Transient state synchronous stability control method for network construction type SVG (Static Var Generator) based on alternating current and direct current voltage hybrid control

Abstract

The invention discloses a networking type SVG transient synchronous stability control method based on AC / DC voltage hybrid control, and the method comprises the steps: calculating an internal potential phase angle of a networking type SVG system according to the operation parameter data of the networking type SVG system based on a DC voltage self-synchronization control module; judging whether the phase angle difference between the phase angle at the port of the networking type SVG system and the internal potential phase angle is smaller than 2 degrees or not, and judging that the networking type SVG system is stable when the phase angle difference is smaller than or equal to 2 degrees; when the phase angle difference exceeds 2 degrees, AC voltage stability enhancement control is carried out on the network construction type SVG system, and the output current of the network construction type SVG system is calculated; and judging whether the output current reaches a preset current amplitude limiting value or not, if the output current is greater than or equal to the current amplitude limiting value, judging that the current of the network construction type SVG system is saturated and has an instability risk, and implementing direct-current voltage stability enhancement control on the network construction type SVG system.

Description

Technical Field

[0001] The present invention relates to the technical field of stability analysis of new energy power systems, and more specifically, to a transient synchronous stability control method of a grid-type SVG based on AC / DC voltage hybrid control. Background Art

[0002] With the rapid development of new energy, the power system has gradually shown the "double high" characteristics of a high proportion of renewable energy and a high proportion of power electronic equipment. This change has led to a significant decrease in the inertia and short-circuit capacity of the power grid, thereby weakening the stability and anti-interference ability of the system, and bringing many challenges to the safe and stable operation of the power system. Studies have shown that when the static var generator (SVG) is running together with the new energy grid-connected system, it can significantly improve the voltage stability of the system. The existing SVG mostly uses a phase-locked loop (PLL) to achieve grid synchronization with the grid, and directly realizes reactive compensation for the new energy station by controlling the reactive current. However, the essence of reactive power compensation is to achieve effective support for the node voltage. Since SVG can be equivalent to a variable admittance and current source, and the stability of PLL control under weak power grid is poor, it can usually only provide voltage support for the system in quasi-steady state, and the voltage response speed is limited, which is difficult to meet the voltage support requirements of wide bandwidth.

[0003] Research in recent years has shown that compared with PLL-based grid-following control, SVG under grid-building control has significant advantages in providing grid power and frequency support, especially in being able to operate independently in island mode. In addition, grid-building control shows stronger robustness to grid strength. Its main feature is that it is free from the frequency tracking mechanism that relies on the traditional phase-locked loop, adopts the grid-connected synchronization characteristics similar to those of traditional synchronous generators, and presents voltage source characteristics. Nevertheless, while simulating the inertia and damping characteristics of traditional synchronous generators, it still inevitably inherits some inherent problems of traditional synchronous generators, such as transient stability and low-frequency oscillation problems. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a transient synchronous stability control method for a grid-type SVG based on AC / DC voltage hybrid control.

[0005] According to one aspect of the present invention, a method for transient synchronous stability control of a grid-type SVG based on AC / DC voltage hybrid control is provided, comprising: Construct a DC voltage self-synchronization control module for a grid-type SVG system; According to the operation parameter data of the grid-forming SVG system based on the DC voltage self-synchronous control module, the internal potential phase angle of the grid-forming SVG system is calculated; Determine whether the phase angle difference between the phase angle at the port of the meshed SVG system and the internal potential phase angle is less than 2°, and determine that the meshed SVG system is stable when the phase angle difference is less than or equal to 2°; When the phase angle difference exceeds 2°, AC voltage stability enhancement control is implemented on the grid-forming SVG system based on the DC voltage self-synchronization control module, and the output current of the grid-forming SVG system is calculated; Determine whether the output current of the meshed SVG system reaches the preset current limit value. If the output current is greater than or equal to the current limit value, the meshed SVG system is judged to be current saturated and there is a risk of instability, and implement DC voltage stability enhancement control on the meshed SVG system based on the DC voltage self-synchronization control module.

