at the input end of the power electronic converter and the reference value corresponding to the DC voltage, the synchronization phase angle of the virtual internal electromotive force is determined. The synchronization phase angle is used to adjust the phase of the AC voltage output by the power electronic converter;

[0008] According to the reactive power output by the power electronic converter or the voltage amplitude of the power system, the amplitude of the virtual internal electromotive force is determined;

[0009] According to the synchronization phase angle and the amplitude of the virtual internal electromotive force, a three-phase virtual internal electromotive force is determined;

[0010] Through the switching virtual impedance algorithm, the three-phase virtual internal electromotive force is corrected to obtain a target three-phase virtual internal electromotive force, and a three-phase voltage regulation command for the AC voltage output by the power electronic converter is determined according to the target three-phase virtual internal electromotive force;

[0011] The three-phase voltage regulation command is sent to the power electronic converter, so that the power electronic converter executes the three-phase voltage regulation command to adjust the output AC voltage.

[0012] According to the grid-forming control method provided by the present application, the determining the synchronization phase angle of the virtual internal electromotive force according to the actual value of the DC voltage at the input end of the power electronic converter and the reference value corresponding to the DC voltage includes:

[0013] The synchronization phase angle of the virtual internal electromotive force is determined by the following formula (1):

[0014] (1)

[0015] Wherein, represents the synchronization phase angle, represents the angular velocity of the virtual synchronous machine, J represents the inertia time constant, D represents the damping coefficient, K DW represents the angular velocity proportionality coefficient of the virtual synchronous machine, represents the control proportionality coefficient of the DC voltage at the input end of the power electronic converter, V dc-refRepresents the reference value of the DC voltage at the input of the power electronic converter, V dc-AVG Represents the actual value of the DC voltage at the input of the power electronic converter Represents the active power output by the power electronic converter Represents the frequency reference value, and s represents the Laplace differential operator

[0016] According to the grid-forming control method provided by the present application, the control proportional coefficient of the DC voltage at the input of the power electronic converter is determined by the following formula (2):

[0017] (2)

[0018] Wherein Represents the set value of the control proportional coefficient of the DC voltage at the input of the power electronic converter Represents The difference between And Represents the threshold value corresponding to the angular velocity of the virtual synchronous machine Represents The difference between And the corresponding threshold value Represents the change amplitude of the DC voltage at the input of the power electronic converter Represents the threshold value corresponding to the change amplitude of the DC voltage at the input of the power electronic converter

[0019] According to the grid-forming control method provided by the present application, the three-phase virtual internal potential is corrected by the virtual impedance switching algorithm to obtain the target three-phase virtual internal potential, and the three-phase voltage regulation command for the AC voltage output by the power electronic converter is determined according to the target three-phase virtual internal potential, including:

[0020] If the change amplitude of the instantaneous value of the system voltage of the power system is greater than the preset voltage difference threshold, or the instantaneous value of the three-phase current output by the power electronic converter is greater than the preset current threshold, the additional voltage increment value corresponding to each phase of the internal potential in the three-phase virtual internal potential is determined according to the virtual resistance, virtual reactance in the grid-forming control method and the three-phase current output by the power electronic converter, and the additional voltage increment value is used to correct the three-phase virtual internal potential;

[0021] Determine the sum value of each phase of the internal potential in the three-phase virtual internal potential and the corresponding additional voltage increment value to obtain the target three-phase virtual internal potential;

[0022] Modulate the target three-phase virtual internal potential by pulse width modulation technology to obtain the three-phase voltage regulation command

[0023] According to the network-forming control method provided by the present application, determining the additional voltage increment value corresponding to each phase of the internal potential in the three-phase virtual internal potential according to the virtual resistance, virtual reactance in the network-forming control method, and the three-phase current output by the power electronic converter includes:

[0024] For each phase of the internal potential in the three-phase virtual internal potential, according to the virtual resistance, the virtual reactance, and the three-phase current output by the power electronic converter, determine the corresponding additional voltage increment value through the following formula (3);

[0025] (3)

[0026] where, represents the additional voltage increment value, represents the virtual resistance, represents the virtual reactance, represents the three-phase current output by the power electronic converter, represents the time constant, and s represents the Laplace differential operator.

[0027] According to the network-forming control method provided by the present application, the excitation control link of the network-forming control method supports a reactive power control mode and a voltage control mode, and the AC voltage output by the power system is a three-phase positive-sequence voltage; determining the amplitude of the virtual internal potential according to the reactive power output by the power electronic converter, or the system voltage amplitude of the power system, includes:

[0028] If the reactive power control mode is adopted in the excitation control link, determine the amplitude of the virtual internal potential according to the actual value of the reactive power output by the power electronic converter and the reference value corresponding to the reactive power, so as to achieve constant reactive power control (maintaining the consistency between the actual value and the reference value of the reactive power);

[0029] If the voltage control mode is adopted in the excitation control link, determine the amplitude of the virtual internal potential according to the actual value of the three-phase positive-sequence voltage output by the power system and the reference value corresponding to the three-phase positive-sequence voltage, so as to achieve constant voltage control (realizing voltage stability control).

[0030] According to the network-forming control method provided by the present application, determining the three-phase virtual internal potential according to the synchronous phase angle and the amplitude of the virtual internal potential includes:

[0031] Through the following formula (4), determine the three-phase virtual internal potential according to the synchronous phase angle and the amplitude of the virtual internal potential:

[0032] (4)

[0033] where, represents the synchronous phase angle, represents the amplitude of the virtual internal electromotive force, 、 and represents the three-phase virtual internal electromotive force.

