Event-triggered distributed secondary control method and system for grid-forming virtual synchronous machine

Abstract

The application discloses a kind of network type virtual synchronous machine distributed secondary control method and system based on event triggering, it is related to microgrid secondary control technical field, method includes: constructing island microgrid dynamic model;Event-triggered controller is introduced, event-triggered mechanism is deeply fused with time-varying gain control, and current error exceeds preset threshold when triggering communication by dynamic threshold function and non-periodic communication strategy;By constraining error dynamic change rate and setting error lower bound after triggering, ensure that event-triggered interval exists positive lower bound, to exclude Zeno phenomenon.Event-triggered mechanism is deeply fused with predetermined time control, while guaranteeing frequency recovery and power distribution accuracy by dynamic threshold function and non-periodic communication strategy, significantly reduce communication burden, and exclude Zeno phenomenon.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of micro-grid secondary control technology, and particularly relates to a network-structured virtual synchronous machine distributed secondary control method and system based on event triggering. BACKGROUND

[0002] With the increasing penetration of new energy, island micro-grid has become an important solution for power supply in remote areas due to its independent operation capability. The virtual synchronous machine technology significantly improves the stability of power electronic devices in the micro-grid by simulating the inertia and damping characteristics of the traditional synchronous generator. However, the primary control of the virtual synchronous machine will cause a frequency deviation, which needs to be eliminated by secondary control to achieve accurate power distribution. At present, the mainstream secondary control strategies include centralized, decentralized and distributed control, among which the distributed control is highly concerned due to its high robustness and good flexibility.

[0003] The existing distributed secondary control adopts a periodic communication mechanism, that is, the controllers continuously exchange information to achieve consistency. However, periodic communication has the following significant defects: 1) waste of communication resources: when the system is in steady state, frequent communication leads to redundant data transmission, occupying bandwidth and increasing communication cost; 2) insufficient real-time performance: high-frequency communication may reduce the control response speed due to network delay or congestion; 3) security risks: continuous communication is vulnerable to malicious attacks, threatening the information security of the system. To reduce the communication burden, the event-triggering mechanism is introduced into the field of micro-grid control. The event-triggering mechanism will determine whether the system communicates at each sampling time according to the occurrence of the event triggered by the condition. The basic principle is to add an event detector and a trigger between the sensors and controllers of each VSG in the island micro-grid. The event detector collects the necessary measurement data at each sampling time and determines whether the current value meets the event triggering condition through calculation. If the triggering condition is met, the trigger will immediately act to make the neighboring nodes communicate and update the controller signal, thereby completing an event triggering. Otherwise, if the triggering condition is not met, the trigger remains static and the controller signal is not updated. Therefore, the event detection link plays a core role in the entire event-triggering mechanism. Although existing researches have verified the feasibility of event triggering in micro-grid, there are still the following problems: 1) complex triggering condition design: most methods need to rely on global information or complex threshold functions, which are difficult to implement; 2) risk of Zeno phenomenon: if the event is triggered infinitely many times in a finite time, the event-triggering mechanism will fail, and the system may collapse due to frequent communication; 3) insufficient combination with predetermined time control: most existing event-triggering strategies are for limited time or fixed time control, and do not fully utilize the global convergence characteristics of the predetermined time control, resulting in uncertain disturbance recovery time.

[0004] In summary, the prior art is difficult to reduce the communication volume while taking into account the system dynamic performance and stability. Therefore, there is an urgent need for an efficient and secure distributed secondary control method that can achieve frequency recovery and power distribution within a predetermined time, and significantly reduce communication burden through an event-triggered mechanism. SUMMARY

[0005] The purpose of the present application is to provide an event-triggered network-based virtual synchronous machine distributed secondary control method and system, which addresses the communication redundancy, insufficient dynamic performance and Zeno phenomenon risk of the existing island microgrid distributed secondary control, deeply integrates the event-triggered mechanism and the predetermined time control, and through a dynamic threshold function and a non-periodic communication strategy, significantly reduces the communication burden while ensuring the accuracy of frequency recovery and power distribution, and eliminates the Zeno phenomenon.

