Virtual impedance current-limiting control method for improving transient stability of network-forming type energy storage converter

Abstract

The invention discloses a virtual impedance current-limiting control method for improving transient stability of a network-forming type energy storage converter. The method comprises the following steps: constructing an energy storage converter transient power model of the energy storage converter, wherein the energy storage converter transient power model takes virtual impedance current limiting into account; according to the transient power model of the energy storage converter, performing transient power angle instability state simulation analysis of the energy storage converter, and determining an adaptive virtual impedance optimization control strategy of the energy storage converter; determining the adaptive impedance ratio of the energy storage converter according to the actual angular frequency of the energy storage converter and the adaptive virtual impedance optimization control strategy; and performing adaptive impedance current limiting control on the energy storage converter based on the adaptive impedance ratio.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage converter stability control, and more specifically, to a virtual impedance current limiting control method for improving the transient stability of a grid-type energy storage converter. Background Art

[0002] Global energy shortage and environmental pollution problems are becoming increasingly serious. Building a power system architecture dominated by new energy has become one of the core development strategies of various countries. However, due to the intermittent and volatile nature of new energy and the access to the power grid through power electronic devices, the power quality and stability of the power grid are threatened. The PCS, as the core equipment for smoothing the power fluctuations of new energy, undertakes tasks such as bidirectional power flow and conversion, and has broad application prospects in the future.

[0003] Energy storage converters are divided into grid-following control type and grid-building control type, among which grid-building control type energy storage converter is the current research hotspot. Grid-building PCS can operate in the range of -1 to 1 p.u. of active power. There is a negative input power, in which case a deceleration instability will occur. Due to the voltage source characteristics presented to the outside by the grid-building PCS, it is easy to cause overcurrent in the device when a fault occurs. The virtual impedance strategy can effectively limit the fault current, but it may cause transient stability problems. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a virtual impedance current limiting control method for improving the transient stability of a grid-type energy storage converter.

[0005] According to one aspect of the present invention, a virtual impedance current limiting control method for improving the transient stability of a grid-connected energy storage converter is provided, comprising:

[0006] Construct a transient power model of the energy storage converter taking into account virtual impedance current limiting;

[0007] According to the transient power model of the energy storage converter, the transient power angle instability morphology of the energy storage converter is simulated and analyzed to determine the adaptive virtual impedance optimization control strategy of the energy storage converter;

[0008] Determine the adaptive impedance ratio of the energy storage converter according to the actual angular frequency of the energy storage converter and the adaptive virtual impedance optimization control strategy;

[0009] Adaptive impedance current limiting control is performed on the energy storage converter based on the adaptive impedance ratio.

[0010] Optionally, a transient power angle instability morphology simulation analysis of the energy storage converter is performed according to the transient power model of the energy storage converter to determine an adaptive virtual impedance optimization control strategy of the energy storage converter, including:

[0011] Perform simulation based on the transient power model of the energy storage converter to obtain the power angle characteristic curve;

[0012] The acceleration instability form and deceleration instability form of the energy storage converter are analyzed according to the power angle characteristic curve, and the adaptive virtual impedance optimization control strategy of the energy storage converter is determined.

[0013] Optionally, the expression of the adaptive virtual impedance ratio optimization control strategy is:

[0014]

[0015] Where σ0 is the initial virtual impedance ratio, k i is the integral coefficient, w is the actual angular frequency of the energy storage converter, w0 is the rated angular frequency, σ min is the lower limit value of the limiting module in the virtual impedance control, σ max It is the upper limit value of the limiting module in the virtual impedance control.

[0016] Optionally, the expression of adaptive impedance current limiting control is:

[0017] X V =R V σ a

[0018] in,

[0019] R v =max(k pvi (II n ),0)

[0020] In the formula, R v and X v are virtual resistance and virtual reactance respectively, σ a is the adaptive virtual impedance ratio, I is the output current amplitude, I n is the rated current amplitude, k pvi is the virtual impedance adjustment coefficient, which changes with σ in the transient process. a change.