[0034] The present application also provides a network-forming control device for regulating the output voltage of a power electronic converter, which is used to convert the input DC voltage into an AC voltage and input it into the power grid. The network-forming control device includes:

[0035] A generating module, configured to generate a virtual internal electromotive force for regulating the output voltage of the power electronic converter through an intrinsic self-synchronizing network-forming control technology based on the DC voltage of the capacitor under the network-forming static var compensation strategy;

[0036] A first determining module, configured to determine the synchronous phase angle of the virtual internal electromotive force according to the actual value of the DC voltage at the input end of the power electronic converter and the reference value corresponding to the DC voltage, where the synchronous phase angle is used to regulate the phase of the AC voltage output by the power electronic converter;

[0037] A second determining module, configured to determine the amplitude of the virtual internal electromotive force according to the reactive power output by the power electronic converter or the system voltage amplitude of the power system;

[0038] A third determining module, configured to determine the three-phase virtual internal electromotive force according to the synchronous phase angle and the amplitude of the virtual internal electromotive force;

[0039] A fourth determining module, configured to correct the three-phase virtual internal electromotive force through a switched virtual impedance algorithm to obtain a target three-phase virtual internal electromotive force, and determine a three-phase voltage regulation command for the AC voltage output by the power electronic converter according to the target three-phase virtual internal electromotive force;

[0040] A sending module, configured to send the three-phase voltage regulation command to the power electronic converter, so that the power electronic converter executes the three-phase voltage regulation command to adjust the output AC voltage.

[0041] The present application also provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, it implements a network-forming control method as described in any one of the above.

[0042] The present application also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it implements a network-forming control method as described in any one of the above.

[0043] The present application also provides a computer program product, including a computer program, which, when executed by a processor, implements a network construction control method as described in any one of the above.

[0044] The present application provides a network construction control method, device, equipment, medium and program product. In the present application, a network construction type SVG control strategy (network construction type static var compensation strategy) is generally adopted to adjust the output voltage of a power electronic converter. First, through an intrinsic self-synchronization network construction control technology based on capacitor direct voltage, a virtual internal electromotive force for adjusting the output voltage of the power electronic converter is generated; then, according to the actual value of the DC voltage at the input end of the power electronic converter and the reference value corresponding to the DC voltage, the synchronous phase angle of the virtual internal electromotive force is determined, and according to the reactive power output by the power electronic converter or the voltage amplitude of the power system where the power electronic converter is located, the amplitude of the virtual internal electromotive force is determined; then, according to the synchronous phase angle and the amplitude of the virtual internal electromotive force, a three-phase virtual internal electromotive force is determined, and the three-phase virtual internal electromotive force is corrected through a switching virtual impedance algorithm to obtain a target three-phase virtual internal electromotive force, and according to the target three-phase virtual internal electromotive force, a three-phase voltage regulation command for the AC voltage output by the power electronic converter is determined, and the three-phase voltage regulation command is sent to the power electronic converter, so that the power electronic converter executes the three-phase voltage regulation command to adjust the output AC voltage. The present application constructs a network construction type SVG control algorithm with pure voltage source characteristics. During the normal steady-state operation of the power electronic converter, the network construction type SVG operates using a VSG single-loop control strategy, the control structure is simple, no complex parameter design is required, and the traditional current inner loop is abandoned, which maximally ensures the voltage source characteristics (the ability to stably provide a constant voltage) of the network construction type SVG, has a strong reactive power support ability (the ability to provide or absorb reactive power to the power grid), and there is no high-frequency resonance risk in the full frequency band. At the same time, the present application adopts a virtual impedance switching algorithm to input a virtual impedance control link during the transient operation process to prevent the converter from overcurrent, which can effectively solve the problems existing in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0046] Figure 1 is a flowchart of a network construction control method shown in an embodiment of the present application;

[0047] Figure 2 is a control schematic diagram of a network construction type SVG control method shown in an embodiment of the present application;

[0048] Figure 3 It is a structural block diagram of a network-constructing control device shown in an embodiment of the present application;

[0049] Figure 4 It is a schematic diagram of the physical structure of an electronic device shown in an embodiment of the present application. Detailed implementation manners

[0050] To make the objectives, technical solutions, and advantages of the present application clearer, the technical solutions in the present application will be clearly and completely described below with reference to the accompanying drawings in the present application. Apparently, the described embodiments are some but not all of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the protection scope of the present application.

[0051] To overcome the problems in the prior art, the present application provides a new network-constructing SVG control method (i.e., a network-constructing control method provided by the present application), which operates using a VSG single-loop control strategy, has a simple control structure, does not require complex parameter design, abandons the traditional current inner loop, maximally ensures the voltage source characteristics of the network-constructing SVG, and has a strong reactive power support ability.

[0052] The execution subject of the method of the present application is a network-constructing control device, which is essentially a control device based on a network-constructing SVG.

[0053] The method of the present application is used to adjust the output voltage of a power electronic converter located at the end of a power system, and the power electronic converter is used to convert the input DC voltage into an AC voltage and input it into the power system.

[0054] Figure 1 It is a flowchart of a network-constructing control method shown in an embodiment of the present application. Referring to Figure 1 , the method of the present application may include the following steps:

[0055] Step 101: Under the network-constructing static var compensation strategy, generate a virtual internal electromotive force for adjusting the output voltage of the power electronic converter through the intrinsic self-synchronizing network-constructing control technology based on capacitor direct voltage.

[0056] Among them, the intrinsic self-synchronizing network-forming control technology based on capacitor direct voltage combines the advantages of capacitor direct voltage control and network-forming control technology. This technology realizes the self-synchronizing control of power electronic converters by using the DC voltage of the capacitor as the intrinsic reference. The capacitor has the functions of energy storage and voltage stabilization. The capacitor DC voltage control refers to providing a stable energy source for the power electronic converter by precisely controlling the DC voltage of the capacitor. Based on the reference of the capacitor DC voltage, the power electronic converter can achieve self-synchronizing control, that is, the power electronic converter does not need to rely on the phase information of the external power grid, but adjusts according to its own voltage and current states to maintain synchronization with the power grid.

[0057] In this embodiment, the network-forming control device adopts the network-forming SVG control method. Through the intrinsic self-synchronizing network-forming control technology based on capacitor direct voltage, a stable AC electromotive force is constructed, which can provide non-delay synchronous reactive power support when the voltage of the power electronic converter fluctuates. The network-forming control device compensates the reactive power in the power grid by controlling the AC voltage generated by its inverter.

