A method and system for controlling an energy storage converter based on network- to-grid coupling

Abstract

The application discloses a kind of based on network-construction coupling energy storage converter control method and system, the method includes: extracting and processing the output current of energy storage converter and comparing with reference current to obtain comparison signal;Comparison signal is input to network construction type control branch to obtain first reference voltage;Comparison signal is input to follow network type control branch to obtain second reference voltage;First reference voltage and second reference voltage are input to network-construction coupling model to obtain coupling voltage;Based on coupling voltage control energy storage converter.The system corresponds to the method.This application, by the coupling of network construction type control branch and follow network type control branch, both have the support ability of network control to grid voltage, frequency, and can realize fast current response by follow network control, effectively improve the dynamic performance and grid adaptability of energy storage converter.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power electronic control, and in particular to a control method and system of energy storage converter based on network construction-network following coupling. BACKGROUND

[0002] At present, the mainstream network construction type control strategy, such as virtual synchronous generator VSG, has certain voltage support ability, but its dynamic response speed is difficult to meet the actual fast power regulation requirement due to the limitation of control structure and parameter setting; while the traditional network following type control strategy, such as PQ control, has good dynamic response, but lacks independent voltage regulation ability, and is difficult to operate stably in grid fault or weak grid environment.

[0003] The Chinese invention patent application with the application publication number CN118739442A discloses a network following type and network construction type converter fusion control method, which helps to improve the stable operation and anti-interference ability of the converter in the new energy high penetration rate scene, but it does not propose an effective solution to the balance between network construction ability and fast response performance.

[0004] Therefore, there is an urgent need for a new type of energy storage converter control technical solution that can balance network construction ability and fast response performance, in order to improve the stability and safety of new energy power system. SUMMARY

[0005] The main purpose of the present application is to provide a control method and system of energy storage converter based on network construction-network following coupling, which aims to solve the technical problems of insufficient voltage support ability and power response delay existing in single network construction type control and network following type control in the prior art.

[0006] To achieve the above-mentioned purpose, the present application provides a control method of energy storage converter based on network construction-network following coupling, which comprises the following steps:

[0007] Step one: extracting and processing the output current of the energy storage converter, comparing the output current with the reference current to obtain a comparison signal, and the reference current is obtained based on the reference power;

[0008] Step two: inputting the comparison signal into the pre-constructed network construction type control branch to obtain a first reference voltage, and the network construction type control branch is used to provide voltage support;

[0009] Step three: inputting the comparison signal into the pre-constructed network following type control branch to obtain a second reference voltage, and the network following type control branch is used to provide current response;

[0010] Step four: inputting the first reference voltage and the second reference voltage into a pre-constructed grid-following coupling model to obtain a coupling voltage, the grid-following coupling model being used to superimpose the first reference voltage and the second reference voltage;

[0011] Step five: controlling the energy storage converter based on the coupling voltage.

[0012] As preferred, the step one comprises:

[0013] A1: extracting the output current from the inverter of the energy storage converter and performing coordinate transformation on the output current;

[0014] A2: subtracting the output current after the coordinate transformation from the reference current, and defining the obtained difference as the comparison signal

[0015] As preferred, the step two comprises:

[0016] B1: constructing the grid-forming control branch, the grid-forming control branch being a grid-forming virtual oscillator control structure, which at least comprises a virtual capacitor and a virtual inductor;

[0017] B2: inputting the comparison signal into the grid-forming virtual oscillator control structure, and outputting and defining a virtual capacitor voltage and a virtual inductor current as the first reference voltage.

[0018] As preferred, the first reference voltage is represented as , and the control equation of the grid-forming virtual oscillator control structure is:

[0019]

[0020] wherein, is a grid-forming axis voltage output, is a grid-forming axis voltage output, is an effective value of inverter output phase voltage, is an inverter output frequency reference, is a scaling coefficient of input current, is a scaling coefficient of output voltage, is the virtual capacitor, is a control parameter for controlling the speed of voltage convergence, is a defined rotation angle, is a axis current input, is a axis current input.