[0006] Optionally, the DC voltage self-synchronous control module is composed of DC synchronous control, reactive power droop control and AC voltage control, wherein the DC synchronous control is expressed as: In the formula, Output phase for synchronous control of DC voltage; is the DC voltage of SVG, It is the reference value of DC voltage control of SVG; T , J , D They are the proportional coefficient, inertia coefficient, and damping coefficient of DC voltage control; is the rated angular frequency; s is the Laplace operator; Reactive power droop control is expressed as: In the formula, V dref is the voltage d-axis component reference value, K Q is the reactive power droop coefficient, V 0 and Q 0 is the initial value of voltage and reactive power, where the reference value of the voltage q-axis component in reactive power droop control is 0; The AC voltage control is: in, is the d-axis component of the internal potential; is the q-axis component of the internal potential; , , and is the transfer function expression of AC voltage control in the complex domain.

[0007] Optionally, the phase difference The calculation formula is: in, is the internal potential phase angle; is the voltage phase angle at the port; is the d-axis component of the internal potential; is the q-axis component of the internal potential; The d-axis component of the voltage at the port; is the q-axis component of the voltage at the port.

[0008] Optionally, when the meshed SVG system is stable, the voltage q-axis control reference value of the meshed SVG system is set to 0 to operate the meshed SVG system.

[0009] Optionally, the AC voltage stability enhancement control is expressed as: let the voltage q-axis control reference value be: In the formula, K V is the coefficient of AC voltage enhancement control; is the phase angle difference; is the d-axis component of the internal potential; is the q-axis component of the internal potential; The d-axis component of the voltage at the port; is the q-axis component of the voltage at the port.

[0010] Optionally, the output current I The calculation formula is: in, I d is the d-axis component of the output current, I q is the q-axis component of the output current.

[0011] Optionally, judging whether the output current of the meshed SVG system reaches a preset current limit value further includes: If the output current is less than the current limit value, the grid-type SVG system is determined to be stable.

[0012] Optionally, the DC synchronous control of the meshed SVG system when it is stable is: in, The output phase of the DC voltage synchronous control is , port voltage phase The relationship is , ; The d-axis component of the voltage at the port; is the q-axis component of the voltage at the port; the DC voltage stability enhancement control when the grid-type SVG system is current saturated and there is a risk of instability is: In the formula, is the coefficient of DC voltage enhancement control; is the phase angle difference.

[0013] According to another aspect of the present invention, a grid-type SVG transient synchronous stability control device based on AC / DC voltage hybrid control is provided, comprising: A construction module, used to construct a DC voltage self-synchronization control module of a grid-forming SVG system; A calculation module, used for calculating the internal potential phase angle of the meshing type SVG system according to the operation parameter data of the meshing type SVG system based on the DC voltage self-synchronization control module; A judgment module is used to judge whether the phase angle difference between the phase angle at the port of the meshed SVG system and the internal potential phase angle is less than 2°, and if the phase angle difference is less than or equal to 2°, it is judged that the meshed SVG system is stable; The AC voltage control module is used to implement AC voltage stability enhancement control on the meshing type SVG system based on the DC voltage self-synchronization control module when the phase angle difference exceeds 2°, and calculate the output current of the meshing type SVG system; The DC voltage control module is used to determine whether the output current of the meshed SVG system reaches a preset current limit value. If the output current is greater than or equal to the current limit value, it is determined that the current of the meshed SVG system is saturated and there is a risk of instability, and DC voltage stability enhancement control is implemented on the meshed SVG system based on the DC voltage self-synchronization control module.

[0014] 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 described in any one of the above aspects of the present invention.

[0015] 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.