[0058] Among them, the network-forming control method adopted by the network-forming control device is different from the traditional grid-following control method. The grid-following control method simply follows the grid fluctuations and passively outputs reactive power, while the network-forming control method can actively provide voltage support and reactive power compensation for the power grid, thereby improving the stability of the power system and the power quality.

[0059] In this embodiment, the virtual synchronous machine control technology is also used when generating the virtual internal potential. The virtual synchronous machine control technology is a control technology used to simulate the behavior of synchronous generators. Its core is to use inverters to simulate the operating characteristics of synchronous generators. Traditional synchronous generators rely on mechanical motion and electromagnetic induction to generate electrical energy, while the virtual synchronous machine control technology simulates these characteristics through power electronic devices. Through precise control algorithms, stable control of the power system frequency and voltage can be achieved, thereby improving the stability and reliability of the entire power system.

[0060] Step 102: Determine the synchronous phase angle of the virtual internal potential according to the actual value of the DC voltage at the input end of the power electronic converter and the reference value corresponding to the DC voltage. The synchronous phase angle is used to adjust the phase of the AC voltage output by the power electronic converter.

[0061] Figure 2 is the control schematic diagram of a network-forming SVG control method shown in an embodiment of the present application. In Figure 2Among them, the part within the upper square box represents the main circuit where the converter is located, and the part within the lower square box represents the network-forming control device of this application. The part to the left of the arm reactance is the power electronic converter, which converts the DC voltage output by the new energy power station into an AC voltage and inputs it into the power grid (the channel for transmitting electric energy) through the 35KV busbar. In this application, the power electronic converter outputs three-phase voltage, represents three-phase voltage, / / represents three-phase current. represents the resistance in the power grid, represents the reactance in the power grid, / / represents the current in the power grid. The assessment point is used to monitor data such as current and voltage in the power grid. The control logic inside the network-forming control device is as shown in Figure 2 the control part (including the active control outer loop, reactive control outer loop, emergency current limiting measure, pulse width modulation PWM).

[0062] Referring to Figure 2 the active control link (power synchronization control link) in, in one implementation, step 102 may include:

[0063] Determine the synchronous phase angle of the virtual internal potential through the following formula:

[0064]

[0065] where, represents the synchronous phase angle, represents the angular velocity of the virtual synchronous machine, J represents the inertia time constant, D represents the damping coefficient, K DW represents the angular velocity proportionality coefficient of the virtual synchronous machine, represents the control proportionality coefficient of the DC voltage at the input of the power electronic converter, V dc-ref represents the reference value of the DC voltage at the input of the power electronic converter, V dc-AVG represents the actual value of the DC voltage at the input of the power electronic converter, represents the active power output by the power electronic converter, represents the frequency reference value, s represents the Laplace differential operator.

[0066] Among them, the virtual synchronous machine can be understood as a virtual synchronous generator simulated through virtual synchronous machine control technology.

[0067] In this embodiment, in order to ensure that the power electronic converter outputs as much active power as possible, the control proportionality coefficient K of the DC voltage at the input of the power electronic converterv It can be adjusted according to the actual value of the DC voltage at the input end of the power electronic converter and the angular velocity of the virtual synchronous machine. For adjustment.

[0068] Specifically, the control proportional coefficient can be determined by the following formula:

[0069]

[0070] Wherein, represents the set value of the control proportional coefficient of the DC voltage at the input end of the power electronic converter, represents the difference between and represents the threshold value corresponding to the angular velocity of the virtual synchronous machine, represents the difference between and represents the change amplitude of the DC voltage at the input end of the power electronic converter, represents the threshold value corresponding to the change amplitude of the DC voltage at the input end of the power electronic converter.

[0071] In this embodiment, when the condition of is satisfied, it is considered that the power electronic converter needs more active power support. At this time, the control of the DC voltage of the power electronic converter takes effect, and the value of K v is taken as , so as to control the DC voltage at the input end of the power electronic converter to the set value.

[0072] When the condition of is satisfied, it is considered that the power electronic converter needs more active power support, and at the same time, there is margin in the DC voltage at the input end of the power electronic converter. At this time, the control of the DC voltage of the power electronic converter fails, and the active power output based on inertia support is allowed to be output to the limit. The power electronic converter will output as much active power as possible to support the stable operation of the power grid. Among them, inertia support means that the virtual synchronous machine simulates the inertia characteristics of a traditional synchronous generator. The active power output to the limit means that when the power electronic converter meets specific conditions, it breaks through the conventional control limit and outputs active power with the maximum capacity of the device.

[0073] When neither nor is satisfied, it is considered that although the power electronic converter needs active power support, the DC voltage at the input end is already relatively high and needs to be controlled to avoid overvoltage and undervoltage. At this time, the control of the DC voltage of the power electronic converter takes effect again, and the DC voltage at the input end of the power electronic converter is controlled to a preset threshold value. in a certain interval near ± ), to maintain the voltage stability and system security, where can be set according to actual requirements.

[0074] Step 103: Determine the amplitude of the virtual internal electromotive force according to the reactive power output by the power electronic converter or the system voltage amplitude of the power system.

[0075] In this embodiment, the virtual excitation control link includes two control links, namely, a reactive power control closed-loop and a voltage control closed-loop. That is, the excitation control link of the grid-forming control method supports the reactive power control mode and the voltage control mode. The AC voltage output by the power electronic converter is a three-phase positive-sequence voltage, and the AC voltage output by the power system is a three-phase positive-sequence voltage.

[0076] Correspondingly, referring to Figure 2 in the outer loop of reactive power control, step 103 may include:

[0077] Step 1031: If the reactive power control mode is adopted in the excitation control link, determine the amplitude of the virtual internal electromotive force according to the actual value of the reactive power output by the power electronic converter and the reference value corresponding to the reactive power;

[0078] Step 1032: If the voltage control mode is adopted in the excitation control link, determine the amplitude of the virtual internal electromotive force according to the actual value of the three-phase positive-sequence voltage output by the power system and the reference value corresponding to the three-phase positive-sequence voltage.