[0021] As preferred, the step three comprises:

[0022] C1: constructing the grid-following control branch, the grid-following control branch comprising a grid-following current control unit and a coupling unit;

[0023] C2: inputting the comparison signal into the grid-following control branch, outputting after the coupling unit and defining as the second reference voltage.

[0024] As preferred, the grid-following current control unit is controlled by a grid-following current control equation, the grid-following current control equation being:

[0025]

[0026] wherein, is a grid-following axis voltage output, is a grid-following axis voltage output, is axis current input, is axis current input, is a coupling coefficient.

[0027] As preferred, the coupling unit is provided with a coupling coefficient, and the coupling coefficient is obtained based on a dynamic response time constant, the dynamic response time constant being determined based on a dynamic response time constant formula, the dynamic response time constant formula being:

[0028]

[0029] wherein, is the determined dynamic response time constant, is the coupling coefficient, is a grid-side impedance, and the coupling coefficient is larger, the dynamic response time constant is smaller, and the response speed of the energy storage converter is faster, a reference value of active power.

[0030] As preferred, the step four comprises:

[0031] D1: constructing the grid-following-network coupling model, the grid-following-network coupling model taking the first reference voltage and the second reference voltage as input, and taking a result after superimposing the first reference voltage and the second reference voltage as output; wherein the superimposition of the first reference voltage and the second reference voltage is performed by a grid-following-network coupling control equation, the grid-following-network coupling control equation being:

[0032]

[0033] wherein, is the result of the superposition of the first reference voltage and the second reference voltage, is the output of the grid-forming control branch, is the output of the grid-following control branch;

[0034] D2: inputting the first reference voltage and the second reference voltage into the grid-forming-grid-following coupling model, outputting and defining as the coupling voltage.

[0035] As preferred, when the energy storage inverter is in inductive grid conditions, the method further comprises the following steps:

[0036] E1: setting the rotation angle as so that the inverter presents a droop characteristic of active power and grid frequency and a droop characteristic of reactive power and grid voltage amplitude;

[0037] E2: increasing the coupling coefficient so that the dynamic response time constant is reduced, and the response time of active power is reduced;

[0038] When the energy storage inverter has a grid frequency dip and / or a voltage dip, the method further comprises the following steps:

[0039] F1: maintaining the output voltage and frequency through the self-synchronization characteristic of the grid-forming control branch;

[0040] F2: quickly compensating for current error through the current control of the grid-following control branch.

[0041] To achieve the above object, the application further provides an energy storage inverter control system based on grid-forming-grid-following coupling, which applies the energy storage inverter control method based on grid-forming-grid-following coupling as described above, and the system comprises:

[0042] a current comparison module for extracting and processing the output current of the energy storage inverter, comparing the output current with a reference current to obtain a comparison signal, the reference current being obtained based on a reference power;

[0043] a grid-forming control module for inputting the comparison signal into a pre-constructed grid-forming control branch to obtain a first reference voltage, the grid-forming control branch being used for providing voltage support;

[0044] a grid-following control module for inputting the comparison signal into a pre-constructed grid-following control branch to obtain a second reference voltage, the grid-following control branch being used for providing current response;

[0045] a network-construction and network-following coupling module, configured to input the first reference voltage and the second reference voltage into a pre-constructed network-construction and network-following coupling model to obtain a coupling voltage, the network-construction and network-following coupling model being configured to superimpose the first reference voltage and the second reference voltage;

[0046] a control execution module, configured to control the energy storage converter based on the coupling voltage.