[0006] The present application provides an event-triggered network-based virtual synchronous machine distributed secondary control method, comprising:

[0007] Building an island microgrid dynamic model;

[0008] Introducing an event-triggered controller, deeply integrating the event-triggered mechanism and the time-varying gain control, triggering communication through a dynamic threshold function and a non-periodic communication strategy when the current error exceeds the preset threshold;

[0009] By constraining the error dynamic change rate and setting the error lower bound after triggering, it is ensured that the event-triggered interval has a positive lower bound, thereby eliminating the Zeno phenomenon.

[0010] As a preferred, the building an island microgrid dynamic model includes an island microgrid of N virtual synchronous machines (VSGs), and the rotor motion equation of the i-th VSG is as follows:

[0011] ,

[0012] Wherein, J i is the virtual inertia; D i is the damping coefficient; ω i is the output angular frequency; P i is the output active power; P ref，i is the reference active power; ω N is the rated frequency; is the event-triggered control input.

[0013] As a preferred,

[0014] Only at moment is updated, and remains unchanged within interval, that is:

[0015] ,

[0016] where, is the kth event-triggering time, is the k+1th event-triggering time, is the secondary control input signal, is the event-triggered control input signal.

[0017] As preferred, the deep integration of event-triggering mechanism and time-varying gain control includes:

[0018] configuring the secondary control input signal ,

[0019] where, , is a predetermined time-varying gain function, is the error signal under event-triggering condition, i、 a j is a parameter for controlling accurate active power allocation, ij is an adjacency matrix element, indicating whether i and j have communication or not, i is the gain coefficient corresponding to the ith DG, used to adjust the influence of control input error e ui on the overall error, i represents the neighbor set of DG i , j represents the neighbor DG i of DG j .

[0020] As preferred, the introduction of event-triggered controller includes:

[0021] setting the first DG in the distributed communication structure as the leader, setting u ref as the control input variable transmitted by the first DG leader, providing the reference signal of the control input, providing the reference signal for the DGs other than the first DG leader, defining e ui as:

[0022] ,

[0023] defining the event-triggered control input and the error of continuous control input u i (t) as:

[0024] ,

[0025] triggering time is determined by the following condition:

[0026] ,

[0027] wherein, is a triggering sensitivity parameter for controlling triggering frequency; is a design parameter, satisfying , is an adjustment parameter, g i is a DG i corresponding gain coefficient, N i is a number of neighbor nodes, e is a consistency error, satisfying e = u i - u ref , t is a real-time time;

[0028] is kept constant in a triggering interval, satisfying:

[0029] .

[0030] As preferred, the time-varying gain control is calculated as follows:

[0031] ,

[0032] wherein, , is a time-varying gain function, is a preset time-varying function, b and c are gain coefficients, is a user-defined function, is a preset finite time allowed by physics, the recovery duration is set by setting the value of , n is a constant, satisfying , t0 is a preset time at which the second control starts to act.

[0033] As preferred, the ensuring that the event triggering interval has a positive lower bound by constraining the dynamic change rate of the error and setting a lower bound of the error after triggering includes:

[0034] DG i has not received an update of the state of a neighbor node, and triggering occurs at , then ;

[0035] has not been triggered, and from the sampling error, it can be seen that:

[0036] ,

[0037] from t to integration: ,

[0038] wherein, e i is ui The proportional error of the ratio, combined with the trigger condition, is calculated as follows:

[0039] .

[0040] The application also provides an event-triggered network-constructed virtual synchronous machine distributed secondary control system, comprising:

[0041] A model construction module is configured to construct an island micro-grid dynamic model.

[0042] A deep fusion module is configured to introduce an event-triggered controller, deeply fuse the event-triggering mechanism and the time-varying gain control, and trigger communication through a dynamic threshold function and a non-periodic communication strategy when the current error exceeds a preset threshold.

[0043] An anti-Zeno module is configured to constrain the error dynamic change rate and set a lower bound of the error after triggering, so as to ensure that there is a positive lower bound of the event-triggering interval, thereby eliminating the Zeno phenomenon.

[0044] Preferably, the island micro-grid dynamic model comprises N virtual synchronous machines (VSGs) in an island micro-grid, and the rotor motion equation of the i-th VSG is as follows:

[0045] ,

[0046] wherein, J i is a virtual inertia; D i is a damping coefficient; ω i is an output angular frequency; P i is an output active power; P ref，i is a reference active power; ω N is a rated frequency; and is an event-triggered control input.