[0079] In this embodiment, it will be determined in advance whether to adopt the reactive power control mode or the voltage control mode in the virtual excitation control link according to the voltage interval where the AC voltage output by the power electronic converter is located. In other words, if the AC voltage output by the power electronic converter is in voltage interval 1, the reactive power control mode is adopted; if the AC voltage output by the power electronic converter is in voltage interval 2, the voltage control mode is adopted. Voltage interval 1 is different from voltage interval 2. Voltage interval 1 and voltage interval 2 can be set according to actual requirements.

[0080] Specifically, referring to Figure 2 , if the reactive power control mode is adopted in the excitation control link, then the amplitude of the virtual internal electromotive force , if the voltage control mode is adopted in the excitation control link, then the amplitude of the virtual internal electromotive force , where is the reactive power control integral coefficient, is the reactive power control proportional coefficient, s represents the Laplace differential operator, represents the reference value corresponding to the reactive power output by the power electronic converter, Represents the actual value of the reactive power output by the power electronic converter, Represents the effective value of the rated voltage, Is the reactive voltage conversion coefficient, Represents the reference value corresponding to the three-phase positive-sequence voltage output by the power electronic converter, Represents the actual value of the three-phase positive-sequence voltage output by the power electronic converter.

[0081] Step 104: Determine the three-phase virtual internal potential according to the synchronous phase angle and the amplitude of the virtual internal potential. Refer to Figure 2 , in one implementation, step 104 may include:

[0082] Determine the three-phase virtual internal potential according to the synchronous phase angle and the amplitude of the virtual internal potential through the following formula;

[0083]

[0084] Wherein, Represents the synchronous phase angle, Represents the amplitude of the virtual internal potential, , And Represents the three-phase virtual internal potential.

[0085] In this embodiment, the three-phase potential refers to the potential generated by a power supply composed of three AC potentials with the same frequency, equal amplitude, and phases that are 120° out of phase with each other in sequence (the potential in the virtual synchronous machine in this application).

[0086] Step 105: Modify the three-phase virtual internal potential through the switching virtual impedance algorithm to obtain the target three-phase virtual internal potential, and determine the three-phase voltage regulation command for the AC voltage output by the power electronic converter according to the target three-phase virtual internal potential.

[0087] Specifically, step 105 may include:

[0088] If the change amplitude of the instantaneous value of the system voltage of the power system is greater than the preset voltage difference threshold, or the instantaneous value of the three-phase current output by the power electronic converter is greater than the preset current threshold, determine the additional voltage increment value corresponding to each phase of the internal potential in the three-phase virtual internal potential according to the virtual resistance, virtual reactance in the grid-forming control method, and the three-phase current output by the power electronic converter. The additional voltage increment value is used to correct the three-phase virtual internal potential;

[0089] Determine the sum value of each phase of the internal potential in the three-phase virtual internal potential and the corresponding additional voltage increment value to obtain the target three-phase virtual internal potential;

[0090] Modulate the target three-phase virtual internal potential through pulse width modulation technology to obtain the three-phase voltage regulation command.

[0091] Among them, Pulse Width Modulation (PWM) technology refers to the technology of simulating or adjusting the value of an analog signal by changing the duty cycle of a pulse signal (i.e., the ratio of the pulse width to the pulse period). The basic idea of pulse width modulation technology is to convert the required analog signal into a series of pulse signals, the widths of these pulse signals change with the magnitude of the analog signal, but their frequencies remain unchanged. Specific information about pulse width modulation technology can be referred to the description in the existing technology.

[0092] Among them, determining the additional voltage increment value corresponding to each phase potential in the three-phase virtual internal potential according to the virtual resistance, virtual reactance in the grid-forming control method, and the three-phase current output by the power electronic converter may include:

[0093] For each phase internal potential in the three-phase virtual internal potential, according to the virtual resistance, virtual reactance, and the three-phase current output by the power electronic converter, determine the corresponding additional voltage increment value through the following formula;

[0094]

[0095] Among them, represents the additional voltage increment value, represents the virtual resistance, represents the virtual reactance, represents the three-phase current output by the power electronic converter, represents the time constant, and s represents the Laplace differential operator.

[0096] In this application, the control strategy of the grid-forming control device also includes emergency current limiting control measures, as shown in Figure 2 . In specific implementation, once it is detected that the change amplitude ΔU (usually the decrease amplitude) of the instantaneous value of the system voltage of the power system is greater than the preset voltage difference threshold ΔU th , or the instantaneous value of the three-phase current output by the power electronic converter is greater than the preset current threshold I max , immediately take emergency current limiting control measures. When it is detected that the change amplitude ΔU of the instantaneous value of the system voltage is less than or equal to the set threshold ΔU th -U zone (U zone is set according to actual needs), or the instantaneous value of the three-phase current is less than or equal to the preset current threshold I max , exit the emergency current limiting control measures.

[0097] In this embodiment, the virtual resistance is mainly used to limit the peak value of the transient current and accelerate the transient transition process. The virtual resistance Mainly adopt the fast injection and slow withdrawal control strategy, that is, only at the moment of implementing the emergency current limiting measure it takes effect and maintains for a period of time , and then withdraws smoothly according to a certain slope. The control logic of the virtual resistance is as follows:

[0098]

[0099] In the above formula, the behind the equal sign represents the virtual resistance at the current moment, and the in front of the equal sign represents the expected virtual resistance at the next moment.

[0100] The specific value of the virtual resistance is determined by the following formula:

[0101]

[0102] Among them, is the virtual time constant, is the per-unit value of the arm reactance. The virtual time constant is usually selected as 10 - 20ms.

[0103] The specific value of the virtual reactance is determined by the following formula:

[0104]

[0105] Among them, is the preset current threshold corresponding to the instantaneous value of the three-phase current output by the power electronic converter, is the set value of the three-phase positive-sequence voltage.

[0106] During the emergency current limiting control process, the amplitude E of the virtual internal potential is selected to lock the amplitude of the virtual synchronous machine internal potential at 1.0 pu, ensuring that the grid-forming control device has the characteristics of an ideal voltage source during the fault. When the fault is restored, it has the transient overvoltage suppression characteristic to avoid unnecessary mode switching causing system instability.

