Classification and coordination control method for optical storage flexible microgrid

Abstract

The application relates to the technical field of direct-current micro-grid, and provides a photovoltaic storage direct-flexible micro-grid classification coordination control method, which comprises the following steps: each distributed photovoltaic device and distributed energy storage device in multiple distributed photovoltaic devices and distributed energy storage devices of a photovoltaic storage direct-flexible micro-grid are connected to a direct-current micro-grid through respective converters; a full-duplex communication network is established between multiple coordination controllers; the coordination controller of a distributed energy storage device node and a distributed photovoltaic device node utilizes the full-duplex communication network to realize observation on the average voltage of a bus corresponding to the distributed energy storage device node through real-time interaction of average voltage estimation values; and the coordination controller of the distributed energy storage device node utilizes a distributed coordination control algorithm of the energy storage node to realize voltage stabilization of the bus where the distributed energy storage device node is located. The technical scheme can realize photovoltaic power generation output current equalization and adjustable output proportion, ensure stable operation of the photovoltaic storage direct-flexible micro-grid, and improve photovoltaic power generation penetration.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of direct-current micro-grid, in particular to a classification and coordination control method of photovoltaic storage and flexible micro-grid. BACKGROUND

[0002] The photovoltaic storage and flexible micro-grid can efficiently integrate photovoltaic power generation and energy storage technology, reduce energy conversion loss through direct-current power distribution, and improve the flexibility of the grid by using flexible regulation technology, so as to realize clean, efficient and stable energy supply, promote the construction of new power system, and help achieve the double carbon goal.

[0003] Photovoltaic power generation devices and energy storage equipment as distributed power sources have significant differences. Photovoltaic power generation devices can realize low-carbon and low-cost power generation, but are susceptible to weather, and have volatility and randomness. Energy storage equipment cannot generate electricity, but can only store and release energy, and has stability and adjustability. The challenge of the photovoltaic storage and flexible micro-grid lies in how to provide sufficient adjustability of the micro-grid system and realize stable operation of the micro-grid system under the condition of high penetration rate of photovoltaic power generation devices and limited energy storage equipment.

[0004] Reasonable voltage deviation is the key to ensuring the safe and stable operation of direct-current loads. The coordination control of distributed energy storage equipment can stabilize the system voltage and effectively control the voltage deviation, but the uncontrollability of photovoltaic power generation poses a challenge to the stable regulation capacity of energy storage equipment. In order to reasonably control the investment cost of energy storage equipment while maintaining a high penetration rate of photovoltaic systems, it is necessary to fully exploit the regulation capacity of photovoltaic systems. Therefore, the common classification and coordination control of photovoltaic power generation devices and energy storage equipment has obvious economic value and practical significance.

[0005] The current direct-current micro-grid distributed coordination control method only considers the coordination control related to energy storage equipment, and treats power sources with volatility and randomness such as photovoltaic power generation devices as loads, without participating in coordination control. This method limits the penetration rate of photovoltaic power generation and requires too high regulation capacity of energy storage equipment. SUMMARY

[0006] The present application provides a classification and coordination control method of photovoltaic storage and flexible micro-grid, which can realize equal division of photovoltaic power generation output current and adjustable output proportion, ensure stable operation of the photovoltaic storage and flexible micro-grid, and improve the penetration rate of photovoltaic power generation.

[0007] The classification and coordination control method of photovoltaic storage and flexible micro-grid of the present application, the photovoltaic storage and flexible micro-grid includes a plurality of distributed photovoltaic devices and distributed energy storage equipment, and the method includes

[0008] Each of the plurality of distributed photovoltaic devices and distributed energy storage devices in the photovoltaic energy storage direct flexible micro-grid is connected to the direct current micro-grid through a respective converter, and each of the converters is configured with a coordination controller;

[0009] A full-duplex communication network is established between the coordination controllers, and the full-duplex communication network includes distributed photovoltaic device nodes and distributed energy storage device nodes;

[0010] The coordination controllers of the distributed photovoltaic device nodes and the distributed energy storage device nodes use the full-duplex communication network to realize observation of the average voltage of the bus corresponding to the distributed energy storage device node through real-time interaction of average voltage estimation values;

[0011] Based on the real-time state information interaction between adjacent nodes in the full-duplex communication network, the coordination controllers of the distributed energy storage device nodes use a distributed coordination control algorithm of the energy storage nodes to realize voltage stabilization of the bus where the distributed energy storage device nodes are located, and the coordination controllers of the distributed photovoltaic device nodes use a distributed coordination control algorithm of the photovoltaic nodes to realize power balance of the direct current micro-grid and adjust the proportion of photovoltaic power supply in the total demand of the load.