[0047] The application also provides an electronic device, comprising:

[0048] A memory is configured to store a processing program.

[0049] A processor is configured to implement the event-triggered network-constructed virtual synchronous machine distributed secondary control method according to the embodiments of the application when executing the processing program.

[0050] The application also provides a computer readable storage medium configured to store computer instructions, which are executed by a processor to complete the event-triggered network-constructed virtual synchronous machine distributed secondary control method according to the embodiments of the application.

[0051] Compared with the prior art, the application has the following beneficial effects:

[0052] This invention proposes a distributed secondary control method for a network-based virtual synchronous machine based on event triggering, which solves the communication redundancy problem caused by traditional continuous periodic sampling and improves the system's communication efficiency and stability. Building upon time-distributed control, an event triggering mechanism is introduced, triggering communication only when the system state error exceeds a preset threshold, avoiding the resource waste of periodic communication. By defining the control input error and sampling error, event triggering conditions suitable for leader-follower communication structures are designed, setting the triggering mechanism only for the follower DG, further reducing communication volume. Using Lyapunov function analysis, system stability is demonstrated, proving that this mechanism can effectively eliminate the Zeno phenomenon and ensure a limited number of triggers within a finite time.

[0053] Compared with existing technologies, this method significantly reduces communication frequency while ensuring frequency recovery and precise power allocation within a predetermined time. Simulation experiments show that under load surges and plug-and-play scenarios, the system frequency can quickly converge to 50Hz, active power is allocated according to a preset ratio, and the number of triggers is reduced by approximately 60% compared to the traditional continuous communication mode, effectively saving communication resources and improving the system's economy and reliability. This research provides an effective solution for the stable operation of isolated microgrids in communication-constrained scenarios. Attached Figure Description

[0054] Figure 1 This is a flowchart of the distributed secondary control method for a network-based virtual synchronous machine based on event triggering in an embodiment of the present invention;

[0055] Figure 2 This is the communication topology of the islanded microgrid in this embodiment of the invention;

[0056] Figure 3 This is a structural diagram of the event triggering controller in an embodiment of the present invention;

[0057] Figures 4-5 To illustrate this invention, frequency waveforms before and after the event is triggered are added to the embodiments of the present invention.

[0058] Figures 6-7 This is a waveform diagram of frequency and power response under a sudden load change scenario in an embodiment of the present invention;

[0059] Figure 8 This is a waveform diagram of frequency and power response in a plug-and-play scenario according to an embodiment of the present invention. Detailed Implementation

[0060] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0061] The term "comprising" and variations thereof as used herein are open-ended, and mean "including but not limited to". The term "based on" means "based, at least in part, on". The term "one embodiment" means "at least one embodiment". The term "another embodiment" means "at least one additional embodiment". The term "some embodiments" means "at least some embodiments". Related definitions are given throughout the description.

[0062] It should be noted that the terms "one", "second", and the like mentioned in the present application disclosure are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.

[0063] It should be noted that the modification of "one" or "multiple" mentioned in the present application disclosure is illustrative but not restrictive, and those skilled in the art should understand that, unless otherwise explicitly indicated in the context, it should be understood as "one or more".

[0064] As shown in Figure 1 The present application provides an event-triggered network-based virtual synchronous machine distributed secondary control method, which comprises the following steps:

[0065] S1: Constructing an island microgrid dynamic model;

[0066] S2: Introducing an event-triggered controller, deeply integrating the event-triggering mechanism with the time-varying gain control, triggering communication through a dynamic threshold function and a non-periodic communication strategy when the current error exceeds a preset threshold;

[0067] S3: By constraining the dynamic change rate of error and setting the lower bound of error after triggering, ensuring that the event-triggering interval has a positive lower bound, thereby excluding the Zeno phenomenon.