[0107] Among them, the change amplitude ΔU of the system voltage instantaneous value is determined by the following formula:

[0108]

[0109] Among them, represents axis positive-sequence voltage, represents axis positive-sequence voltage.

[0110] The additional voltage increment values corresponding to the internal potentials of each phase in the three-phase virtual internal potential include 、 and 。

[0111]

[0112]

[0113]

[0114] Among them, the three-phase current output by the power electronic converter includes 、 and 。

[0115] After determining 、 、 、 、 、 、 the target three-phase virtual internal electromotive force is determined by the following formula:

[0116]

[0117] Then, the target three-phase virtual internal electromotive force is modulated by pulse width modulation technology to obtain a three-phase voltage regulation command. After the power electronic converter executes the three-phase voltage regulation command, it outputs an AC voltage according to 、 、 。

[0118] In this embodiment, if no emergency current limiting measure is taken, the target three-phase virtual internal electromotive force is as follows:

[0119]

[0120] In this embodiment, a short-circuit fault is detected within 5 ms after a fault occurs in the power electronic converter, and a virtual impedance link is put into operation for current limiting to ensure that the power electronic converter does not overcurrent instantaneously during the fault, and a maximum reactive current is output within 10 ms after the short-circuit fault occurs to support the power grid and ensure the stable operation of the power grid.

[0121] Step 106: Send a three-phase voltage regulation command to the power electronic converter to make the power electronic converter execute the three-phase voltage regulation command to adjust the output AC voltage.

[0122] In this embodiment, the three-phase voltage regulation instruction is essentially a switching instruction. After receiving the three-phase voltage regulation instruction, the power electronic converter in the new energy power station executes the three-phase voltage regulation instruction, adjusts the output AC voltage, and transmits the adjusted AC voltage to the power grid, which helps to maintain the stable operation of the power grid. Through the regulation of the power electronic converter, the compatibility and stability between new energy power generation and the power grid can be ensured.

[0123] This application constructs a grid-forming SVG control algorithm with pure voltage source characteristics. During the normal steady-state operation of the power electronic converter, the grid-forming SVG control method operates using the VSG single-loop control strategy. The control structure is simple, without complex parameter design, and abandons the traditional current inner loop, which maximally ensures the voltage source characteristics (the ability to stably provide a constant voltage) of the grid-forming SVG and has a strong reactive power support ability (the ability to provide or absorb reactive power to the grid), effectively solving the problems existing in the prior art.

[0124] The grid-forming SVG control method with pure voltage source characteristics in this application can be applied to various types of power electronic converter topologies, that is Figure 2 the topologies of the main circuit include but are not limited to three-level topologies and high-voltage cascade topologies. This application combines the intrinsic self-synchronizing grid-forming control technology based on capacitor direct voltage, virtual impedance technology, and virtual impedance switching logic, abandons the traditional current inner loop, and maximally ensures the voltage source characteristics of the grid-forming control device, enabling the grid-forming control device to release its support capabilities in terms of voltage and frequency to the greatest extent without overcurrent.

[0125] Due to the passive characteristics of the grid-forming SVG, this application adds a control link for the DC voltage at the input end of the power electronic converter to the synchronization loop. Through this control link, an active power instruction is generated and connected to the traditional VSG control link to achieve synchronization control based on capacitor voltage, and a VSG control outer loop is formed in combination with the reactive power excitation link.

[0126] To ensure that the grid-forming SVG converter does not overcurrent, this application adds a switchable virtual impedance control algorithm. When the power electronic converter operates stably, ensure the operation of a single VSG control loop; in the case of high-voltage and low-voltage faults in the system (power electronic converter), quickly detect the system fault and activate the current-limiting virtual impedance control link. Instantaneously increase the virtual inductance and transient virtual resistance during the fault to accelerate the transient transition process and reduce the transient current amplitude; subsequently, during the high and low voltage ride-through periods, the transient virtual resistance flexibly exits, and the virtual inductance is activated for steady-state current limiting; after the high and low voltage ride-through fault is restored, the virtual inductance exits, and the grid-forming control device returns to the stable operation state.

[0127] In summary, the present application generally adopts a network-forming SVG control strategy to regulate the output voltage of a power electronic converter. First, the power electronic converter determines the synchronous phase angle of the internal electromotive force of the virtual synchronous machine according to the actual value of the DC voltage at the input end of the power electronic converter and the reference value corresponding to the DC voltage, and determines the amplitude of the internal electromotive force of the virtual synchronous machine according to the reactive power output by the power electronic converter or the expected value of the system voltage amplitude of the power system. Then, according to the synchronous phase angle and the amplitude of the electromotive force, three-phase voltage modulation commands for the AC voltage output by the power electronic converter are determined. At the same time, to prevent the transient overcurrent of the network-forming equipment, the virtual impedance link is switched on and off in real time according to the voltage change and the current amplitude. The virtual impedance link generates an increment of the three-phase AC voltage modulation command after the measured current passes through the virtual resistance and virtual inductance links, and is superimposed on the three-phase voltage modulation command and then output after being put into operation. Finally, a three-phase voltage regulation command is sent to the power electronic converter, so that the power electronic converter executes the three-phase voltage regulation command to adjust the output AC voltage. The present application constructs a network-forming SVG control algorithm with a pure voltage source characteristic. During the normal steady-state operation of the power electronic converter, the network-forming SVG operates with a VSG single-loop control strategy. During the fault transient operation process, current limiting control is performed through the flexible switching of the virtual impedance. The control structure is simple, without complex parameter design, and the traditional current inner loop is abandoned, which maximally ensures the voltage source characteristic (the ability to stably provide a constant voltage) of the network-forming SVG, has a strong reactive power support ability (the ability to provide or absorb reactive power to the power grid), and has no high-frequency resonance risk in the full frequency band range, and can effectively solve the problems existing in the prior art.

[0128] Next, a network-forming control device provided by the present application will be described. The network-forming control device described below can be correspondingly referred to the network-forming control method described above.