[0012] From the above technical solution, compared with the prior art, on the one hand, the classification distributed regulation method adopted in the present application not only fully utilizes the voltage stabilization and power regulation capability of the distributed energy storage device, but also includes photovoltaic device power generation in the regulation range, enhances the flexibility of the system, improves the photovoltaic power consumption capability of the system, and suppresses the excessive demand for the regulation capability of the distributed energy storage device; on the other hand, the classification coordination control method proposed in the present application is realized in a distributed form, only requires a unified full-duplex communication network to be established between the photovoltaic device nodes and the energy storage device nodes, and the data transmitted in the communication network is unified, which is applicable to both photovoltaic devices and energy storage devices, and can realize the classification coordination control target of the photovoltaic devices and the energy storage devices. BRIEF DESCRIPTION OF DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0014] Figure 1 The implementation flowchart of the classification coordination control method of the photovoltaic energy storage direct flexible micro-grid of the present application.

[0015] Figure 2 The system schematic diagram of one embodiment of the present application.

[0016] Figure 3 The schematic diagram of the coordinated control of the energy storage device according to an embodiment of the present application.

[0017] Figure 4 The schematic diagram of the coordinated control of the photovoltaic power generation system according to an embodiment of the present application.

[0018] Figure 5 The schematic diagram of the controlled voltage waveform according to an embodiment of the present application.

[0019] Figure 6 The schematic diagram of the controlled current amplitude waveform according to an embodiment of the present application. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. In the present application, adjectives such as first and second can only be used to distinguish one element or action from another element or action, and do not necessarily require or imply any actual such relationship or sequence. If the environment permits, a reference element or component or step (etc.) should not be interpreted as being limited to only one element, component, or step, but can be one or more elements, components, or steps, etc.

[0021] In the present specification, the sizes of the various parts shown in the drawings are not drawn in accordance with the actual proportional relationship for the convenience of description.

[0022] Photovoltaic (PV) power generation devices and energy storage devices, as distributed power sources, exhibit significant differences. PV power generation devices can achieve low-carbon, low-cost power generation, but are susceptible to climate influences, exhibiting volatility and randomness. Energy storage devices cannot generate electricity; they can only store and release energy, possessing stability and adjustability. The challenge of PV-storage-DC-flexible microgrids lies in integrating high-penetration PV power generation devices while maintaining a limited number of energy storage devices, and in providing sufficient adjustability to ensure stable operation of the microgrid system. Reasonable voltage deviation is crucial for ensuring the safe and stable operation of DC loads. Coordinated control of distributed energy storage devices can stabilize system voltage and effectively control voltage deviations, but the uncontrollability of PV power generation poses a challenge to the stability and regulation capabilities of energy storage devices. To reasonably control the investment cost of energy storage devices while maintaining a high penetration rate of the PV system, it is necessary to fully explore the regulation capabilities of the PV system. Therefore, achieving coordinated control of both PV power generation devices and energy storage devices has significant economic value and practical significance. Current proposed distributed coordinated control methods for DC microgrids often only consider coordinated control related to energy storage devices, treating fluctuating and stochastic power sources such as photovoltaic power generation devices as loads and excluding them from coordinated control. This approach limits the penetration rate of photovoltaic power generation and places excessively high demands on the regulation capabilities of energy storage devices.

[0023] The embodiments of this application will be further described more clearly below with reference to the accompanying drawings. It should be noted that the application of the control method involved in this application is not limited to this embodiment. The control method involved in this application can be applied to different islanded microgrid structures and should be included in the protection scope of this application accordingly.

[0024] like Figure 1 The diagram shown is a flowchart of the implementation of the photovoltaic-storage-DC-flexible microgrid classification and coordination control method involved in this application, including steps S101 to S104, which are described in detail below:

[0025] Step S101: In the photovoltaic-storage-DC-flexible microgrid, each of the multiple distributed photovoltaic devices and distributed energy storage devices is connected to the DC microgrid through its own converter, and each converter is equipped with a coordination controller.