[0068] The event triggering mechanism adopted in the embodiment triggers communication only when the error exceeds the dynamic threshold, avoids the redundancy of periodic communication, significantly reduces the communication frequency between nodes in the distributed system, and is particularly suitable for the island micro-grid environment with limited communication resources. The non-periodic communication strategy breaks the fixed time communication mode, further optimizes the communication opportunity, reduces the network load and delay, and improves the real-time performance of the system. The pre-determined time-varying gain function dynamically adjusts the control input strength, accelerates the error convergence, and ensures that the system reaches a stable state within a preset time. The triggering threshold is adjusted adaptively according to the system state, balancing the control accuracy and communication frequency, and avoiding excessive conservatism or frequent triggering. By limiting the error change rate, a positive lower bound is ensured between two triggering intervals, theoretically eliminating the possibility of infinite triggering, avoiding continuous triggering caused by instantaneous error zero, and ensuring the practical feasibility of the triggering interval. The scheme combines the event triggering mechanism and the time-varying gain control, significantly reduces the communication cost while ensuring the control performance, and eliminates the Zeno phenomenon through strict theoretical constraints, ultimately realizing the efficient, stable and robust operation of the island micro-grid. It provides a lightweight and practical solution for the distributed virtual synchronous machine coordination control.

[0069] In an embodiment, the step S1 of constructing the dynamic model of the island micro-grid includes an island micro-grid with N virtual synchronous machines (VSGs), and the rotor motion equation of the i-th VSG is as follows:

[0070] ,

[0071] where J i is the virtual inertia; D i is the damping coefficient; ω i is the output angular frequency; P i is the output active power; P ref，i is the reference active power; ω N is the rated frequency, f N = 50 Hz; is the event-triggered control input signal, which simulates the inertia and damping of the traditional synchronous generator through the virtual inertia J i and the damping coefficient D i , provides frequency support when the load is disturbed, suppresses frequency fluctuations, and improves the transient stability of the island micro-grid. Based on the rotor motion equation, the output active power P i is realized to quickly track the reference value P ref,i and maintain power balance.

[0072] is the rewriting of the quadratic control input signal , which is updated only at , and is updated at The interval remains unchanged, i.e.:

[0073] ,

[0074] wherein, is the kth event-triggering moment, is the k+1th event-triggering moment, is the secondary control input signal, is the event-triggering control input signal, indicating that the event-triggering control input signal will remain the value at the previous moment before the second triggering, avoiding periodic communication and continuous calculation, significantly reducing the communication frequency between distributed VSGs and the controller calculation burden, breaking the fixed-time communication mode, triggering the control signal update only when the error exceeds the dynamic threshold, optimizing the utilization rate of communication resources, and being particularly suitable for communication-limited island microgrids.

[0075] In an embodiment, the step S2 of deeply integrating the event-triggering mechanism with the time-varying gain control includes:

[0076] configuring the secondary control input signal ,

[0077] wherein, , is a predetermined time-varying gain function, is an error signal under event-triggering condition, a i , a j is a parameter for controlling accurate active power distribution, a ij is an adjacency matrix element, indicating whether i and j have communication or not, g i is a gain coefficient corresponding to the ith DG, used to adjust the influence degree of the control input error e ui on the overall error, N i represents the neighbor set of the DG i , and j represents the neighbor DG i of the DG j . By using the adjacency matrix element a ij and the neighbor set N i , the coordinated distribution of active power among DGs is realized based on local communication, and the power balance of the microgrid is maintained. By using the parameters a i , a j and the gain coefficient g i , the control weights of each DG are flexibly adjusted, the tracking error and the accuracy of power distribution are balanced, and local oscillation is avoided. Based on the distributed control strategy of neighbor state, there is no need for centralized decision-making, and single node failure does not affect global operation, thereby improving system reliability.

[0078] The step S2 of introducing the event-triggering controller specifically includes the following steps:

[0079] In the distributed communication structure, the first DG is designated as the leader, and u is set... ref The first DG leader transmits control input variables and provides a reference signal for control inputs. It also provides a reference signal for all DGs except the first leader. This can be understood as only the first DG setting a global reference u. ref Other DGs will follow this reference and gradually approach it. The leader-distributed structure here is essentially designed to reduce communication; it doesn't require sharing the global reference u. ref Transmitted to each DG.

[0080] Define e ui for:

[0081] ,

[0082] Define event trigger control input With continuous control input u i The error of (t) is:

[0083] ,

[0084] Triggering time It is determined by the following conditions:

[0085] ,

[0086] in, This is a trigger sensitivity parameter used to control the trigger frequency; For design parameters, satisfy , To adjust the parameters, g i For DG i The corresponding gain coefficient, N i Let u be the number of neighboring nodes, e be the consistency error, and satisfy e = u. i -u ref t is the real-time time;

[0087] It remains constant within the trigger interval, satisfying:

[0088] .