[0129] The network-forming control device of the present application is used to regulate the output voltage of a power electronic converter, and the power electronic converter is used to convert the input DC voltage into an AC voltage and input it into the power grid.

[0130] Figure 3 It is a structural block diagram of a network-forming control device shown in an embodiment of the present application. Refer to Figure 3 , the network-forming control device 300 of the present application may include:

[0131] A generation module 301, configured to generate a virtual internal electromotive force for regulating the output voltage of the power electronic converter through an intrinsic self-synchronizing network-forming control technology based on capacitor direct voltage under a network-forming static var compensation strategy;

[0132] The first determination module 302 is configured to determine the synchronous phase angle of the virtual internal potential according to the actual value of the DC voltage at the input end of the power electronic converter and the reference value corresponding to the DC voltage, where the synchronous phase angle is used to adjust the phase of the AC voltage output by the power electronic converter;

[0133] The second determination module 303 is configured to determine the amplitude of the virtual internal potential according to the reactive power output by the power electronic converter or the system voltage amplitude of the power system;

[0134] The third determination module 304 is configured to determine the three-phase virtual internal potential according to the synchronous phase angle and the amplitude of the virtual internal potential;

[0135] The fourth determination module 305 is configured to correct the three-phase virtual internal potential through a switched virtual impedance algorithm to obtain a target three-phase virtual internal potential, and determine a three-phase voltage regulation command for the AC voltage output by the power electronic converter according to the target three-phase virtual internal potential;

[0136] The sending module 306 is configured to send the three-phase voltage regulation command to the power electronic converter, so that the power electronic converter executes the three-phase voltage regulation command to adjust the output AC voltage.

[0137] According to a network-forming control device 300 provided by the present application, the first determination module 302 includes:

[0138] The first determination sub-module is configured to determine the synchronous phase angle of the virtual internal potential through the following formula (1):

[0139] (1)

[0140] where represents the synchronous phase angle, represents the angular velocity of the virtual synchronous machine, J represents the inertia time constant, D represents the damping coefficient, K DW represents the angular velocity proportionality coefficient of the virtual synchronous machine, represents the control proportionality coefficient of the DC voltage at the input end of the power electronic converter, V dc-ref represents the reference value of the DC voltage at the input end of the power electronic converter, V dc-AVG represents the actual value of the DC voltage at the input end of the power electronic converter, represents the active power output by the power electronic converter, represents the frequency reference value, s represents the Laplace differential operator.

[0141] According to a network-forming control device 300 provided by the present application, the control proportionality coefficient of the DC voltage at the input end of the power electronic converter is determined by the following formula (2):

[0142] (2)

[0143] wherein, represents the set value of the control proportionality coefficient of the DC voltage at the input end of the power electronic converter, represents the difference between and represents the threshold value corresponding to the angular velocity of the virtual synchronous machine, represents the difference between and represents the change amplitude of the DC voltage at the input end of the power electronic converter, represents the threshold value corresponding to the change amplitude of the DC voltage at the input end of the power electronic converter.

[0144] According to a network-forming control device 300 provided by the present application, the fourth determination module 305 includes:

[0145] A second determination sub-module, configured to, if the change amplitude of the instantaneous value of the system voltage of the power system is greater than a preset voltage difference threshold, or the instantaneous value of the three-phase current output by the power electronic converter is greater than a preset current threshold, determine, according to the virtual resistance, virtual reactance in the network-forming control method, and the three-phase current output by the power electronic converter, an additional voltage increment value corresponding to each phase of the internal potential in the three-phase virtual internal potential, where the additional voltage increment value is used to correct the three-phase virtual internal potential;

[0146] A third determination sub-module, configured to determine the sum value of each phase of the internal potential in the three-phase virtual internal potential and the corresponding additional voltage increment value to obtain the target three-phase virtual internal potential;

[0147] A modulation sub-module, configured to modulate the target three-phase virtual internal potential through pulse width modulation technology to obtain the three-phase voltage regulation command.

[0148] According to a network-forming control device 300 provided by the present application, the second determination sub-module includes:

[0149] For each phase of the internal potential in the three-phase virtual internal potential, determine the corresponding additional voltage increment value according to the virtual resistance, the virtual reactance, and the three-phase current output by the power electronic converter through the following formula (3);

[0150] (3)

[0151] Wherein, represents the additional voltage increment value, represents the virtual resistance, represents the virtual reactance, represents the three-phase current output by the power electronic converter, represents the time constant, and s represents the Laplace differential operator.

[0152] According to a grid-forming control device 300 provided by the present application, the second determination module 303 includes:

[0153] A fourth determination sub-module, configured to determine the amplitude of the virtual internal potential according to the actual value of the reactive power output by the power electronic converter and the reference value corresponding to the reactive power if the reactive power control mode is adopted in the excitation control link;

[0154] A fifth determination sub-module, configured to determine the amplitude of the virtual internal potential according to the actual value of the three-phase positive-sequence voltage output by the power system and the reference value corresponding to the three-phase positive-sequence voltage if the voltage control mode is adopted in the excitation control link.

[0155] According to a grid-forming control device 300 provided by the present application, the third determination module 304 includes:

[0156] A sixth determination sub-module, configured to determine the three-phase virtual internal potential according to the synchronous phase angle and the amplitude of the virtual internal potential through the following formula (4):

[0157] (4)

[0158] Wherein, represents the synchronous phase angle, represents the amplitude of the virtual internal potential, 、 and represent the three-phase virtual internal potential. Figure 4 is a schematic physical structure diagram of an electronic device shown in an embodiment of the present application. As Figure 4 shown, the electronic device may include: a processor 410, a communication interface 420, a memory 430, and a communication bus 440. Among them, the processor 410, the communication interface 420, and the memory 430 complete mutual communication through the communication bus 440. The processor 410 can call the logical instructions in the memory 430 to execute a grid-forming control method, and the method includes:

[0159] Under the grid-forming static var compensation strategy, a virtual internal electromotive force for regulating the output voltage of the power electronic converter is generated through the intrinsic self-synchronizing grid-forming control technology based on the direct voltage of the capacitor.