[0047] Beneficial effects: The energy storage converter control method and system based on network-construction and network-following coupling provided by the application can couple a network-construction type control branch and a network-following type control branch, rely on the network-construction type control to simulate the characteristics of a synchronous machine to provide voltage, frequency support and inertia for the power grid, and rely on the network-following type control to achieve fast current response; meanwhile, the coupling coefficient, rotation angle and other parameters are dynamically optimized in combination with the characteristics of the power grid, so that the active power response time can be significantly shortened and the dynamic adjustment speed can be improved while ensuring the stability of the power grid, effectively solving the problem that the traditional energy storage converter is difficult to balance the power grid support capability and fast response performance, and enhancing the adaptability of the energy storage system to different power grid scenarios. BRIEF DESCRIPTION OF DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows. Obviously, for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0049] Figure 1 a flow chart of the energy storage converter control method based on network-construction and network-following coupling provided by the embodiment of the application;

[0050] Figure 2 a schematic diagram of the energy storage converter control method based on network-construction and network-following coupling provided by the embodiment of the application;

[0051] Figure 3 a dynamic active power response waveform diagram of a traditional network-construction type controlled energy storage converter which does not use the energy storage converter control method based on network-construction and network-following coupling provided by the embodiment of the application;

[0052] Figure 4 a dynamic active power response waveform diagram of an energy storage converter which uses the energy storage converter control method based on network-construction and network-following coupling provided by the embodiment of the application;

[0053] Figure 5 a waveform diagram of an energy storage converter responding to a power grid frequency dip which uses the energy storage converter control method based on network-construction and network-following coupling provided by the embodiment of the application;

[0054] Figure 6A waveform diagram of a power storage converter coping with grid voltage sag using a power storage converter control method based on network construction-following network coupling is provided for an embodiment of the present application.

[0055] Figure 7 A structure block diagram of a power storage converter control system based on network construction-following network coupling is provided for an embodiment of the present application.

[0056] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0057] It should be understood that the specific embodiments described herein are intended to be illustrative only and not limiting of the present application.

[0058] Embodiment One

[0059] To solve the technical problems of insufficient voltage support capability and power response delay existing in single network construction type control and network following type control, the present embodiment discloses a power storage converter control method based on network construction-following network coupling, which is applied to a power storage converter system, and specifically applied to a control circuit of the power storage converter system.

[0060] Reference Figure 1 , Figure 1 A flow block diagram of a power storage converter control method based on network construction-following network coupling is provided for the present embodiment.

[0061] As shown in Figure 1 , the present embodiment discloses a power storage converter control method based on network construction-following network coupling, which comprises the following steps:

[0062] Step one: extracting and processing the output current of the power storage converter, comparing the output current with the reference current to obtain a comparison signal, and the reference current is obtained based on the reference power.

[0063] Specifically, step one comprises:

[0064] A1: extracting the output current from the inverter of the power storage converter, and performing coordinate transformation on the output current.

[0065] In actual application, the present embodiment extracts the output current from the inverter , and performs coordinate transformation to .

[0066] A2: subtracting the reference current from the coordinate-transformed output current, and defining the difference value obtained as a comparison signal; wherein the reference current is determined based on a reference current calculation formula, and the reference current calculation formula is:

[0067]

[0068] wherein, is a reference value of active power, is a reference value of reactive power, is an inverter output voltage axis component, is an inverter output voltage axis component, is an inverter output voltage, is a reference current axis component, is a reference current axis component, the obtained reference current is expressed as .

[0069] In actual application, the output current is subtracted from the reference current to obtain a comparison signal.

[0070] Referring to Figure 2 , Figure 2 is a schematic diagram of a control method of an energy storage converter based on network-constructing and network-following coupling provided by the embodiment. In actual application, the energy storage converter system comprises a main power circuit and a control circuit. The main power circuit comprises a direct current voltage source, an inverter, an L-type filter and an infinite grid; the control circuit is the application object of the embodiment, which comprises a network-constructing controller, a network-following controller and a coupling controller.

[0071] Step two: inputting the comparison signal into a pre-constructed network-constructing control branch to obtain a first reference voltage, the network-constructing control branch being used to provide voltage support.

[0072] As shown in the figure, specifically, step two comprises: Figure 2

[0073] B1: constructing a network-constructing control branch, the network-constructing control branch being in a network-constructing virtual oscillator control structure, which at least comprises a virtual capacitor and a virtual inductor;

[0074] B2: inputting the comparison signal into the network-constructing virtual oscillator control structure, outputting the virtual capacitor voltage and the virtual inductor current and defining them as the first reference voltage.