[0021] According to another aspect of the present invention, a virtual impedance current limiting control device for improving the transient stability of a grid-type energy storage converter is provided, comprising:

[0022] A construction module for constructing a transient power model of an energy storage converter taking into account virtual impedance current limiting;

[0023] An analysis module is used to perform a simulation analysis of the transient power angle instability morphology of the energy storage converter according to the transient power model of the energy storage converter, and determine an adaptive virtual impedance optimization control strategy for the energy storage converter;

[0024] A determination module, used to determine the adaptive impedance ratio of the energy storage converter according to the actual angular frequency of the energy storage converter and the adaptive virtual impedance optimization control strategy;

[0025] The control module is used to perform adaptive impedance current limiting control on the energy storage converter based on the adaptive impedance ratio.

[0026] According to another aspect of the present invention, a computer-readable storage medium is provided, wherein the storage medium stores a computer program, and the computer program is used to execute the method of any one of the above aspects of the present invention.

[0027] According to another aspect of the present invention, an electronic device is provided, comprising: a processor; a memory for storing instructions executable by the processor; the processor is configured to read the executable instructions from the memory and execute the instructions to implement the method described in any one of the above aspects of the present invention.

[0028] Therefore, the present application proposes a virtual impedance current limiting control method for improving the transient stability of a grid-type energy storage converter. By simulating and analyzing the transient power angle instability morphology of the energy storage converter, an adaptive virtual impedance optimization control strategy for the energy storage converter is constructed. The energy storage converter is adaptively controlled by impedance current limiting through the adaptive virtual impedance optimization control strategy, which can effectively improve the transient stability margin of the energy storage converter during the transient period. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] A more complete understanding of exemplary embodiments of the present invention may be obtained by referring to the following drawings:

[0030] Figure 1 It is a flow chart of a virtual impedance current limiting control method for improving the transient stability of a grid-type energy storage converter provided by an exemplary embodiment of the present invention;

[0031] Figure 2 It is a schematic diagram of energy storage converter control and system structure provided by an exemplary embodiment of the present invention;

[0032] Figure 3 is a schematic diagram of a virtual impedance structure provided by an exemplary embodiment of the present invention;

[0033] Figure 4 It is a schematic diagram of the generation mechanism of acceleration instability and deceleration instability provided by an exemplary embodiment of the present invention;

[0034] Figure 5 is a schematic diagram of the effect of a virtual impedance ratio on a power angle characteristic curve provided by an exemplary embodiment of the present invention;

[0035] Figure 6 is a schematic diagram of an improved virtual impedance strategy proposed by the present invention provided by an exemplary embodiment of the present invention;

[0036] Figure 7a to Figure 7c It is a schematic diagram of simulated active power, output current and power angle waveform of a conventional virtual impedance under a discharge state provided by an exemplary embodiment of the present invention;

[0037] Figure 8a to Figure 8c It is a schematic diagram of simulated active power, output current and power angle waveform of a traditional virtual impedance under charging state provided by an exemplary embodiment of the present invention;

[0038] Figure 9a to Figure 9c It is a schematic diagram of simulated active power, output current and power angle waveform of an improved virtual impedance effect under a discharge state provided by an exemplary embodiment of the present invention;

[0039] Figure 10a to Figure 10c It is a schematic diagram of simulated active power, output current and power angle waveform of improved virtual impedance action in charging state provided by an exemplary embodiment of the present invention;

[0040] Fig.11 It is a structural schematic diagram of a virtual impedance current limiting control device for improving the transient stability of a grid-type energy storage converter provided by an exemplary embodiment of the present invention;

[0041] Fig.12 This is a structure of an electronic device provided by an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0042] Below, the exemplary embodiments according to the present invention will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments of the present invention, and it should be understood that the present invention is not limited to the exemplary embodiments described here.