[0026] In this embodiment, the photovoltaic-storage-DC-flexible microgrid includes multiple distributed photovoltaic (PV) devices and distributed energy storage devices. Each PV device and energy storage device is connected to the DC microgrid via its own converter (e.g., a DC / DC converter), and each converter is equipped with a coordination controller. The main function of these coordination controllers is to generate coordination control commands for the corresponding converters, enabling the distributed PV devices and energy storage devices in the PV-storage-DC-flexible microgrid to work collaboratively, thereby achieving bus voltage stability and system power balance in the PV-storage-DC-flexible microgrid.

[0027] Step S102: Establish a full-duplex communication network among the plurality of coordinated controllers, wherein the full-duplex communication network comprises the distributed photovoltaic device nodes and the distributed energy storage device nodes.

[0028] In the embodiments of the present application, the adjacent coordinated controllers in the full-duplex communication network are neighbor nodes, and each node can be any type of node. The information transmitted by each node through the full-duplex communication network is universal and can be received and utilized by any type of node in the full-duplex communication network. It is required to ensure that there is at least one communication path between any two nodes, and each communication path can include multiple nodes. As an embodiment of the present application, the full-duplex communication network among the plurality of coordinated controllers can be established based on the principle of proximity to establish a sparse full-duplex communication network among the plurality of coordinated controllers. As shown in FIG. 1, which is a schematic diagram of a photovoltaic and energy storage direct flexible microgrid according to an embodiment of the present application, Figure 2 Figure 2 The "photovoltaic coordinated control" in FIG. 1 refers to the coordinated controller or its coordinated control function configured for each distributed photovoltaic device, and the "energy storage coordinated control" refers to the coordinated controller or its coordinated control function configured for each distributed energy storage device. The photovoltaic and energy storage direct flexible microgrid can include multiple DC buses and multiple distributed photovoltaic devices and energy storage devices. Each distributed photovoltaic device and distributed energy storage device is configured with a corresponding coordinated controller and is connected to the DC bus through a converter (for example, a DC / DC converter). A full-duplex communication network is established among the coordinated controllers. The total number of power supply nodes in the photovoltaic and energy storage direct flexible microgrid is N=7, the number of energy storage nodes is m=3, the labels are {2, 4, 7}, the number of photovoltaic nodes is N-m=4, the labels are {1, 3, 5, 6}, and the information transmitted by any node i (distributed photovoltaic device or distributed energy storage device) in the communication network is the output current reference value of the corresponding converter and the average voltage estimation value of the energy storage node bus The present application does not have special requirements for the topology of the electrical and communication network, the configuration and location selection of the distributed photovoltaic and energy storage nodes, and is applicable to the classification coordinated control method described in the present application.

[0029] In the embodiments of the present application, Figure 2 In the example of the photovoltaic and energy storage direct flexible microgrid, the communication between any two nodes can adopt wired or wireless communication mode, and the entire communication network can be sparse, but it is required to have connectivity, that is, there is a communication path from any node to any other node.

[0030] ​The so-called principle of proximity refers to preferentially establishing a communication connection between distributed power sources and their coordination controllers that are relatively close in geographical position to reduce communication delay and improve the overall response speed of the system. The "sparsity" of the full-duplex communication network refers to not establishing a full connection network between all coordination controllers of the optical storage direct flexible micro-grid, but only establishing a direct communication connection between some adjacent nodes. The sparse communication network can effectively reduce the complexity and communication load of the network while ensuring basic network connectivity. Specifically, based on the principle of proximity, the establishment of a sparse full-duplex communication network between multiple coordination controllers can be: by initially calculating or measuring the physical distance or electrical topological distance between distributed power source nodes, selecting some nodes closest in distance to establish a communication connection; among all possible node pairs, only selecting a communication connection between some nodes; in the above scheme, the selection of node connection follows the following conditions: 1) node pairs that meet the principle of proximity; 2) ensuring the connectivity of the network within the entire network range, i.e., each node can communicate with any other node through several hops (through the forwarding of other nodes), and the distance evaluation can be based on actual geographical coordinates, network topology, or electrical distance (such as resistance, inductance, etc.).