[0089] Those skilled in the art will understand that the above triggering rule is triggered when the current error is greater than the sampling error, i.e., the error exceeds the threshold. i Otherwise, keep the previous u i Without changing, the event triggering mechanism is deeply integrated with the predetermined time control, and the frequency recovery and power allocation accuracy are guaranteed through dynamic threshold functions and aperiodic communication strategies.

[0090] In one embodiment, the time-varying gain control is calculated as follows:

[0091] ,

[0092] wherein, , is a time-varying gain function, is a preset time-varying function, and b and c are gain coefficients, is a user-defined function, is a preset finite time allowed by physics, and the recovery time is set by setting the value of n, is a constant, and satisfies t0is a preset time at which the secondary control starts to act.

[0093] Once the Zeno phenomenon occurs, the triggering mechanism will fail. In order to rule out the Zeno phenomenon, it is necessary to prove that there is a time lower bound > 0 between any two departure intervals, that is, according to the definition of event triggering, the designed event triggering mechanism needs to ensure that there is no infinite triggering in a finite time, so it is necessary to prove that there is a time lower bound between any two event intervals, which can rule out the Zeno phenomenon. In step S3, the error dynamic change rate is constrained and the error lower bound after triggering is set to ensure that there is a positive lower bound between event triggering intervals, that is, the time interval between two triggering events must be greater than a fixed positive number, that is, there is a minimum time interval > 0, which cannot tend to zero infinitely, and specifically includes:

[0094] In the case that DG i does not receive an update of the state of the neighbor node, and triggering occurs at ; ;

[0095] If no new triggering is performed at t, it can be known from the sampling error that:

[0096] ,

[0097] From t to integration is obtained: ,

[0098] wherein e i is the proportional error of u i , and the triggering condition is calculated to obtain:

[0099] ,

[0100] wherein, is the proportional error after event triggering, and it can be obtained by rearrangement:

[0101] , i.e. the error always has a lower bound, and after each trigger, the error cannot tend to 0 infinitely, and the Zeno phenomenon can be ruled out.

[0102] The embodiment proposes a distributed secondary control strategy based on event triggering for island microgrid with virtual synchronous machines, aiming to solve the communication redundancy problem caused by traditional continuous periodic sampling and improve the communication efficiency and stability of the system. On the basis of time-distributed control, an event-triggering mechanism is introduced, which only triggers communication when the system state error exceeds the preset threshold, avoiding the waste of resources caused by periodic communication. By defining the control input error and sampling error, an event-triggering condition suitable for the leader-follower communication structure is designed, and the triggering mechanism is only set for the follower DG, further reducing the communication volume. With the help of Lyapunov function analysis, the stability of the system is analyzed, and it is proved that the mechanism can effectively rule out the Zeno phenomenon and ensure a limited number of triggers within a limited time. Compared with the prior art, the method significantly reduces the communication frequency while ensuring the frequency recovery and accurate power allocation within the predetermined time. Simulation experiments show that under the load mutation and plug-and-play scenarios, the system frequency can quickly converge to 50Hz, the active power is allocated according to the preset proportion, and the number of triggers is reduced by about 60% compared with the traditional continuous communication mode, effectively saving communication resources and improving the economy and reliability of the system. The research provides an effective solution for the stable operation of island microgrid in communication-limited scenarios.

[0103] In order to verify the actual control effect of the proposed time-triggering mechanism, a communication topology as shown in FIG. 2 is used for verification simulation, Figure 2 FIG. 3 is a structure diagram of the event-triggering controller, and Table 1 shows the inverter and bottom controller parameters of the four DGs as follows: Figure 3

[0104] Table 1 Inverter control parameters

[0105]

[0106] In all experiments, DG1 is the leader and triggers the remaining three DG units, and load mutation and plug-and-play tests are performed. The active power allocation ratio is set to P1:P2:P3:P4=1:2:1:2. The total simulation time is 4s, and the predetermined recovery time is set to 0.5s. The reference frequency is set to 50Hz.