[0043] It should be noted that the relative arrangement of components and steps, the numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.

[0044] Those skilled in the art can understand that the terms "first" and "second" in the embodiments of the present invention are only used to distinguish different steps, devices or modules, etc., and neither represent any specific technical meaning nor indicate the necessary logical order between them.

[0045] It should also be understood that, in the embodiments of the present invention, “plurality” may refer to two or more than two, and “at least one” may refer to one, two or more than two.

[0046] It should also be understood that any component, data or structure mentioned in the embodiments of the present invention can generally be understood as one or more, unless explicitly limited or otherwise indicated in the context.

[0047] In addition, the term "and / or" in the present invention is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects before and after are in an "or" relationship.

[0048] It should also be understood that the description of the various embodiments of the present invention focuses on the differences between the various embodiments, and the same or similar aspects thereof can be referenced to each other, and for the sake of brevity, they will not be described one by one.

[0049] At the same time, it should be understood that for the convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship.

[0050] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0051] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0052] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0053] Embodiments of the present invention can be applied to electronic devices such as terminal devices, computer systems, servers, etc., which can operate with many other general or special computing system environments or configurations. Examples of well-known terminal devices, computing systems, environments and / or configurations suitable for use with electronic devices such as terminal devices, computer systems, servers, etc. include, but are not limited to: personal computer systems, server computer systems, thin clients, thick clients, handheld or laptop devices, microprocessor-based systems, set-top boxes, programmable consumer electronics, network personal computers, small computer systems, large computer systems, and distributed cloud computing technology environments including any of the above systems, etc.

[0054] Electronic devices such as terminal devices, computer systems, servers, etc. can be described in the general context of computer system executable instructions (such as program modules) executed by computer systems. Generally, program modules can include routines, programs, object programs, components, logic, data structures, etc., which perform specific tasks or implement specific abstract data types. Computer systems / servers can be implemented in a distributed cloud computing environment, where tasks are performed by remote processing devices linked through a communication network. In a distributed cloud computing environment, program modules can be located on local or remote computing system storage media including storage devices.

[0055] Exemplary Methods

[0056] Figure 1 1 is a flow chart of a virtual impedance current limiting control method for improving the transient stability of a grid-type energy storage converter provided by an exemplary embodiment of the present invention. This embodiment can be applied to electronic devices, such as Figure 1 As shown, the virtual impedance current limiting control method 100 for improving the transient stability of the grid-type energy storage converter includes the following steps:

[0057] Step 101, constructing a transient power model of the energy storage converter taking into account virtual impedance current limiting;

[0058] Step 102, performing a simulation analysis of the transient power angle instability morphology of the energy storage converter according to the transient power model of the energy storage converter, and determining an adaptive virtual impedance optimization control strategy for the energy storage converter;

[0059] Step 103, determining the adaptive impedance ratio of the energy storage converter according to the actual angular frequency of the energy storage converter and the adaptive virtual impedance optimization control strategy;

[0060] Step 104: performing adaptive impedance current limiting control on the energy storage converter based on the adaptive impedance ratio.

[0061] Specifically, the present invention proposes a virtual impedance current limiting control device applicable to the full power range of the energy storage converter, which can effectively improve the transient stability margin of the energy storage converter during the transient period. The specific implementation process is as follows:

[0062] Step 1: Construction of transient power model of energy storage converter considering virtual impedance current limiting

[0063] The PCS grid-connected topology and control structure using virtual impedance current limiting are as follows: Figure 2 As shown. f and C f is the filter capacitor and filter inductor of the energy storage converter, Z g is the line impedance, U pcc is the voltage at PCC, U dcIt is a DC voltage, which is usually controlled by the previous converter. In an ideal situation, U dc Can be considered as a constant value.