[0160] According to the actual value of the DC voltage at the input end of the power electronic converter and the reference value corresponding to the DC voltage, the synchronization phase angle of the virtual internal electromotive force is determined, and the synchronization phase angle is used to regulate the phase of the AC voltage output by the power electronic converter.

[0161] According to the reactive power output by the power electronic converter or the system voltage amplitude of the power system, the amplitude of the virtual internal electromotive force is determined.

[0162] According to the synchronization phase angle and the amplitude of the virtual internal electromotive force, a three-phase virtual internal electromotive force is determined.

[0163] The three-phase virtual internal electromotive force is corrected through a switched virtual impedance algorithm to obtain a target three-phase virtual internal electromotive force, and a three-phase voltage regulation command for the AC voltage output by the power electronic converter is determined according to the target three-phase virtual internal electromotive force.

[0164] The three-phase voltage regulation command is sent to the power electronic converter, and the power electronic converter executes the three-phase voltage regulation command to adjust the output AC voltage.

[0165] In addition, when the logical instructions in the above-mentioned memory 430 are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present application essentially or the part that contributes to the prior art or a part of this technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present application. The foregoing storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs that can store program codes.

[0166] On the other hand, the present application also provides a computer program product. The computer program product includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute a grid-forming control method provided by the above-mentioned various methods. The method includes:

[0167] Under the grid-forming static var compensation strategy, a virtual internal electromotive force for regulating the output voltage of the power electronic converter is generated through the intrinsic self-synchronizing grid-forming control technology based on the capacitor direct voltage;

[0168] According to the actual value of the DC voltage at the input end of the power electronic converter and the reference value corresponding to the DC voltage, the synchronization phase angle of the virtual internal electromotive force is determined, and the synchronization phase angle is used to regulate the phase of the AC voltage output by the power electronic converter;

[0169] According to the reactive power output by the power electronic converter or the system voltage amplitude of the power system, the amplitude of the virtual internal electromotive force is determined;

[0170] According to the synchronization phase angle and the amplitude of the virtual internal electromotive force, a three-phase virtual internal electromotive force is determined;

[0171] Through the switching virtual impedance algorithm, the three-phase virtual internal electromotive force is corrected to obtain a target three-phase virtual internal electromotive force, and a three-phase voltage regulation command for the AC voltage output by the power electronic converter is determined according to the target three-phase virtual internal electromotive force;

[0172] The three-phase voltage regulation command is sent to the power electronic converter, so that the power electronic converter executes the three-phase voltage regulation command to adjust the output AC voltage.

[0173] On the other hand, the present application also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, a grid-forming control method provided by the above-mentioned various methods is implemented. The method includes:

[0174] Under the grid-forming static var compensation strategy, a virtual internal electromotive force for regulating the output voltage of the power electronic converter is generated through the intrinsic self-synchronizing grid-forming control technology based on the capacitor direct voltage;

[0175] According to the actual value of the DC voltage at the input end of the power electronic converter and the reference value corresponding to the DC voltage, the synchronization phase angle of the virtual internal electromotive force is determined, and the synchronization phase angle is used to regulate the phase of the AC voltage output by the power electronic converter;

[0176] According to the reactive power output by the power electronic converter or the system voltage amplitude of the power system, the amplitude of the virtual internal electromotive force is determined;

[0177] According to the synchronization phase angle and the amplitude of the virtual internal electromotive force, a three-phase virtual internal electromotive force is determined;

[0178] The three-phase virtual internal electromotive force is corrected by a switching virtual impedance algorithm to obtain a target three-phase virtual internal electromotive force, and a three-phase voltage regulation command for the AC voltage output by the power electronic converter is determined according to the target three-phase virtual internal electromotive force;

[0179] The three-phase voltage regulation command is sent to the power electronic converter, so that the power electronic converter executes the three-phase voltage regulation command to adjust the output AC voltage. The device embodiments described above are merely illustrative, where the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative efforts.

[0180] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution, in essence, or the part that contributes to the prior art can be embodied in the form of a software product, which can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., including several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0181] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of each embodiment of the present application.

Claims

1. A network control method, characterized in that: The method is used to adjust the output voltage of the power electronic converter, wherein the power electronic converter is used to convert the input DC voltage into AC voltage and input it into the power system. The network control method includes: Under the grid-forming static VAR compensation strategy, a virtual internal potential for adjusting the output voltage of the power electronic converter is generated by an intrinsic self-synchronous grid-forming control technology based on capacitor direct pressure; Determining a synchronous phase angle of the virtual internal potential according to an actual value of a DC voltage at an input end of the power electronic converter and a reference value corresponding to the DC voltage, wherein the synchronous phase angle is used to adjust a phase of an AC voltage output by the power electronic converter; Determining the amplitude of the virtual internal potential according to the reactive power output by the power electronic converter or the voltage amplitude of the power system; Determining a three-phase virtual internal potential according to the synchronization phase angle and the amplitude of the virtual internal potential; By switching a virtual impedance algorithm, the three-phase virtual internal potential is corrected to obtain a target three-phase virtual internal potential, and a three-phase voltage regulation instruction for the AC voltage output by the power electronic converter is determined according to the target three-phase virtual internal potential; Sending the three-phase voltage regulation instruction to the power electronic converter, so that the power electronic converter executes the three-phase voltage regulation instruction to adjust the output AC voltage; Wherein, determining the synchronization phase angle of the virtual internal potential according to the actual value of the DC voltage at the input end of the power electronic converter and the reference value corresponding to the DC voltage includes: The synchronous phase angle of the virtual internal potential is determined by the following formula (1): （1） in, represents the synchronization phase angle, represents the angular velocity of the virtual synchronous machine, J represents the inertia time constant, D represents the damping coefficient, K DW represents the angular velocity proportionality coefficient of the virtual synchronous machine, K v Represents the control proportional coefficient of the DC voltage at the input of the power electronic converter, V dc-ref The reference value of the DC voltage at the input of the power electronic converter, V dc-AVG represents the actual value of the DC voltage at the input of the power electronic converter, Represents the active power output by the power electronic converter, represents the frequency reference value, s represents the Laplace differential operator, is the integral symbol; The method of correcting the three-phase virtual internal potential by switching the virtual impedance algorithm to obtain the target three-phase virtual internal potential includes: If the change amplitude of the instantaneous value of the system voltage of the power system is greater than the preset voltage difference threshold, or the instantaneous value of the three-phase current output by the power electronic converter is greater than the preset current threshold, the corresponding additional voltage increment value is determined by the following formula (3) according to the virtual resistance, virtual reactance and the three-phase current output by the power electronic converter in the network control method, and the sum of the internal potential of each phase in the three-phase virtual internal potential and the corresponding additional voltage increment value is determined to obtain the target three-phase virtual internal potential, and the additional voltage increment value is used to correct the three-phase virtual internal potential; （3） in, Indicates the additional voltage increment value, represents the virtual resistance, represents the virtual reactance, Represents the three-phase current output by the power electronic converter, represents the time constant, and s represents the Laplace differential operator.