[0075] Specifically, the first reference voltage is expressed as , and the control equation of the network-constructing virtual oscillator control structure is:

[0076]

[0077] wherein, is a network-constructing axis voltage output, is a network-constructing​ axis voltage output, for inverter output phase voltage effective value, for inverter output frequency reference, for input current scaling factor, for output voltage scaling factor, for virtual capacitance, for control parameter for controlling speed of voltage convergence, for defined rotation angle, axis current input, axis current input. It is to be noted that in the present embodiment, indicates network-constructing type axis voltage output first derivative, corresponding to, indicates network-constructing type axis voltage output first derivative. Thus, in the present embodiment, all indicate corresponding physical quantity first derivative.

[0078] Step three: input the comparison signal into the pre-constructed network-following type control branch to obtain a second reference voltage, the network-following type control branch being used to provide current response.

[0079] As Figure 2 shown, specifically, step three includes:

[0080] C1: constructing a network-following type control branch, the network-following type control branch including a network-following type current control unit and a coupling unit;

[0081] C2: inputting the comparison signal into the network-following type control branch, outputting after the coupling unit and defining as a second reference voltage.

[0082] Specifically, the network-following type current control unit is controlled by a network-following type current control equation, the network-following type current control equation being:

[0083]

[0084] wherein, is network-following type axis voltage output, is network-following type axis voltage output, is axis current input, is axis current input, is coupling coefficient.

[0085] Further, the network-following type current control further includes: ​​

[0086]

[0087] wherein, is a proportional gain, is a resonance gain, is a resonance frequency, is a cut-off frequency.

[0088] Specifically, the coupling unit is provided with a coupling coefficient, and the coupling coefficient is obtained based on a dynamic response time constant, the dynamic response time constant is determined based on a dynamic response time constant formula, and the dynamic response time constant formula is:

[0089]

[0090] wherein, is a determined dynamic response time constant, is a coupling coefficient, is a grid-side impedance, and the coupling coefficient is greater, the dynamic response time constant is smaller, the response speed of the energy storage converter is faster, a reference value of active power.

[0091] Step four: input the first reference voltage and the second reference voltage into the pre-constructed grid-following-coupling model to obtain a coupling voltage, and the grid-following-coupling model is used to superimpose the first reference voltage and the second reference voltage .

[0092] As Figure 2 shown, specifically, step four includes:

[0093] D1: constructing a grid-following-coupling model, the grid-following-coupling model taking the first reference voltage and the second reference voltage as input, and taking the result of superimposing the first reference voltage and the second reference voltage as output; wherein the superposition of the first reference voltage and the second reference voltage is performed through a grid-following-coupling control equation, and the grid-following-coupling control equation is:

[0094]

[0095] wherein, is a result of superimposing the first reference voltage and the second reference voltage, is an output of a grid-type control branch, is an output of a grid-following-type control branch;

[0096] D2: input the first reference voltage and the second reference voltage into the grid-following-coupling model, and output and define as a coupling voltage.

[0097] Based on steps one to four, in the specific application of the present embodiment, the network-construction and network-following coupled control equation is expanded as:

[0098]

[0099] Further, the network-following control branch can be equivalent to:

[0100]

[0101] The expression of the amplitude of the energy storage converter output voltage and the phase angle is given by:

[0102]

[0103]

[0104] Combined with the amplitude , the phase angle and the network-construction and network-following coupled control equation, the dynamic equation of the voltage amplitude and the phase angle can be obtained:

[0105]

[0106]

[0107] In actual applications, usually is 0, then the dynamic equation of the voltage amplitude and the phase angle is simplified as:

[0108]

[0109]

[0110] In an inductive network, the three-phase active power can be expressed as:

[0111]

[0112] wherein, and are the effective value and the phase angle of the grid voltage, is the grid-side impedance. Since is very small, there is . And the infinite grid has , if is set, then the first-order equation of the active power of the network-construction and network-following coupled control can be obtained:

[0113]

[0114] Taking the Laplace transform on both sides of the equation respectively can obtain:

[0115]

[0116] The dynamic response time constant can be obtained :

[0117]

[0118] Thus, we determine the coupling coefficient The larger the time constant The smaller the system response speed is faster.