[0107] The embodiment is a microgrid consisting of four virtual synchronous machines for island operation. At the beginning of the simulation, only the primary control works. At t=1s, the distributed event-triggering secondary control based on the predetermined time is connected; at t=2s, the device DG4 is switched on and the load mutation test is performed; at t=3s, the device is disconnected and the load mutation test is performed.​

[0108] Figures 4-5 The frequency waveforms before and after the event-triggered secondary control method is added are represented respectively. By comparison, it can be seen that the effect of the predetermined time recovery is unchanged, the system frequency is recovered within the set 0.5s, but due to the addition of the event-triggered control, the original predetermined time control system parameters need to be expanded according to the actual situation to achieve the predetermined time control effect.

[0109] Further, the performance of the control strategy proposed in the application is further verified in the load mutation scenario. Figures 6-7 The frequency and power response waveform of the event-triggered control strategy is given, and Table 2 gives the event-triggering times of the DG under the load change condition as follows:

[0110] Table 2 Event-triggering times of DG in load mutation scenario

[0111]

[0112] The predetermined time is set to 0.5s. Before 1s, the system works only under the action of the first control, and the event-triggered secondary control is started at 1s, from Figure 6 It can be seen that the frequency is restored to the reference value f ref =50Hz at 1.5s, the active power distribution ratio is accurately distributed according to the set ratio P1:P2:P3:P4=1:2:1:2 within 0.5s, the predetermined time control can be realized, and the frequency recovery and accurate distribution of active power are realized. In the process of connecting and disconnecting the load at 2s and 3s, the output frequency and active power of the island microgrid can be stabilized at the reference value under the setting of the predetermined time, and the active power is distributed according to the new load capacity with P1:P2:P3:P4=1:2:1:2, so the designed control strategy is effective in the case of load mutation.

[0113] Finally, in the plug-and-play scenario, the connection between DG4 and the microgrid system is disconnected, simulating the situation of equipment being put into and disconnected, as shown in Figure 8 The secondary control is started at 1s, the frequency and power respond quickly, DG4 is disconnected at 2s, the secondary controller can be restored to 50Hz within the set 0.5s and maintained, the power is redistributed according to the preset P1:P2:P3:P4=1:2:1:2, and the system still works normally at 3s, which means that the control objectives of frequency recovery and accurate power distribution are completed, and the preset event distributed secondary control still acts on the system in the global range. The triggering times of all DGs are listed in Table 3 as follows:

[0114] Table 3 Event-triggering times of DG in plug-and-play scenario

[0115]

[0116] The results show that the proposed event triggering mechanism has good plug-and-play characteristics, and can flexibly cope with device and load switching during system operation, ensuring the stability and reliability of the system.

[0117] Therefore, the embodiment of the present application adopts the above-mentioned event-triggered distributed secondary control method of the virtual synchronous machine of the island micro-grid, and uses limited aperiodic communication to reduce the communication burden of the system. Under the event triggering mechanism, the distributed control strategy will be affected. The mechanism starts to trigger communication when the system is disturbed, thereby effectively reducing the communication redundancy caused by disturbance and improving the communication efficiency and overall performance of the system within a predetermined time.

[0118] Based on the same concept, the present application provides an event-triggered network-based virtual synchronous machine distributed secondary control system, comprising:

[0119] a model construction module for constructing an island micro-grid dynamic model;

[0120] a deep fusion module for introducing an event-triggered controller, deeply fusing the event triggering mechanism and the time-varying gain control, and triggering communication through a dynamic threshold function and a non-periodic communication strategy when the current error exceeds the preset threshold;

[0121] a Zeno-resistant module for constraining the dynamic change rate of the error and setting the lower bound of the error after triggering, ensuring that the event triggering interval has a positive lower bound, thereby eliminating the Zeno phenomenon.

[0122] The construction of the island micro-grid dynamic model includes an island micro-grid with N virtual synchronous machines (VSGs), and the rotor motion equation of the i-th VSG is as follows:

[0123] ,

[0124] wherein J i is the virtual inertia; D i is the damping coefficient; ω i is the output angular frequency; P i is the output active power; P ref，i is the reference active power; ω N is the rated frequency; is the event-triggered control input.

[0125] It should be noted that the division of various modules in the device / system embodiments is only a logical function division, and all or part of the modules can be integrated into one physical entity or physically separated. The modules can all be implemented in the form of software invoked by a processing element; all be implemented in the form of hardware; or part of the units be implemented in the form of software invoked by a processing element and part of the units be implemented in the form of hardware.