[0016] Therefore, the present invention proposes a control strategy for AC / DC voltage mixing based on the principle of adaptive power angle compensation, which can effectively improve the transient stability performance of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] A more complete understanding of exemplary embodiments of the present invention may be obtained by referring to the following drawings: Figure 1 It is a flow chart of a transient synchronous stability control method of a grid-type SVG based on AC / DC voltage hybrid control provided by an exemplary embodiment of the present invention; Figure 2It is another flow chart of a method for controlling transient synchronous stability of a grid-type SVG based on AC / DC voltage hybrid control provided by an exemplary embodiment of the present invention; Figure 3 Schematic diagram of a new energy delivery system including a network-type SVG provided by an exemplary embodiment of the present invention; Figure 4 is a control block diagram of a meshed SVG provided by an exemplary embodiment of the present invention; Figure 5 is a schematic diagram of an equivalent model of a new energy delivery system provided by an exemplary embodiment of the present invention; Figure 6 is a schematic diagram of a grid-following converter using LVRT provided by an exemplary embodiment of the present invention; Figure 7a and Figure 7b They are schematic diagrams of power angle characteristic curves of a combined transmission system before and after equivalent according to an exemplary embodiment of the present invention; Figure 8 is a schematic diagram of a power angle curve after considering the influence of DC capacitance provided by an exemplary embodiment of the present invention; Figure 9a , Figure 9b and Fig.9c They are schematic diagrams of a power angle waveform of a joint transmission system, an active power response waveform of a grid-type SVG, and an active power response waveform of a new energy device provided by an exemplary embodiment of the present invention; Fig.10a , Fig.10b and Fig.10c They are respectively a power angle waveform of a joint transmission system after improvement measures provided by an exemplary embodiment of the present invention, an active response waveform of a grid-type SVG, and a schematic diagram of an active response waveform of a new energy device; Fig.11a and Fig.11b They are respectively schematic diagrams of power angle instability of a combined transmission system provided by an exemplary embodiment of the present invention and waveforms of the combined transmission system after improvement measures are added; Fig.12a and Figure 12b They are respectively simulation comparison schematic diagrams of different control methods provided by an exemplary embodiment of the present invention; Fig.13 It is a structural schematic diagram of a grid-type SVG transient synchronous stability control device based on AC / DC voltage hybrid control provided by an exemplary embodiment of the present invention; Fig.14 This is a structure of an electronic device provided by an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] Exemplary Methods Figure 1 FIG. 1 is a flow chart of a method for analyzing and improving transient synchronization stability of a meshed SVG provided by an exemplary embodiment of the present invention. This embodiment can be applied to electronic devices, such as Figure 1 As shown, the transient synchronous stability analysis and improvement method 100 of the networked SVG includes the following steps: Step 101, constructing a DC voltage self-synchronization control module of a grid-forming SVG system; Step 102, calculating the internal potential phase angle of the meshed SVG system according to the operation parameter data of the meshed SVG system based on the DC voltage self-synchronous control module; Step 103, determining whether the phase angle difference between the phase angle at the port of the meshed SVG system and the internal potential phase angle is less than 2°, and determining that the meshed SVG system is stable when the phase angle difference is less than or equal to 2°; Step 104, when the phase angle difference exceeds 2°, performing AC voltage stability enhancement control on the meshing type SVG system based on the DC voltage self-synchronization control module, and calculating the output current of the meshing type SVG system; Step 105 determines whether the output current of the meshed SVG system reaches a preset current limit value. If the output current is greater than or equal to the current limit value, it is determined that the meshed SVG system is current saturated and there is a risk of instability, and DC voltage stability enhancement control is implemented on the meshed SVG system based on the DC voltage self-synchronization control module.

[0032] Specifically, the present invention aims to theoretically analyze the interaction between the grid-type SVG and the new energy base, reveal the transient instability mechanism of the grid-type SVG, and propose a stability-enhanced self-synchronization control strategy based on the principle of adaptive power angle compensation, which can effectively improve the transient stability performance of the system. Figure 2 As shown, the following steps are included: 1) Construct a DC voltage self-synchronization control module for a grid-type SVG system; 2) calculating the internal potential phase angle of the meshed SVG system according to the operation parameter data of the meshed SVG system, and calculating the phase angle at the port of the meshed SVG system and the phase angle difference of the internal potential phase angle; 3) determining whether the phase angle difference between the phase angle at the port of the meshed SVG system and the internal potential phase angle is less than a threshold value of 2°, and determining that the meshed SVG system is stable when the phase angle difference is less than 2°; 4) Calculate the current output by the meshed SVG system; 5) Determine the output current of the meshed SVG system I Whether the limit value is reached I max , if the output current is greater than or equal to I max When the phase angle difference is greater than 2°, it is determined that the grid-type SVG system is current saturated and has a risk of instability, and it is necessary to implement DC voltage stability enhancement control on the grid-type SVG.