[0064] Figure 2 In the control structure, active power control, reactive power control and virtual impedance control are included. Active power control and reactive power control are used to generate the PCC point voltage reference vector E = E∠θ. After adding virtual impedance control, it becomes E ref =E∠θ ref , where I is the output current vector, expressed as I = I∠θ s Since the voltage and current inner loop has a large bandwidth, its influence on the PCS transient characteristics can be ignored, so the PCS transient power angle characteristics are mainly determined by the power outer loop and virtual impedance.

[0065] The PCS power outer loop adopts virtual synchronous machine control, and the expression is:

[0066]

[0067] E=V0+n q (Q0-Q) (2)

[0068] Where J is the virtual inertia constant, D p is the damping coefficient, n q is the reactive droop coefficient, P0 and Q0 are the input active power and rated reactive power, P and Q are the output active power and output reactive power, ω0 and ω are the rated angular frequency and output angular frequency, and V0 is the voltage rating.

[0069] The structure of the virtual impedance strategy is as follows Figure 3 As shown, its expression is:

[0070] R v =max(k pvi (II n ),0) (3)

[0071] X v =R v σ v (4)

[0072] In the formula, R v and X v are virtual resistance and virtual reactance respectively, σ v is the virtual impedance ratio, I is the output current amplitude, I n is the rated current amplitude, k pvi is the virtual impedance adjustment coefficient.

[0073] In order to obtain the analytical expressions of the output active power P and reactive power Q under the action of PCS virtual impedance, the PCS equivalent circuit is first constructed, as shown in Figure 2 As shown, a virtual PCC point is defined, and the power flow at this point is easy to obtain, as shown in the following formula:

[0074]

[0075] Where P vir is the virtual active power, Q vir is virtual reactive power, δ vir is the virtual power angle, expressed as δ vir =θ-θ g , R eq =R v +R,X eq =X v +X, the expressions of a1, b1 and b2 are as follows:

[0076]

[0077] The amplitude of the output current I can be determined by the following formula:

[0078]

[0079] Then the expression of PCS output power can be obtained:

[0080]

[0081] In the formula, the phase angle The expression is The expressions of a2, a3, b3, b4, b5, b6 are as follows:

[0082]

[0083] Substituting equation (10) into equation (2) yields E with respect to δ vir The expression is:

[0084]

[0085] In the formula,

[0086] Substituting equation (12) into equation (9), we can get the output power P and the virtual power angle δ vir The relationship between them is used for subsequent transient stability analysis.

[0087] Step 2: Influence of virtual impedance on transient power angle instability of energy storage converter

[0088] Since the energy storage converter can operate in both charging and discharging states, and the active power regulation range is -1 to 1 p.u., when a large disturbance such as a short circuit fault occurs in the system, acceleration instability and deceleration instability can occur. According to the energy storage converter power model of formula (9), the mechanism of these two instability forms can be analyzed using the power angle characteristic curve, such as Figure 4 shown.

[0089] When the PCS is in the discharge state, the input power P 01 is a positive value. When PCS passes point f', the corresponding instability form is accelerated instability, which is similar to the accelerated instability of the synchronous machine and will not be described in detail in this article.

[0090] When the PCS is in charging state, the input power P 02 is a negative value, and the corresponding instability form is deceleration instability. Let the input power P 02 Equal to output power P, input power P 02 There are two intersection points with the power angle curve during normal operation, where point a is the stable equilibrium point and point f is the unstable equilibrium point.

[0091] Assuming that the system initially runs at point a, the corresponding power angle is δ0. After the fault occurs, the system's operating point moves from point a to point b. Because P0 is less than P, the angular frequency of PCS decreases, and the system will decelerate to point c.

[0092] The fault is cleared at point c, and the corresponding removal angle is δ c , the system operating point moves from point c to point d, at this time P 02 When the PCS angular frequency is greater than P, the PCS angular frequency increases, but due to the inertia of the system, the PCS angular frequency is still less than the rated angular frequency, and the power angle will continue to decrease until the system runs to point e, at which point the PCS angular frequency is equal to the rated angular frequency. In this stage, the power angle δ corresponding to point e is d Only the power angle δ corresponding to point f is smaller than max , the system can return to stability, otherwise the system will pass point f and become decelerated and unstable.