[0126] The implementation principle of the above modules has been described in the foregoing method embodiments, and thus is not repeated here.

[0127] Based on the same concept, in some embodiments of the present application, an electronic device is also provided. The electronic device comprises a memory and a processor, wherein the memory is configured to store a processing program, and the processor is configured to execute the processing program according to an instruction. When the processor executes the processing program, the event-triggered network-forming virtual synchronous machine distributed secondary control method in the foregoing embodiments is implemented.

[0128] In some embodiments of the present application, a readable storage medium is also provided. The readable storage medium can be a non-volatile readable storage medium or a volatile readable storage medium. The readable storage medium stores an instruction, and when the instruction is run on a computer, an electronic device comprising the readable storage medium executes the foregoing event-triggered network-forming virtual synchronous machine distributed secondary control method.

[0129] It can be understood that, for the foregoing event-triggered network-forming virtual synchronous machine distributed secondary control method, if all are implemented in the form of software function modules and sold or used as independent products, the software function modules can be stored in a computer-readable storage medium. Based on this understanding, the technical solutions of the present application or all or part of the technical solutions that essentially contribute to the prior art can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method embodiments of the present application. The foregoing storage medium includes a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various media that can store program codes.

[0130] The computer readable storage medium can include a computer-readable storage medium comprising a computer-readable storage medium that stores the program code. Such a computer-readable storage medium can be a magnetic-disk, a magnetic tape, or any other magnetic medium, an optical medium (e.g., a compact disc (CD), a digital versatile disc (DVD), a Blu-ray disc, a holographic disc, or the like), a solid-state medium (e.g., a RAM, a ROM, an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a flash memory, an optical storage, memory card, or the like), or the like. The computer readable storage medium can also be any volatile or non-volatile storage medium that can store or carry the program code for use by or in connection with an instruction execution system, apparatus, or device.

[0131] The program code can be written in any combination of one or more programming languages, including an object oriented programming language such as Python, C++ or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code can execute entirely on the user's computing device, partly on the user's computing device, as a stand-alone software package, partly on the user's computing device and partly on a remote computing device or entirely on the remote computing device or server. In the latter scenario, the remote computing device can be connected to the user's computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection can be made to an external computing device, such as through the Internet using an Internet Service Provider (ISP).

[0132] Finally, it should be noted that the above-described embodiments are merely intended to illustrate the technical solutions of the present application, and are not intended to limit the present application; even though the above-described embodiments of the present application have been described in detail, those skilled in the art should understand that they can still modify the technical solutions recorded in the above-described embodiments, or make equivalent replacements to some of the technical features; and these modifications or replacements do not cause the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An event-triggered network-forming virtual synchronous machine distributed secondary control method, characterized in that, The application relates to an event-triggered distributed secondary control method for grid-forming virtual synchronous machines (VSGs). The application relates to an event-triggered distributed secondary control method for grid-forming virtual synchronous machines (VSGs). The application relates to an event-triggered distributed secondary control method for grid-forming virtual synchronous machines (VSGs). ， wherein, , is a time-varying gain function, is a preset time-varying function, b and c are gain coefficients, is a user-defined function, is a preset finite time allowed by any physics, the recovery duration is set by setting the value of n, is a constant, satisfying t0 is a preset time at which the secondary control starts to act. The application relates to an event-triggered distributed secondary control method for grid-forming virtual synchronous machines (VSGs).

2. The event-triggered network-forming virtual synchronous machine distributed secondary control method according to claim 1, characterized in that, The application relates to an event-triggered distributed secondary control method for grid-forming virtual synchronous machines (VSGs). ， where J i is the virtual inertia; D i is the damping coefficient; ω i is the output angular frequency; P i is the output active power; P ref，i is the reference active power; ω N is the rated frequency; is the event-triggered control input. The application relates to an event-triggered distributed secondary control method for grid-forming virtual synchronous machines (VSGs). only when is updated and remains constant for intervals, i.e.: ， wherein, is the kth event-triggering time, is the k+1th event-triggering time, is a quadratic control input signal, is an event-triggered control input signal.