[0033] Furthermore, the step 1) DC voltage self-synchronous control consists of DC synchronous control, reactive power droop control, and AC voltage control, wherein the DC synchronous control is expressed as: in, It is the output phase of DC voltage synchronous control, and is used for Parker transformation to convert the voltage and current of the abc three-phase into the dq coordinate system; is the DC voltage of SVG, It is the reference value of DC voltage control of SVG; T , J , D They are the proportional coefficient, inertia coefficient, and damping coefficient of DC voltage control; is the rated angular frequency, usually ; sis the Laplace operator.

[0034] Reactive power droop control is expressed as: in, V dref is the voltage d-axis component reference value, K Q is the reactive power droop coefficient, V 0 and Q 0 is the initial value of voltage and reactive power.

[0035] The reference value of the voltage q-axis component is 0.

[0036] The AC voltage control is: in is the d-axis component of the internal potential, is the q-axis component of the internal potential; , , and is the transfer function expression of AC voltage control in the complex domain.

[0037] Further, in step 2), the phase angle difference The calculation formula is: in, is the internal potential phase angle; is the voltage phase angle at the port; is the d-axis component of the internal potential, is the q-axis component of the internal potential; The d-axis component of the voltage at the port, is the q-axis component of the voltage at the port.

[0038] Furthermore, in step 3) When the voltage q-axis control reference value is

[0039] when When the voltage q-axis control reference value is In the formula, K V is the coefficient of AC voltage enhancement control.

[0040] Further, in step 4) outputting current I The calculation formula is: in, I d is the d-axis component of the output current, I qis the q-axis component of the output current.

[0041] like Then it is recorded as SVG current saturation, otherwise it is recorded as current unsaturation.

[0042] Furthermore, in step 5), if the current is not saturated or hour in, is the output phase of the DC voltage synchronous control, and its relationship with the internal potential and the port voltage phase is , ; is the DC voltage of SVG, It is the reference value of DC voltage control of SVG; T , J , D They are the proportional coefficient, inertia coefficient, and damping coefficient of DC voltage control; is the rated angular frequency, usually ; s is the Laplace operator.

[0043] When the current is saturated and In addition to the AC voltage stability enhancement control method, the DC voltage stability enhancement control method needs to be started to adjust the output of the DC voltage synchronous control, which is expressed as in is the coefficient of DC voltage enhancement control.

[0044] Specific verification embodiment of the present invention: In Matlab software, we create Figure 3 The simulation model shown in Figure 1 is shown in Figure 12. Among them, the power grid model adopts an ideal three-phase voltage source with a fixed voltage amplitude and frequency of 1p.u. and 50HZ. The grid-forming SVG adopts Figure 4 The control structure shown in the figure, the equivalent model of the new energy delivery system is as follows Figure 5 As shown, new energy stations use Figure 6 The grid-following converter shown is shown. X g , X s and X v is the corresponding branch reactance, E s and δ s is the amplitude and phase of the transient electromotive force of the network-type SVG, U v , U p and δv , δ p They are the amplitude and phase of the bus voltage at the new energy station and the collection point respectively. X F is the filter inductance of the device, C F is a filter capacitor, and the control consists of “power droop-voltage control loop-current control loop”. The specific parameters used in the simulation are shown in Table 1.

[0045] Table 1 Parameter values ​​of the system in the simulation verification of the embodiment

[0046] Figure 7a and Figure 7b The power angle curves of the combined transmission system before and after the equivalent are verified by simulation in the embodiment of the present invention. Figure 7a and Figure 7b It can be seen that due to the active power injected by the new energy, the sinusoidal power angle curve P es Distortion occurs, which causes trouble for the stability analysis of the system. Through equivalent modeling, the electromagnetic power of the joint transmission system can be always positive, which is helpful for understanding and further analysis.