[0093] To study the virtual impedance ratio σ v The impact on the transient characteristics of the meshed PCS is based on the PCS transient power model based on virtual impedance current limiting. Figure 5 The virtual impedance ratio σ is given by v The power angle curve changes when the power angle changes. From the figure, we can see that the virtual impedance ratio σ v The impacts on the two instability forms of the system are completely different.

[0094] From the previous analysis, it can be seen that when the PCS operating point exceeds the unstable equilibrium point, the system will lose stability. In order to reflect the transient stability margin of the system, the maximum power angle overshoot of the PCS is defined as:

[0095] δ cm =|δ UEP -δ SEP | (13)

[0096] In the formula, δ SEP and δ UEP are the power angles corresponding to the stable equilibrium point and the unstable equilibrium point respectively.

[0097] Figure 5 In v The larger the value, the greater the maximum value of the power angle curve P max and the minimum value P min The larger the value, the greater the v The increase of improves the power transmission capability of PCS in the discharge state, but weakens the power transmission capability of PCS in the charge state. v The larger the δ cm1 The larger the δ cm2 The smaller the v The increase of improves the transient stability margin of PCS in the discharge state and weakens the transient stability margin of PCS in the charging state. Therefore, through the above analysis, a larger σ v It will increase the risk of PCS deceleration instability and reduce the risk of PCS acceleration instability.

[0098] Step 3: Adaptive virtual impedance optimization control strategy

[0099] Based on the above analysis, the value of the virtual impedance ratio needs to weigh the system transient stability margin under the PCS charging and discharging states, and minimize the risk of PCS acceleration instability and deceleration instability. Based on this, an improved virtual impedance strategy is proposed, which can take into account both the PCS charging and discharging working states, adaptively adjust the virtual impedance ratio, and thus improve the transient stability of the system. The structural block diagram of the proposed virtual impedance is shown in Figure 6 shown.

[0100] In the figure, σ0 is the initial virtual impedance ratio to ensure good voltage and current dynamic characteristics. The PCS angular frequency change is processed by the integration module and superimposed with the initial virtual impedance ratio σ0, and then the limiting module outputs the adaptive impedance ratio σ a , whose expression is:

[0101]

[0102] Among them, k i is the integral coefficient, the lower limit value of the limiting module σ min is 0.1, ensuring that the impedance ratio is not negative and making the virtual impedance close to pure resistance, the maximum value σ maxis 10, which makes the virtual impedance close to pure inductance. In addition, the virtual impedance adjustment coefficient k pvi In the transient process, it follows σ a Varies.

[0103] Figure 7a to Figure 7c and Figure 8a to Figure 8c This is the simulation result under the traditional virtual impedance strategy. At t = 5s, the grid voltage drops to 0.7pu, and the system enters a continuous low voltage state. Figure 7a to Figure 7c The PCS is in the discharge state, and the input power is 0.7pu. Figure 8a to Figure 8c The PCS is in charging state, the input power is -0.7pu, and the virtual impedance ratio in both figures is 3.

[0104] Depend on Figure 7a to Figure 7c and Figure 8a to Figure 8c It can be seen that when the system enters a continuous low voltage state, the PCS experiences acceleration instability and deceleration instability, power and current oscillation, and power angle divergence. The reason is that during the fault stage, the grid voltage drops, the maximum value of the system output power decreases, the minimum value increases, and the power transmission capacity decreases, resulting in no balance point for the PCS after the fault, and the system eventually loses stability.

[0105] Figure 9a to Figure 9c and Figure 10a to Figure 10c These are the simulation results using the improved virtual impedance strategy. The initial states and fault conditions in the two figures are the same as those mentioned above.