4. The event-triggered network-forming virtual synchronous machine distributed secondary control method according to claim 1, characterized in that, The application relates to an event-triggered distributed secondary control method for grid-forming virtual synchronous machines (VSGs). Configuring secondary control input signals , wherein, , is a predetermined time-varying gain function, is an error signal under event-triggered condition, a i、 a j is a parameter for controlling the accurate allocation of active power, ij is an adjacent matrix element, indicating whether i and j have communication or not, g i is the gain coefficient corresponding to the ith DG, used to adjust the influence degree of the control input error e ui on the overall error, N i represents the neighbor set of DG i , j represents the neighbor DG i of DG j .

5. The event-triggered network-forming virtual synchronous machine distributed secondary control method according to claim 1, characterized in that, The application relates to an event-triggered distributed secondary control method for grid-forming virtual synchronous machines (VSGs). Set the first DG in the distributed communication structure as the leader, set u ref The control input variable transmitted for the first DG leader, provide the reference signal of the control input, provide the reference signal for the DGs except the first DG leader, define e ui is: , u i is a secondary control input signal, Defining event-triggered control input with continuous control input u i The error of (t) is: ， triggering instant is determined by the following conditions: ， wherein, is a triggering sensitivity parameter for controlling the triggering frequency; is a design parameter satisfying , is an adjustment parameter, g i is a DG i is a corresponding gain coefficient, N i is a number of neighbor nodes, e is a consistency error satisfying e = u i - u ref t is a real-time time; The following holds true within the trigger interval, which remains constant: 。 6. The event-triggered network-forming virtual synchronous machine distributed secondary control method according to claim 5, characterized in that, The application relates to an event-triggered distributed secondary control method for grid-forming virtual synchronous machines (VSGs). Between two event trigger instants, the DG i an update of the state of the neighbor node is not received, and in case a trigger occurs at an instant ; If no new trigger is performed, the sampling error can be known: ， From t to Integrating gives: , where e i is the proportional error of u i , and the trigger condition is calculated as follows: ； wherein represents an event triggered control input with continuous control input u i error ε of (t) ui derivative with respect to time, represents a quadratic control input signal u i derivative with respect to time.

7. An event-triggered network-forming virtual synchronous machine distributed secondary control system, characterized in that, The application relates to an event-triggered distributed secondary control method for grid-forming virtual synchronous machines (VSGs). The application relates to an event-triggered distributed secondary control method for grid-forming virtual synchronous machines (VSGs). The application relates to an event-triggered distributed secondary control method for grid-forming virtual synchronous machines (VSGs). ， wherein, , is a time-varying gain function, is a preset time-varying function, b and c are gain coefficients, is a user-defined function, is a preset finite time allowed by any physics, the recovery duration is set by setting the value of n, is a constant, satisfying t0is a preset time at which the secondary control starts to act. The application relates to an event-triggered distributed secondary control method for grid-forming virtual synchronous machines (VSGs).

8. The event-triggered networking-based virtual synchronous machine distributed secondary control system according to claim 7, characterized in that, The application relates to an event-triggered distributed secondary control method for grid-forming virtual synchronous machines (VSGs). ， where J i is the virtual inertia; D i is the damping coefficient; ω i is the output angular frequency; P i is the output active power; P ref，i is the reference active power; ω N is the rated frequency; is the event-triggered control input.

9. An electronic device, comprising: The application relates to an event-triggered distributed secondary control method for grid-forming virtual synchronous machines (VSGs). The application relates to an event-triggered distributed secondary control method for grid-forming virtual synchronous machines (VSGs). The application relates to an event-triggered distributed secondary control method for grid-forming virtual synchronous machines (VSGs).

10. A computer-readable storage medium, characterized in that, The application relates to an event-triggered distributed secondary control method for grid-forming virtual synchronous machines (VSGs). The application relates to an event-triggered distributed secondary control method for grid-forming virtual synchronous machines (VSGs). The application relates to an event-triggered distributed secondary control method for grid-forming virtual synchronous machines (VSGs). The application relates to an event-triggered distributed secondary control method for grid-forming virtual synchronous machines (VSGs). The application relates to an event-triggered distributed secondary control method for grid-forming virtual synchronous machines (VSGs). The application relates to an event-triggered distributed secondary control method for grid-forming virtual synchronous machines (VSGs). 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