[0047] Figure 8 In order to consider the impact of DC capacitor dynamics on the transient synchronization stability of the system, the equivalent power angle curve of the system output is jointly sent. P E < P S From the dynamic equation of DC capacitor, we know that DC capacitor will absorb energy and cause DC voltage V DC Considering the voltage resistance of the capacitor, the general setting V DC The maximum voltage that can be achieved is 1.1 to 1.15 times the rated voltage. When the voltage on both sides of the capacitor exceeds this value, the energy-consuming element starts to consume excess energy and keep the DC voltage constant, thereby achieving the purpose of protecting the equipment. DC Increase to the critical value, that is P eqe_c In the most serious drop situation, the DC capacitor has the most serious impact on the system stability. The acceleration area of ​​the equivalent system changes from A1 to A1+A2, and the deceleration area changes from D1+D2 to D1. It is easier for the system to cross the stable equilibrium point.

[0048] Figure 9a~Figure 9cTo verify the waveform diagram of the power angle stability characteristics of the combined transmission system, it can be seen from the figure that when the active power provided by the renewable energy is large before the fault occurs, the risk of active angle instability of the combined transmission system is increased, and the active power obtained by the grid-type SVG during the fault becomes negative, and its absolute value is basically the same as the active power output of the renewable energy.

[0049] Figure 10a~Figure 10c After adopting the improvement measures, the system is in different K θ The power angle curve under the control of the system and the waveform of each variable. It can be seen that the proposed control strategy reduces P meqf , which reduces the acceleration area of ​​the system in disguise, and improves the transient stability performance of the system.

[0050] also, Fig.11a and Fig.11b The hardware simulation based on RT-LAB can also illustrate the correctness of the mechanism analysis and the effectiveness of the improvement measures.

[0051] In order to further verify the superiority of the improvement measures proposed in this paper, Fig.12a For U: 1.0pu→0.5pu, Figure 12b Figure 2 is a schematic diagram of simulation results under different control modes for U: 1.0pu→0p.u. Table 2 shows the waveforms and critical removal times corresponding to different improvement measures under different voltage drop levels.

[0052] Table 2 Limit removal time under different fault conditions

[0053] Therefore, the present invention proposes an AC / DC voltage hybrid control strategy based on the principle of adaptive power angle compensation, which can effectively improve the transient stability performance of the system. It can ensure that the grid-type SVG can alleviate the transient instability problem caused by power imbalance in transient state, improve the transient stability margin of the system, and compared with other improvement measures, the proposed control strategy can ensure the transient stability performance of the power grid under more serious faults.

[0054] Exemplary Devices Fig.13 Schematic diagram of the structure of a network-type SVG transient synchronous stability analysis and promotion device provided by an exemplary embodiment of the present invention. Fig.13 As shown, the apparatus 1300 includes: A construction module 1310 is used to construct a DC voltage self-synchronization control module of a grid-forming SVG system; A calculation module 1320, configured to calculate the internal potential phase angle of the meshed SVG system according to the operation parameter data of the meshed SVG system based on the DC voltage self-synchronization control module; A judgment module 1330 is used to judge whether the phase angle difference between the phase angle at the port of the meshed SVG system and the internal potential phase angle is less than 2°, and if the phase angle difference is less than or equal to 2°, it is determined that the meshed SVG system is stable; The AC voltage control module 1340 is used to implement AC voltage stability enhancement control on the meshing type SVG system based on the DC voltage self-synchronization control module when the phase angle difference exceeds 2°, and calculate the output current of the meshing type SVG system; The DC voltage control module 1350 is used to determine whether the output current of the meshed SVG system reaches a preset current limit value. If the output current is greater than or equal to the current limit value, it is determined that the current of the meshed SVG system is saturated and there is a risk of instability, and DC voltage stability enhancement control is implemented on the meshed SVG system based on the DC voltage self-synchronization control module.