[0106] Figure 9a to Figure 9c In the example, after a fault occurs, since the input power is greater than the output power, the PCS accelerates. At this time, the angular frequency change is greater than 0, the virtual impedance ratio increases adaptively, the maximum output power increases, and a new balance point is generated. The PCS eventually resumes stable operation and the output active power remains unchanged, avoiding the risk of accelerated instability.

[0107] Figure 10a to Figure 10c In the simulation, the PCS decelerates after the fault. As the virtual impedance ratio is adaptively reduced, the transient stability margin of the system in the charging state is improved, and the PCS finally operates stably at the new operating point. The above simulation verifies the effectiveness of the proposed virtual impedance strategy.

[0108] Therefore, the present application proposes a virtual impedance current limiting control method for improving the transient stability of a grid-type energy storage converter. By simulating and analyzing the transient power angle instability morphology of the energy storage converter, an adaptive virtual impedance optimization control strategy for the energy storage converter is constructed. The energy storage converter is adaptively controlled by impedance current limiting through the adaptive virtual impedance optimization control strategy, which can effectively improve the transient stability margin of the energy storage converter during the transient period.

[0109] Exemplary Devices

[0110] Fig.11 1 is a schematic diagram of the structure of a virtual impedance current limiting control device for improving the transient stability of a grid-type energy storage converter provided by an exemplary embodiment of the present invention. Fig.11 As shown, the device 1100 includes:

[0111] A construction module 1110 is used to construct a transient power model of the energy storage converter taking into account virtual impedance current limiting;

[0112] The analysis module 1120 is used to perform a simulation analysis of the transient power angle instability morphology of the energy storage converter according to the transient power model of the energy storage converter, and determine the adaptive virtual impedance optimization control strategy of the energy storage converter;

[0113] A determination module 1130, configured to determine an adaptive impedance ratio of the energy storage converter according to an actual angular frequency of the energy storage converter and an adaptive virtual impedance optimization control strategy;

[0114] The control module 1140 is used to perform adaptive impedance current limiting control on the energy storage converter based on the adaptive impedance ratio.

[0115] Optionally, the analysis module 1120 includes:

[0116] A simulation submodule is used to simulate the transient power model of the energy storage converter and obtain a power angle characteristic curve;

[0117] The analysis submodule is used to analyze the acceleration instability form and the deceleration instability form of the energy storage converter according to the power angle characteristic curve, and determine the adaptive virtual impedance optimization control strategy of the energy storage converter.

[0118] Optionally, the expression of the adaptive virtual impedance ratio optimization control strategy is:

[0119]

[0120] Where σ0 is the initial virtual impedance ratio, k i is the integral coefficient, w is the actual angular frequency of the energy storage converter, w0 is the rated angular frequency, σ min is the lower limit value of the limiting module in the virtual impedance control, σ max It is the upper limit value of the limiting module in the virtual impedance control.

[0121] Optionally, the expression of adaptive impedance current limiting control is:

[0122] X V =R V σ a

[0123] in,

[0124] Rv =max(k pvi (II n ),0)

[0125] In the formula, R v and X v are virtual resistance and virtual reactance respectively, σ a is the adaptive virtual impedance ratio, I is the output current amplitude, I n is the rated current amplitude, k pvi is the virtual impedance adjustment coefficient, which changes with σ in the transient process. a change.

[0126] Exemplary Electronic Devices

[0127] Fig.12 This is a structure of an electronic device provided by an exemplary embodiment of the present invention. Fig.12 As shown, the electronic device 120 includes one or more processors 121 and a memory 122 .

[0128] The processor 121 may be a central processing unit (CPU) or other forms of processing units having data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions.

[0129] The memory 122 may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, random access memory (RAM) and / or cache memory (cache), etc. The non-volatile memory may include, for example, read-only memory (ROM), hard disk, flash memory, etc. One or more computer program instructions may be stored on the computer-readable storage medium, and the processor 121 may run the program instructions to implement the methods of the software programs of the various embodiments of the present invention described above and / or other desired functions. In one example, the electronic device may also include: an input device 123 and an output device 124, which are interconnected via a bus system and / or other forms of connection mechanisms (not shown).