[0031] In an embodiment of the present application, based on the principle of proximity, the establishment of a sparse full-duplex communication network between multiple coordination controllers can be: based on the principle of proximity, the establishment of a sparse self-organizing full-duplex communication network between multiple coordination controllers. Compared with ordinary full-duplex communication networks, self-organizing full-duplex communication networks have strong robustness and fault recovery capability, and the establishment of a sparse self-organizing full-duplex communication network can be achieved through the following steps S1021 to S1024:

[0032] Step S1021: Based on the initial detection result, select several nodes closest in distance for initial connection.

[0033] Each coordination controller enters an initial state when starting, scans the surrounding environment, detects adjacent other coordination controllers, and based on the initial detection result, selects several nodes closest in distance for initial connection to form a basic self-organizing network structure.

[0034] Step S1022: Dynamically adjust the network topology of the full-duplex communication network formed.

[0035] With the operation of the full-duplex communication network, each coordination controller continuously measures and evaluates the connection quality with adjacent nodes, including signal strength, delay, bandwidth, etc. If it is detected that the connection quality drops below a threshold value, the controller will automatically search for a new alternative connection and readjust its communication path to maintain the robustness of the network. The adjustment of the topology of the full-duplex communication network can be automatically performed through a self-organizing protocol without human intervention.

[0036] Step S1023: Maintain redundant paths for the full-duplex communication network.

[0037] In this embodiment, the coordination controller within the ad hoc network maintains a set of redundant communication paths based on the path discovery mechanism in the ad hoc protocol. During normal operation, both the primary and backup paths are monitored simultaneously. If the primary path fails, the system automatically switches to the backup path to ensure communication continuity. It should be noted that the path discovery mechanism in the ad hoc protocol can be updated periodically during network operation.

[0038] Step S1024: When a network failure occurs, the redundant path maintained by the full-duplex communication network is activated to recover from the failure.

[0039] On the one hand, when a node fails or loses connection, the surrounding coordination controllers will detect the disappearance of the node and activate the path discovery mechanism to automatically start the path reassembly process. On the other hand, the failure event can be notified to other nodes through broadcast or multicast, and the nodes can quickly adjust their connection strategies to re-establish connections with the remaining nodes in order to restore the overall network connectivity.

[0040] In another embodiment of this application, the sparse full-duplex communication network supports the dynamic addition and removal of nodes and automatically updates the communication path when nodes change.

[0041] Step S103: The coordination controllers of the distributed energy storage device nodes and the distributed photovoltaic device nodes use a full-duplex communication network to observe the average voltage of the bus corresponding to the distributed energy storage device nodes through real-time interactive average voltage estimates.

[0042] like Figure 3 The diagram shown is a schematic of an embodiment to which this application applies, in which each energy storage device node is configured with a corresponding coordination controller. Each coordination controller includes an average voltage observer and a bus voltage controller. Figure 3 The "distributed coordination controller for energy storage nodes" refers to the coordination controller configured for each converter of the distributed energy storage device.

[0043] In one embodiment of this application, the coordination controller of the distributed energy storage device node and the distributed photovoltaic device node utilizes a full-duplex communication network to observe the average voltage of the DC bus corresponding to the distributed energy storage device node through real-time interactive average voltage estimation. This can be achieved by the average voltage observer of the distributed energy storage device node observing the average voltage of the DC bus corresponding to the distributed energy storage device node based on the following average voltage observation algorithm:

[0044]

[0045] wherein m represents the number of distributed energy storage device nodes in the optical storage direct-flexible micro-grid, N-m represents the number of distributed photovoltaic device nodes, represents the observation value of the i-th distributed energy storage device node to the average voltage of the bus corresponding to all distributed energy storage device nodes, represents the observation value of the i-th distributed energy storage device node to the average voltage of the bus corresponding to all distributed energy storage device nodes received by node j in the full-duplex communication network, V i represents the measurement value of the bus voltage corresponding to the i-th distributed energy storage device node, and respectively represent and the first-order differential operation of V i , a ij represents the communication link weight between node i and node j, a ij > 0, otherwise a ij = 0. It should be noted that the average voltage observer output of the above distributed energy storage device node will be used as the input reference signal of the bus voltage controller.