2. The network control method according to claim 1, characterized in that: The control proportional coefficient of the DC voltage at the input end of the power electronic converter is determined by the following formula (2): （2） in, Indicates the set value of the control proportional coefficient of the DC voltage at the input end of the power electronic converter, express and The difference, Indicates the threshold value corresponding to the angular velocity of the virtual synchronous machine, express and The threshold value corresponding to the difference between Indicates the variation of the DC voltage at the input of the power electronic converter. Indicates the threshold corresponding to the change amplitude of the DC voltage at the input end of the power electronic converter.

3. The network control method according to claim 1, characterized in that: The step of determining a three-phase voltage regulation instruction for an AC voltage output by the power electronic converter according to the target three-phase virtual internal potential comprises: The target three-phase virtual internal potential is modulated by pulse width modulation technology to obtain the three-phase voltage regulation instruction.

4. The network control method according to claim 1, characterized in that: The excitation control link of the grid control method supports a reactive control mode and a voltage control mode, and the AC voltage output by the power system is a three-phase positive sequence voltage; the amplitude of the virtual internal potential is determined according to the reactive power output by the power electronic converter or the voltage amplitude of the power system, including: If the reactive power control mode is adopted in the excitation control link, the amplitude of the virtual internal potential is determined according to the actual value of the reactive power output by the power electronic converter and the reference value corresponding to the reactive power; If the voltage control mode is adopted in the excitation control link, the amplitude of the virtual internal potential is determined according to the actual value of the three-phase positive-sequence voltage output by the power system and the reference value corresponding to the three-phase positive-sequence voltage.

5. The network control method according to claim 1, characterized in that: Determining the three-phase virtual internal potential according to the synchronization phase angle and the amplitude of the virtual internal potential includes: The three-phase virtual internal potential is determined according to the synchronous phase angle and the amplitude of the virtual internal potential by the following formula (4): （4） in, represents the synchronization phase angle, represents the magnitude of the virtual internal potential, , as well as Represents the three-phase virtual internal potential.

6. A network control device, characterized in that: Used to adjust the output voltage of the power electronic converter, the power electronic converter is used to convert the input DC voltage into AC voltage and input it into the power system, the network control device includes: A generation module, used for generating a virtual internal potential for adjusting the output voltage of the power electronic converter by using an intrinsic self-synchronous grid control technology based on capacitor direct pressure under a grid-forming static VAR compensation strategy; A first determination module, configured to determine a synchronization phase angle of the virtual internal potential according to an actual value of a DC voltage at an input end of the power electronic converter and a reference value corresponding to the DC voltage, wherein the synchronization phase angle is used to adjust a phase of an AC voltage output by the power electronic converter; A second determination module is used to determine the amplitude of the virtual internal potential according to the reactive power output by the power electronic converter or the voltage amplitude of the power system; a third determination module, configured to determine a three-phase virtual internal potential according to the synchronization phase angle and the amplitude of the virtual internal potential; a fourth determination module, configured to correct the three-phase virtual internal potential by switching a virtual impedance algorithm to obtain a target three-phase virtual internal potential, and determine a three-phase voltage regulation instruction for the AC voltage output by the power electronic converter according to the target three-phase virtual internal potential; A sending module, used for sending the three-phase voltage adjustment instruction to the power electronic converter, so that the power electronic converter executes the three-phase voltage adjustment instruction to adjust the output AC voltage; The first determination module includes a first determination submodule, and the first determination submodule is used to determine the synchronization phase angle of the virtual internal potential by the following formula (1): （1） in, represents the synchronization phase angle, represents the angular velocity of the virtual synchronous machine, J represents the inertia time constant, D represents the damping coefficient, K DW represents the angular velocity proportionality coefficient of the virtual synchronous machine, K v Represents the control proportional coefficient of the DC voltage at the input of the power electronic converter, V dc-ref The reference value of the DC voltage at the input of the power electronic converter, V dc-AVG represents the actual value of the DC voltage at the input of the power electronic converter, Represents the active power output by the power electronic converter, represents the frequency reference value, s represents the Laplace differential operator; The fourth determination module includes a second determination submodule and a third determination submodule. The second determination submodule is used to determine the corresponding additional voltage increment value by the following formula (3) according to the virtual resistance, virtual reactance and the three-phase current output by the power electronic converter in the network control method if the change amplitude of the instantaneous value of the system voltage of the power system is greater than the preset voltage difference threshold, or the instantaneous value of the three-phase current output by the power electronic converter is greater than the preset current threshold. The third determination submodule is used to determine the sum of the internal potential of each phase in the three-phase virtual internal potential and the corresponding additional voltage increment value to obtain the target three-phase virtual internal potential. The additional voltage increment value is used to correct the three-phase virtual internal potential. （3） in, Indicates the additional voltage increment value, represents the virtual resistance, represents the virtual reactance, Represents the three-phase current output by the power electronic converter, represents the time constant, and s represents the Laplace differential operator.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the network control method as described in any one of claims 1 to 5 is implemented.

8. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, a networking control method as described in any one of claims 1 to 5 is implemented.

9. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, a networking control method as described in any one of claims 1 to 5 is implemented.

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