[0130] In addition, the input device 123 may also include, for example, a keyboard, a mouse, etc.

[0131] The output device 124 can output various information to the outside, and can include, for example, a display, a speaker, a printer, a communication network and a remote output device connected thereto.

[0132] Of course, to simplify, Fig.12Only some of the components related to the present invention in the electronic device are shown, and components such as a bus, an input / output interface, etc. are omitted. In addition, the electronic device may further include any other appropriate components according to specific application conditions.

[0133] Exemplary computer program products and computer-readable storage media

[0134] In addition to the above-mentioned methods and devices, an embodiment of the present invention may also be a computer program product, which includes computer program instructions, which, when executed by a processor, enable the processor to execute the steps of the method according to various embodiments of the present invention described in the above-mentioned "Exemplary Method" section of this specification.

[0135] The computer program product may be written in any combination of one or more programming languages ​​to write program code for performing the operations of the embodiments of the present invention, including object-oriented programming languages ​​such as Java, C++, etc., and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, as a separate software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0136] In addition, an embodiment of the present invention may also be a computer-readable storage medium having computer program instructions stored thereon, which, when executed by a processor, enable the processor to execute the steps of the method according to various embodiments of the present invention described in the above “Exemplary Method” section of this specification.

[0137] The computer readable storage medium can adopt any combination of one or more readable media. The readable medium can be a readable signal medium or a readable storage medium. The readable storage medium can include, for example, but is not limited to, a system, system or device of electricity, magnetism, light, electromagnetic, infrared, or semiconductor, or any combination of the above. More specific examples (non-exhaustive list) of readable storage media include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0138] The basic principle of the present invention is described above in conjunction with specific embodiments. However, it should be pointed out that the advantages, strengths, effects, etc. mentioned in the present invention are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. must be possessed by each embodiment of the present invention. In addition, the specific details disclosed above are only for the purpose of illustration and facilitation of understanding, rather than limitation, and the above details do not limit the present invention to being implemented by adopting the above specific details.

[0139] Each embodiment in this specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the system embodiment, since it basically corresponds to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0140] The block diagrams of the devices, systems, equipment, and systems involved in the present invention are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagram. As will be appreciated by those skilled in the art, these devices, systems, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, referring to "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "and / or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The word "such as" used here refers to the phrase "such as but not limited to", and can be used interchangeably with it.

[0141] The method and system of the present invention may be implemented in many ways. For example, the method and system of the present invention may be implemented by software, hardware, firmware or any combination of software, hardware, firmware. The above order of steps for the method is only for illustration, and the steps of the method of the present invention are not limited to the order specifically described above, unless otherwise specifically stated. In addition, in some embodiments, the present invention may also be implemented as a program recorded in a recording medium, which includes machine-readable instructions for implementing the method according to the present invention. Thus, the present invention also covers a recording medium storing a program for executing the method according to the present invention.

[0142] It should also be noted that in the system, device and method of the present invention, each component or each step can be decomposed and / or recombined. These decompositions and / or recombinations should be regarded as equivalent schemes of the present invention. The above description of the disclosed aspects is provided to enable any technician in the field to make or use the present invention. Various modifications to these aspects are very obvious to those skilled in the art, and the general principles defined here can be applied to other aspects without departing from the scope of the present invention. Therefore, the present invention is not intended to be limited to the aspects shown here, but in accordance with the widest range consistent with the principles and novel features disclosed here.

[0143] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present invention to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A virtual impedance current limiting control method for improving the transient stability of a grid-type energy storage converter, characterized in that: include: Construct a transient power model of the energy storage converter taking into account virtual impedance current limiting; Performing a simulation analysis of the transient power angle instability morphology of the energy storage converter according to the transient power model of the energy storage converter, and determining an adaptive virtual impedance optimization control strategy for the energy storage converter; Determining an adaptive impedance ratio of the energy storage converter according to the actual angular frequency of the energy storage converter and the adaptive virtual impedance optimization control strategy; Adaptive impedance current limiting control is performed on the energy storage converter based on the adaptive impedance ratio.