[0046] As shown in Figure 4 , in one embodiment of the application, any distributed photovoltaic device node is configured with a corresponding coordination controller, and the coordination controller includes an average voltage observer and a bus voltage controller, Figure 4 The "energy storage node distributed coordination controller" in the above formula is the coordination controller configured for the converter of each distributed energy storage device. In another embodiment of the application, the coordination controllers of the distributed energy storage device nodes and the distributed photovoltaic device nodes utilize the full-duplex communication network to realize the observation of the average voltage of the direct-current bus corresponding to the distributed energy storage device node through real-time interaction of the average voltage estimation value, which can be that the average voltage observer of the distributed photovoltaic device node observes the average voltage of the direct-current bus corresponding to the distributed energy storage device node based on the following average voltage observation algorithm:

[0047]

[0048] wherein, represents the observation value of the k-th distributed photovoltaic device node to the average voltage of the bus corresponding to all energy storage device nodes in the optical storage direct-flexible micro-grid, a kj represents the communication link weight between node k and node j.

[0049] Step S104: Based on the interaction of real-time state information between adjacent nodes of the full-duplex communication network, the coordination controller of the distributed energy storage device node uses the distributed coordination control algorithm of the energy storage node to realize the voltage stability of the bus where the distributed energy storage device node is located, and the coordination controller of the distributed photovoltaic device node uses the distributed coordination control algorithm of the photovoltaic node to realize the power balance of the DC microgrid and adjust the proportion of photovoltaic power supply in the total demand of the load.

[0050] As shown in Figure 3 , it is a schematic diagram of any energy storage device node in an embodiment to which the application is applicable, and each coordination controller includes an average voltage observer and a bus voltage controller. The coordination controllers corresponding to the distributed energy storage device nodes and the distributed photovoltaic device nodes use the full-duplex communication network to realize the observation of the average voltage of the DC bus corresponding to the distributed energy storage device node through the real-time interaction of the average voltage estimation value. The average voltage observer of the distributed energy storage device node can observe the average voltage of the DC bus corresponding to the distributed energy storage device node based on the following average voltage observation algorithm:

[0051]

[0052] As an embodiment of the application, based on the interaction of real-time state information between adjacent nodes of the full-duplex communication network, the coordination controller of the distributed energy storage device node uses the distributed coordination control algorithm of the energy storage node to realize the voltage stability of the bus where the distributed energy storage device node is located. For the distributed energy storage device node, the following bus voltage control law is adopted, and the bus voltage deviation is adjusted through the voltage deviation parameter to realize the average voltage stability of the corresponding bus at the rated value:

[0053]

[0054]

[0055]

[0056]

[0057]

[0058] wherein u i is the control signal of the coordination controller of the i-th distributed energy storage device node output to the corresponding converter, V rat represents the rated value of the DC microgrid bus voltage, r i > 0 is the droop coefficient, I i is the current output by the i-th distributed energy storage device node, and respectively represent the droop control current and voltage correction amount of the i-th distributed energy storage device node, state information received by the i-th distributed energy storage device node from neighbor nodes, the neighbor nodes including distributed energy storage device nodes or distributed photovoltaic device nodes, representing the output current unit value of the i-th distributed energy storage device node, representing the bus voltage zero reference value of the i-th distributed energy storage device node, 1 m representing a unit vector with dimension m, representing the maximum output current of the distributed photovoltaic device node, θ ∈ [0, 1] is the voltage deviation coefficient in the coordination controller of the distributed energy storage device node, when θ = 0, all bus voltage deviations are 0, reaching the minimum value, when θ increases from 0, all bus voltage deviations increase accordingly, when θ = 1, all bus voltage deviations are at their maximum values, ω > 0 is the output proportion coefficient, the smaller ω is, the greater the photovoltaic output is, the less the light is abandoned, the greater ω is, the smaller the photovoltaic output is, the more the light is abandoned, representing the admittance matrix of the photovoltaic energy storage direct flexible microgrid, is a real diagonal matrix, the diagonal elements representing the equivalent admittance of the load, Y+Y L representing a block matrix, is:

[0059]

[0060]

[0061]

[0062] As shown in Figure 4 , in any one of the embodiments to which the present application is applicable, each distributed photovoltaic device node is configured with a corresponding coordination controller, and the coordination controller includes an average voltage observer and a bus voltage controller. The coordination controllers corresponding to the distributed energy storage device nodes and the distributed photovoltaic device nodes utilize a full-duplex communication network to realize observation of the average voltage of the direct-current bus corresponding to the distributed energy storage device node through real-time interaction of average voltage estimation values, which can be: the average voltage observer of the distributed photovoltaic device node observes the average voltage of the direct-current bus corresponding to the distributed energy storage device node based on the following average voltage observation algorithm:

[0063]

[0064] As another embodiment of the present application, the coordination controller of the distributed photovoltaic device node utilizes a photovoltaic node distributed coordination control algorithm to realize power balance of the direct current microgrid and adjust the proportion of photovoltaic power supply in the total demand of the load, including: for the distributed photovoltaic device node, the following bus voltage control law is adopted to realize that the ratio of the output current of each distributed photovoltaic device node to the rated output current of each distributed photovoltaic device node is equal:

[0065]

[0066]

[0067]

[0068] wherein u k is the control signal output by the coordination controller of the kth distributed photovoltaic device node to the corresponding converter, is the state information received by the kth distributed photovoltaic device node from the neighbor nodes, the neighbor nodes can be the distributed energy storage device nodes or the distributed photovoltaic device nodes, represents the unit value of the output current of the kth distributed photovoltaic device node, and the represents the droop control current correction amount of the kth distributed photovoltaic device node, I k is the current output by the kth distributed photovoltaic device node, is the maximum output current of the kth distributed photovoltaic device node.

[0069] The method of the above embodiment of the present application can further include: adjusting the voltage deviation coefficient in the coordination controller of the distributed energy storage device node according to the maximum voltage deviation allowed by the direct current bus in the photovoltaic energy storage direct flexible microgrid, so that the bus voltage deviation of the distributed energy storage device node in the photovoltaic energy storage direct flexible microgrid meets the voltage quality requirement, wherein the value range of the voltage deviation coefficient θ in the coordination controller is θ∈[0, θ d ], and θ d can be solved according to the following formula:

[0070]

[0071] wherein ΓV is the maximum voltage deviation allowed by the direct current bus in the photovoltaic energy storage direct flexible microgrid, Ψ=[ψ1, ψ2, …, ψ N ] T is an intermediate variable and has no actual physical meaning, and represents the rated maximum output current of the distributed energy storage device node.

[0072] For a given voltage deviation coefficient θ, the adjustable range of the output proportion coefficient ω is determined by the following calculation formula:

[0073]

[0074] in, ζ i and v i This is an intermediate variable in the calculation process. The output ratio coefficient ω mentioned above is used to adjust the output ratio of distributed photovoltaic equipment nodes and distributed energy storage equipment nodes to the load; within the adjustable range of ω, the output current of distributed photovoltaic equipment nodes decreases monotonically as ω increases, and the total output current of all distributed energy storage equipment nodes increases monotonically as ω increases.

[0075] like Figure 5 The figure shows the bus voltage simulation waveform of a simulation example under normal operating conditions according to an embodiment of this application. The system rated voltage V rat =380V, the permissible range of the distributed energy storage device node bus voltage is [372.4, 387.6], such as Figure 6 The figure shows the simulated waveforms of the per-unit output current at each node. This simulation example is divided into four stages:

[0076] In stage 1, t∈[0,5)s, the parameters θ=1 and ω=2 are set in the coordination controller of the distributed energy storage device node. In this stage, the bus voltage V2 of distributed energy storage device node 2 exceeds the allowable range. The per-unit values ​​of the output current of all distributed energy storage device nodes and distributed photovoltaic device nodes are consistent, that is, the output of each power source is equal.

[0077] In stage 2, t∈[5,10)s, the parameters θ=0.63 and ω=2 are set in the coordination controller of the distributed energy storage device node. In this stage, the bus voltage of all distributed energy storage device nodes is within the allowable range, the per-unit value of the output current of all distributed photovoltaic device nodes remains consistent, and the per-unit value of the output current of distributed photovoltaic device nodes is no longer consistent.

[0078] In stage 3, t∈[10,15)s, the parameters θ=0 and ω=2 are set in the coordination controller of the distributed energy storage device node. In this stage, the bus voltage of all distributed energy storage device nodes reaches the rated voltage of 380V. The per-unit value of the output current of all distributed photovoltaic device nodes remains consistent, but the degree of inconsistency of the per-unit value of the output current of distributed photovoltaic device nodes increases.