[0119] Through the above steps, the fast current following network type control is coupled in the traditional network type control structure, realizing the cooperative operation of the network type control and the following network type control. Compared with the traditional network type control, the network-following coupling type control has faster active power dynamic response speed, and the system overshoot is significantly reduced, which embodies better dynamic response performance; compared with the following network type control, the network-following coupling type control has the advantages of the network type control, which embodies stronger fault ride-through capability and can cope with power grid voltage sag and other faults.

[0120] Referring to Figure 3 and Figure 4 , Figure 3 is a dynamic response waveform diagram of the active power of the energy storage converter using the traditional network type control method provided by the energy storage converter control method based on the network-following coupling provided by the present embodiment, Figure 4 is a dynamic response waveform diagram of the active power of the energy storage converter using the traditional network type control method provided by the energy storage converter control method based on the network-following coupling provided by the present embodiment.

[0121] As shown in Figure 3 and Figure 4 , as a preferred embodiment of the present embodiment, when the energy storage converter is in an inductive grid condition, the method further includes the following steps:

[0122] E1: set the rotation angle to , so that the inverter presents the droop characteristics of active power and grid frequency and the droop characteristics of reactive power and grid voltage amplitude;

[0123] E2: increase the coupling coefficient , so that the dynamic response time constant is reduced, and the response time of the active power is reduced.

[0124] Based on this, the active power response speed of the energy storage converter of the network-following coupling type control of the present embodiment is significantly faster than the active power response speed of the energy storage converter of the traditional network type control.

[0125] Referring to Figure 5 and Figure 6 ,Figure 5 A waveform diagram of the energy storage converter responding to the grid frequency sag using the energy storage converter control method based on the grid-keeping and grid-following coupling provided by the embodiment, Figure 6 A waveform diagram of the energy storage converter responding to the grid voltage sag using the energy storage converter control method based on the grid-keeping and grid-following coupling provided by the embodiment.

[0126] As shown in Figure 3 and Figure 4 , as a preferred embodiment of the embodiment, when the energy storage converter exists grid frequency sag and / or voltage sag, the method further comprises the following steps:

[0127] F1: maintaining the output voltage and frequency by the self-synchronization characteristics of the grid-keeping control branch;

[0128] F2: quickly compensating the current error by the current control of the grid-following control branch.

[0129] Based on this, the embodiment utilizes the self-synchronization characteristics of the grid-keeping control branch to maintain the stability of the output voltage and frequency, and utilizes the current control of the grid-following control branch to quickly compensate the current error and suppress the steady-state overshoot.

[0130] Step five: controlling the energy storage converter based on the coupling voltage.

[0131] In actual application, the output of the grid-keeping control branch and the output of the grid-keeping control branch are superimposed as , and after coordinate transformation, three-phase modulation waves are generated, and the switching tube of the energy storage converter is controlled by PWM modulation to realize the energy transmission of the energy storage converter.

[0132] Embodiment two

[0133] To achieve the above-mentioned purpose, refer to Figure 7 , Figure 7 The structural block diagram of the energy storage converter control system based on the grid-keeping and grid-following coupling provided by the embodiment.

[0134] As shown in Figure 7 , the embodiment discloses an energy storage converter control system based on the grid-keeping and grid-following coupling, which applies the energy storage converter control method based on the grid-keeping and grid-following coupling as described above, and the system comprises:

[0135] A current comparison module for extracting and processing the output current of the energy storage converter, comparing the output current with the reference current to obtain a comparison signal, and obtaining the reference current based on the reference power;

[0136] A grid-keeping control module for inputting the comparison signal into a pre-constructed grid-keeping control branch to obtain a first reference voltage, and the grid-keeping control branch is used to provide voltage support;

[0137] a grid-following control module, configured to input the comparison signal into a pre-constructed grid-following control branch to obtain a second reference voltage, the grid-following control branch being configured to provide a current response;

[0138] a grid-constructing and grid-following coupling module, configured to input the first reference voltage and the second reference voltage into a pre-constructed grid-constructing and grid-following coupling model to obtain a coupling voltage, the grid-constructing and grid-following coupling model being configured to superimpose the first reference voltage and the second reference voltage;

[0139] a control execution module, configured to control the energy storage converter based on the coupling voltage.