2. The method according to claim 1, characterized in that According to the transient power model of the energy storage converter, a transient power angle instability morphology simulation analysis of the energy storage converter is performed to determine an adaptive virtual impedance optimization control strategy of the energy storage converter, including: Perform simulation according to the transient power model of the energy storage converter to obtain a power angle characteristic curve; The acceleration instability form and the deceleration instability form of the energy storage converter are analyzed according to the power angle characteristic curve to determine an adaptive virtual impedance optimization control strategy for the energy storage converter.

3. The method according to claim 1, characterized in that The expression of the adaptive virtual impedance ratio optimization control strategy is: Where σ0 is the initial virtual impedance ratio, k i is the integral coefficient, w is the actual angular frequency of the energy storage converter, w0 is the rated angular frequency, σ min is the lower limit value of the limiting module in the virtual impedance control, σ max It is the upper limit value of the limiting module in the virtual impedance control.

4. The method according to claim 1, characterized in that: The expression of the adaptive impedance current limiting control is: X V =R V v a in, R v =max(k pvi (I-I n ),0) In the formula, R v and X v are virtual resistance and virtual reactance respectively, σ a is the adaptive virtual impedance ratio, I is the output current amplitude, I n is the rated current amplitude, k pvi is the virtual impedance adjustment coefficient, which changes with σ in the transient process. a change.

5. A virtual impedance current limiting control device for improving the transient stability of a grid-type energy storage converter, characterized in that: include: A construction module for constructing a transient power model of an energy storage converter taking into account virtual impedance current limiting; An analysis module, used to perform a simulation analysis of the transient power angle instability morphology of the energy storage converter according to the transient power model of the energy storage converter, and determine an adaptive virtual impedance optimization control strategy for the energy storage converter; A determination module, used to determine the adaptive impedance ratio of the energy storage converter according to the actual angular frequency of the energy storage converter and the adaptive virtual impedance optimization control strategy; A control module is used to perform adaptive impedance current limiting control on the energy storage converter based on the adaptive impedance ratio.

6. The device according to claim 5, characterized in that Analysis modules, including: A simulation submodule, used for performing simulation according to the transient power model of the energy storage converter to obtain a power angle characteristic curve; The analysis submodule is used to analyze the acceleration instability form and the deceleration instability form of the energy storage converter according to the power angle characteristic curve, and determine the adaptive virtual impedance optimization control strategy of the energy storage converter.

7. The device according to claim 5, characterized in that The expression of the adaptive virtual impedance ratio optimization control strategy is: Where σ0 is the initial virtual impedance ratio, k i is the integral coefficient, w is the actual angular frequency of the energy storage converter, w0 is the rated angular frequency, σ min is the lower limit value of the limiting module in the virtual impedance control, σ max It is the upper limit value of the limiting module in the virtual impedance control.

8. The device according to claim 5, characterized in that The expression of the adaptive impedance current limiting control is: X V =R V s a in, R v =max(k pvi (I-I n ),0) In the formula, R v and X v are virtual resistance and virtual reactance respectively, σ a is the adaptive virtual impedance ratio, I is the output current amplitude, I n is the rated current amplitude, k pvi is the virtual impedance adjustment coefficient, which changes with σ in the transient process. a change.

9. A computer-readable storage medium, characterized in that: The storage medium stores a computer program, and the computer program is used to execute the method according to any one of claims 1 to 4.

10. An electronic device, characterized in that: The electronic device comprises: processor; a memory for storing instructions executable by the processor; The processor is used to read the executable instructions from the memory and execute the instructions to implement the method described in any one of claims 1 to 4.

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