[0079] In stage 4, t∈[10,15)s, the parameters θ=0 and ω=1.71 are set in the distributed energy storage device node coordination controller. In this stage, the bus voltage of all distributed energy storage device nodes remains at the rated voltage of 380V. The per-unit value of the output current of the distributed photovoltaic device nodes increases, and the output power increases. The per-unit value of the output current of each distributed energy storage device node decreases, and the output power decreases.

[0080] The effective control of the distributed energy storage device node bus voltage is achieved by adjusting θ, and the control of the size of the distributed photovoltaic device node output is achieved by adjusting ω.

[0081] From Figure 1 It can be known from the example photovoltaic storage direct flexible microgrid classification coordination control method that, on the one hand, the classification distributed regulation method adopted by the present application not only fully utilizes the voltage stability and power regulation capability of the distributed energy storage device, but also includes the photovoltaic device power generation into the regulation range, enhances the flexibility of the system, improves the system's ability to absorb photovoltaic power generation, and suppresses the excessive demand for the regulation capability of the distributed energy storage device; on the other hand, the classification coordination control method proposed by the present application is realized in a distributed form, only requiring a unified full-duplex communication network to be established between the photovoltaic device node and the energy storage device node, and the data transmitted in the communication network is unified, which is applicable to both photovoltaic devices and energy storage devices, and can realize the classification coordination control target of the photovoltaic device and the energy storage device