[0140] It should be noted that the energy storage converter control system based on grid-constructing and grid-following coupling in the embodiment corresponds to the energy storage converter control method based on grid-constructing and grid-following coupling described above. Therefore, the contents not specifically described in the energy storage converter control system based on grid-constructing and grid-following coupling in the embodiment can be, but are not limited to, functional definitions, working principles and technical effects, and can all refer to the descriptions in the energy storage converter control method based on grid-constructing and grid-following coupling described above, which will not be described herein.

[0141] In summary, the energy storage converter control method and system based on grid-constructing and grid-following coupling provided in the embodiment can rely on the grid-constructing control branch to simulate the characteristics of synchronous machines to provide voltage, frequency support and inertia for the power grid, and rely on the grid-following control branch to achieve fast current response. At the same time, the parameters such as coupling coefficient and rotation angle are dynamically optimized in combination with the characteristics of the power grid, which can ensure the stability of the power grid while significantly shortening the active power response time and improving the dynamic adjustment speed, effectively solving the problem that the traditional energy storage converter is difficult to balance the power grid support capability and fast response performance, and enhancing the adaptability of the energy storage system to different power grid scenarios.

[0142] It should be understood that the above is only for illustration, and does not constitute any limitation on the technical solutions of the present application. In specific applications, those skilled in the art can set it up according to the needs, and the present application does not limit it.

[0143] It should be noted that the above-described workflow is only illustrative and does not limit the scope of protection of the present application. In actual applications, those skilled in the art can select part or all of them to achieve the purpose of the embodiment scheme according to actual needs, which is not limited here.

[0144] It should be noted that, in the present document, the terms "comprising", "including", or any other variant thereof are intended to cover a non-exclusive inclusion, such that processes, methods, articles, or systems that comprise a list of elements not only include those elements, but also other elements not expressly listed, or other elements inherent to such processes, methods, articles, or systems. Without more limitations, an element defined by the phrase "comprising a" does not exclude the presence of additional identical elements in the process, method, article, or system that includes the element.

[0145] Through the above description of the embodiments, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be realized by means of software and the necessary general hardware platform, of course, they can also be realized by hardware, but in many cases the former is a better embodiment. Based on such understanding, the technical solutions of the present application can be embodied in the form of a software product, which is stored in a storage medium (such as a read-only memory / random access memory, a magnetic disk, an optical disk), and includes a number of instructions for making a terminal device (which can be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) execute the methods described in various embodiments of the present application.

[0146] The above are only preferred embodiments of the present application, and do not limit the patent scope of the present application, and any equivalent structure or equivalent flow transformation made by using the content of the present application specification and drawings, or directly or indirectly applied to other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for controlling a storage converter based on a coupling of network construction and network following, characterized in that, The method comprises the following steps: Step one: extract and process the output current of the energy storage converter, compare the output current with the reference current to obtain a comparison signal, and the reference current is obtained based on the reference power; Step two: input the comparison signal into the pre-constructed grid-forming control branch to obtain a first reference voltage, and the grid-forming control branch is used to provide voltage support; Step three: input the comparison signal into the pre-constructed grid-following control branch to obtain a second reference voltage, and the grid-following control branch is used to provide current response; Step four: input the first reference voltage and the second reference voltage into the pre-constructed grid-forming-grid-following coupling model to obtain a coupling voltage, and the grid-forming-grid-following coupling model is used to superimpose the first reference voltage and the second reference voltage; Step five: control the energy storage converter based on the coupling voltage; The step one comprises: A1: extracting the output current from the inverter of the energy storage converter and performing coordinate transformation on the output current; A2: subtracting the output current after the coordinate transformation from the reference current, and defining the difference value as the comparison signal; The step two comprises: B1: constructing the grid-forming control branch, which is a grid-forming virtual oscillator control structure comprising at least a virtual capacitor and a virtual inductor; B2: inputting the comparison signal into the grid-forming virtual oscillator control structure, outputting the virtual capacitor voltage and the virtual inductor current, and defining them as the first reference voltage; The first reference voltage is represented as The control equation of the networked virtual oscillator control structure is: wherein, is a grid-forming type is an axis voltage output, is a grid-forming type is an axis voltage output, is an inverter output phase voltage effective value, is an inverter output frequency reference, is a scaling factor for input current, is a scaling factor for output voltage, is the virtual capacitance, is a control parameter for controlling the speed of voltage convergence, is a defined rotation angle, is is an axis current input, is is an axis current input.