[0055] Optionally, the DC voltage self-synchronous control module is composed of DC synchronous control, reactive power droop control and AC voltage control, wherein the DC synchronous control is expressed as: In the formula, Output phase for synchronous control of DC voltage; is the DC voltage of SVG, It is the reference value of DC voltage control of SVG; T , J , D They are the proportional coefficient, inertia coefficient, and damping coefficient of DC voltage control; is the rated angular frequency; s is the Laplace operator; Reactive power droop control is expressed as: In the formula, V dref is the voltage d-axis component reference value, K Q is the reactive power droop coefficient, V 0 and Q 0 is the initial value of voltage and reactive power, where the reference value of the voltage q-axis component in reactive power droop control is 0; The AC voltage control is: in, is the d-axis component of the internal potential; is the q-axis component of the internal potential; , , and is the transfer function expression of AC voltage control in the complex domain.

[0056] Optionally, the phase difference The calculation formula is: in, is the internal potential phase angle; is the voltage phase angle at the port; is the d-axis component of the internal potential; is the q-axis component of the internal potential; The d-axis component of the voltage at the port; is the q-axis component of the voltage at the port.

[0057] Optionally, when the meshed SVG system is stable, the voltage q-axis control reference value of the meshed SVG system is set to 0 to operate the meshed SVG system.

[0058] Optionally, the AC voltage stability enhancement control is expressed as: let the voltage q-axis control reference value be: In the formula, K V is the coefficient of AC voltage enhancement control; is the phase angle difference; is the d-axis component of the internal potential; is the q-axis component of the internal potential; The d-axis component of the voltage at the port; is the q-axis component of the voltage at the port.

[0059] Optionally, the output current I The calculation formula is: in, I d is the d-axis component of the output current, I q is the q-axis component of the output current.

[0060] Optionally, judging whether the output current of the meshed SVG system reaches a preset current limit value further includes: If the output current is less than the current limit value, the grid-type SVG system is determined to be stable.

[0061] Optionally, the DC synchronous control of the meshed SVG system when it is stable is: in, The output phase of the DC voltage synchronous control is , port voltage phase The relationship is , ; The d-axis component of the voltage at the port; is the q-axis component of the voltage at the port; The DC voltage stability enhancement control when the grid-type SVG system is current saturated and has the risk of instability is: In the formula, is the coefficient of DC voltage enhancement control; is the phase angle difference.

[0062] Exemplary Electronic Devices Fig.14 This is a structure of an electronic device provided by an exemplary embodiment of the present invention. Fig.14 As shown, the electronic device 140 includes one or more processors 141 and a memory 142 .

[0063] The processor 141 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.

[0064] The memory 142 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, a random access memory (RAM) and / or a cache memory (cache), etc. The non-volatile memory may include, for example, a read-only memory (ROM), a hard disk, a flash memory, etc. One or more computer program instructions may be stored on the computer-readable storage medium, and the processor 141 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 143 and an output device 144, which are interconnected via a bus system and / or other forms of connection mechanisms (not shown).

[0065] In addition, the input device 143 may also include, for example, a keyboard, a mouse, etc.

[0066] The output device 144 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.

[0067] Of course, to simplify, Fig.14 Only 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.

[0068] Exemplary computer program products and computer-readable storage media 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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 transient synchronous stability control method for a grid-type SVG based on AC / DC voltage hybrid control, characterized in that: include: Construct a DC voltage self-synchronization control module for a grid-type SVG system; Calculating the internal potential phase angle of the meshed SVG system according to the operating parameter data of the meshed SVG system based on the DC voltage self-synchronous control module; Determine whether the phase angle difference between the phase angle at the port of the meshed SVG system and the internal potential phase angle is less than 2°, and determine that the meshed SVG system is stable when the phase angle difference is less than or equal to 2°; When the phase angle difference exceeds 2°, performing AC voltage stability enhancement control on the meshing type SVG system based on the DC voltage self-synchronization control module, and calculating the output current of the meshing type SVG system; Determine whether the output current of the meshed SVG system reaches a preset current limit value; if the output current is greater than or equal to the current limit value, determine that the meshed SVG system is current saturated and has a risk of instability; and implement DC voltage stability enhancement control on the meshed SVG system based on the DC voltage self-synchronization control module.

2. The method according to claim 1, characterized in that: The DC voltage self-synchronous control module is composed of DC synchronization control, reactive power droop control and AC voltage control, wherein the DC synchronization control is expressed as: In the formula, Output phase for synchronous control of DC voltage; is the DC voltage of SVG, It is the reference value of DC voltage control of SVG; T , J , D They are the proportional coefficient, inertia coefficient, and damping coefficient of DC voltage control; is the rated angular frequency; s is the Laplace operator; The reactive power droop control is expressed as: In the formula, V dref is the voltage d-axis component reference value, K Q is the reactive power droop coefficient, V 0 and Q 0 is the initial value of voltage and the initial value of reactive power, wherein the reference value of the voltage q-axis component in the reactive power droop control is 0; The AC voltage control is: in, is the d-axis component of the internal potential; is the q-axis component of the internal potential; , , and is the transfer function expression of AC voltage control in the complex domain.

3. The method according to claim 1, characterized in that The phase angle difference The calculation formula is: in, is the internal potential phase angle; is the voltage phase angle at the port; is the d-axis component of the internal potential; is the q-axis component of the internal potential; The d-axis component of the voltage at the port; is the q-axis component of the voltage at the port.

4. The method according to claim 1, characterized in that: When the meshed SVG system is stable, the voltage q-axis control reference value of the meshed SVG system is set to 0 to operate the meshed SVG system.

5. The method according to claim 1, characterized in that: The AC voltage stability enhancement control is expressed as follows: let the voltage q-axis control reference value be: In the formula, K V is the coefficient of AC voltage enhancement control; is the phase angle difference; is the d-axis component of the internal potential; is the q-axis component of the internal potential; The d-axis component of the voltage at the port; is the q-axis component of the voltage at the port.

6. The method according to claim 1, characterized in that Output Current I The calculation formula is: in, I d is the d-axis component of the output current, I q is the q-axis component of the output current.

7. The method according to claim 1, characterized in that Determining whether the output current of the grid-type SVG system reaches a preset current limit value also includes: If the output current is less than the current limit value, it is determined that the meshed SVG system is stable.

8. The method according to claim 2, characterized in that: The DC synchronous control of the grid-type SVG system when it is stable is: in, The output phase of the DC voltage synchronous control is , port voltage phase The relationship is , ; The d-axis component of the voltage at the port; is the q-axis component of the voltage at the port; The DC voltage stability enhancement control when the grid-type SVG system is current saturated and has the risk of instability is as follows: In the formula, is the coefficient of DC voltage enhancement control; is the phase angle difference.

9. A grid-type SVG transient synchronous stability control device based on AC / DC voltage hybrid control, characterized in that: include: A construction module, used to construct a DC voltage self-synchronization control module of a grid-forming SVG system; A calculation module, used for calculating the internal potential phase angle of the meshed SVG system according to the operation parameter data of the meshed SVG system based on the DC voltage self-synchronization control module; A judgment module, used to judge whether the phase angle difference between the phase angle at the port of the meshed SVG system and the internal potential phase angle is less than 2°, and if the phase angle difference is less than or equal to 2°, judge that the meshed SVG system is stable; an AC voltage control module, configured to implement AC voltage stability enhancement control on the meshing type SVG system based on the DC voltage self-synchronization control module when the phase angle difference exceeds 2°, and calculate the output current of the meshing type SVG system; A DC voltage control module is used to determine whether the output current of the meshed SVG system reaches a preset current limit value. If the output current is greater than or equal to the current limit value, it is determined that the current of the meshed SVG system is saturated and there is a risk of instability, and DC voltage stability enhancement control is implemented on the meshed SVG system based on the DC voltage self-synchronization control module.

10. 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 8.

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