2. The network build-follow-up coupling-based energy storage converter control method of claim 1, wherein, The step three comprises: C1: constructing the grid-following control branch, which comprises a grid-following current control unit and a coupling unit; C2: inputting the comparison signal into the grid-following control branch, outputting after the coupling unit, and defining it as the second reference voltage.

3. The network build-follow-up coupling-based energy storage converter control method of claim 2, wherein, The grid-following current control unit is controlled by a grid-following current control equation, which is: wherein, is a follow-the-leader type axle voltage output, is a follow-the-leader type axle voltage output, is axle current input, is axle current input, is a coupling factor.

4. The network build-follow-up coupling-based energy storage converter control method of claim 3, wherein, The coupling unit is provided with a coupling coefficient, and the coupling coefficient is obtained based on a dynamic response time constant, which is determined based on a dynamic response time constant formula, which is: wherein, is the determined dynamic response time constant, is the coupling coefficient, is the grid-side impedance, and the coupling coefficient is larger, the dynamic response time constant is smaller, the response speed of the energy storage converter is faster, is the reference value of the active power.

5. The network build-follow-up coupling-based energy storage converter control method of claim 4, wherein, The step four comprises: D1: constructing the grid-forming-grid-following coupling model, which takes the first reference voltage and the second reference voltage as input, and the result after superimposing the first reference voltage and the second reference voltage as output; wherein the superposition of the first reference voltage and the second reference voltage is performed through a grid-forming-grid-following coupling control equation, which is: wherein, is a result of a superposition of the first reference voltage and the second reference voltage, is an output of the network-forming control branch, is an output of the network-following control branch; D2: inputting the first reference voltage and the second reference voltage into the grid-forming-grid-following coupling model, outputting and defining as the coupling voltage.

6. The network build-follow-up coupling-based energy storage converter control method of claim 5, wherein, When the energy storage converter is in an inductive grid condition, the method further comprises the following steps: E1: setting the rotation angle to so that the inverter exhibits a droop characteristic of active power versus grid frequency and a droop characteristic of reactive power versus grid voltage amplitude; E2: increasing the coupling coefficient to reduce the dynamic response time constant, reducing the response time of the active power; When the energy storage converter has a grid frequency drop and / or a voltage drop, the method further comprises the following steps: F1: maintaining the output voltage and frequency through the self-synchronization characteristics of the grid-forming control branch; F2: compensating the current error quickly through the current control of the grid-following control branch.

7. A grid-forming and grid-following coupled energy storage converter control system applying the grid-forming and grid-following coupled energy storage converter control method according to any one of claims 1-6, characterized in that, The system comprises: a current comparison module configured to extract and process an output current of the energy storage converter, compare the output current with a reference current to obtain a comparison signal, and obtain the reference current based on a reference power; a grid-forming control module configured to input the comparison signal into a pre-constructed grid-forming control branch to obtain a first reference voltage, and provide voltage support by the grid-forming control branch; a grid-following control module configured to input the comparison signal into a pre-constructed grid-following control branch to obtain a second reference voltage, and provide current response by the grid-following control branch; a grid-forming-grid-following coupling module configured to input the first reference voltage and the second reference voltage into a pre-constructed grid-forming-grid-following coupling model to obtain a coupling voltage, and superimpose the first reference voltage and the second reference voltage by the grid-forming-grid-following coupling model; a control execution module configured to control the energy storage converter based on the coupling voltage.

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