[0082] The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements to some technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application. The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present application, and it should be understood that the above description is only the specific embodiment of the present application, and is not used to limit the protection scope of the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A light storage direct flexible micro-grid classification coordination control method, characterized in that, The light-storage direct-flexible micro-grid comprises a plurality of distributed photovoltaic devices and distributed energy storage devices, and the method comprises: Each of the plurality of distributed photovoltaic devices and distributed energy storage devices of the light-storage direct-flexible micro-grid is connected to a direct-current micro-grid through a respective converter, and each of the converters is provided with a coordinated controller, and the coordinated controller comprises a bus voltage controller; A full-duplex communication network is established between the plurality of coordinated controllers, and the full-duplex communication network comprises distributed photovoltaic device nodes and distributed energy storage device nodes; The coordinated controllers of the distributed photovoltaic device nodes and the distributed energy storage device nodes utilize the full-duplex communication network to realize observation of average voltage of a bus corresponding to the distributed energy storage device nodes through real-time interaction of average voltage estimation values; Based on real-time state information interaction between adjacent nodes in the full-duplex communication network, the coordinated controllers of the distributed energy storage device nodes utilize a distributed energy storage node coordinated control algorithm to realize voltage stabilization of a bus where the distributed energy storage device nodes are located, and the coordinated controllers of the distributed photovoltaic device nodes utilize a photovoltaic node distributed coordinated control algorithm to realize power balance of the direct-current micro-grid and adjust a proportion of photovoltaic power supply in total load demand; Based on real-time state information interaction between adjacent nodes in the full-duplex communication network, the coordinated controllers of the distributed energy storage device nodes utilize a distributed energy storage node coordinated control algorithm to realize voltage stabilization of a bus where the distributed energy storage device nodes are located, and the coordinated controllers of the distributed photovoltaic device nodes utilize a photovoltaic node distributed coordinated control algorithm to realize power balance of the direct-current micro-grid and adjust a proportion of photovoltaic power supply in total load demand; The m represents the number of distributed energy storage device nodes in the optical storage direct flexible micro-grid, and the u i is the control signal of the coordinating controller of the i th distributed energy storage device node output to the corresponding converter, the V rat represents the rated value of the DC micro-grid bus voltage, the r i >0 is the droop coefficient, the I i is the current output by the i th distributed energy storage device node, and the and respectively represent the droop control current and the voltage correction amount of the i th distributed energy storage device node, is the state information received by the i th distributed energy storage device node from the neighbor nodes, the neighbor nodes including the distributed energy storage device nodes or the distributed photovoltaic device nodes, and the represents the output current unit value of the i th distributed energy storage device node, and the represents the bus voltage zero reference value of the i th distributed energy storage device node, and the 1 m represents a unit vector with a dimension of m, and the represents the maximum output current of the distributed photovoltaic device node, the θ ∈ [0, 1] is the voltage deviation coefficient in the coordinating controller of the distributed energy storage device node, the ω > 0 is the output proportion coefficient, and the represents the admittance matrix of the optical storage direct flexible micro-grid, and the is a real diagonal matrix, and the diagonal elements represent the equivalent admittance of the load, Y+Y L represents a block matrix, which is: 2.The method of claim 1, wherein, The coordinated controllers of the distributed photovoltaic device nodes comprise average voltage observers; The coordinated controllers of the distributed photovoltaic device nodes and the distributed energy storage device nodes utilize the full-duplex communication network to realize observation of average voltage of a bus corresponding to the distributed energy storage device nodes through real-time interaction of average voltage estimation values, and the average voltage observers of the distributed photovoltaic device nodes observe average voltage of a bus corresponding to the distributed energy storage device nodes based on the following average voltage observation algorithm: wherein the represents the observation value of the i-th distributed energy storage device node to the average voltage of the bus corresponding to all distributed energy storage device nodes, and the represents the observation value of the i-th distributed energy storage device node to the average voltage of the bus corresponding to all distributed energy storage device nodes received by the node j in the full-duplex communication network, V i represents the measurement value of the bus voltage corresponding to the i-th distributed energy storage device node, and respectively represent and the first-order differential operation of V i a ij represents the communication link weight between the node i and the node j. 3.The method of claim 1, wherein, The coordinated controllers of the distributed photovoltaic device nodes comprise average voltage observers; The coordinated controllers of the distributed photovoltaic device nodes and the distributed energy storage device nodes utilize the full-duplex communication network to realize observation of average voltage of a bus corresponding to the distributed energy storage device nodes through real-time interaction of average voltage estimation values, and the average voltage observers of the distributed photovoltaic device nodes observe average voltage of a bus corresponding to the distributed energy storage device nodes based on the following average voltage observation algorithm: wherein, Vk, k represents the observation of the bus average voltage of all energy storage device nodes in the kth distributed photovoltaic device node, and the Vj, k represents the observation of the bus average voltage of all energy storage device nodes received by the ith distributed energy storage device node in the full-duplex communication network, a kj Vk, j represents the communication link weight between node k and node j. 4.The method of claim 3, wherein, The coordinated controllers of the distributed photovoltaic device nodes comprise bus voltage controllers; The coordination controller of the distributed photovoltaic device node utilizes a photovoltaic node distributed coordination control algorithm to realize power balance of the direct-current microgrid and adjust the proportion of photovoltaic power supply in total load demand, including: for the distributed photovoltaic device node, the following bus voltage control law is adopted to realize that the ratio of output current of each distributed photovoltaic device node to the rated output current is equal: wherein the u k is the control signal of the coordinating controller of the kth distributed photovoltaic device node output to the corresponding converter, the is the state information received by the kth distributed photovoltaic device node from the neighbor node, which can be a distributed energy storage device node or a distributed photovoltaic device node, represents the output current unit value of the kth distributed photovoltaic device node, the represents the droop control current correction amount of the kth distributed photovoltaic device node, the I k is the current output by the kth distributed photovoltaic device node, the is the maximum current output by the kth distributed photovoltaic device node. 5.The method of claim 1, wherein, The method further includes: according to the maximum voltage deviation allowed by the direct-current bus in the photovoltaic storage direct-flexible microgrid, adjusting the voltage deviation coefficient in the coordination controller of the distributed energy storage device node, so that the bus voltage deviation of the distributed energy storage device node in the photovoltaic storage direct-flexible microgrid meets the voltage quality requirement. 6.The method of claim 5, wherein, The voltage deviation coefficient θ is in the range of θ∈[0, θ d ], and θ d is solved according to the following formula: Wherein, the Γ V is the maximum voltage deviation allowed for the DC bus in the optical storage direct flexible micro-grid, the Ψ = [ψ1, ψ2, …, ψ N ] T is an intermediate variable, the represents the rated maximum output current of the distributed energy storage device node.

7. The method of claim 5, wherein the method further comprises: For a given voltage deviation coefficient θ, the adjustable range of the output proportion coefficient ω is determined by the following calculation formula: wherein the ζ i and v i are intermediate variables in the calculation process, 8.The method of claim 1 to 7, wherein, The full-duplex communication network is established between the multiple coordination controllers, including: Based on the principle of proximity, a sparse full-duplex communication network is established between the multiple coordination controllers. 9.The method of claim 8, wherein, The sparse full-duplex communication network is established between the multiple coordination controllers based on the principle of proximity, including: based on the principle of proximity, a sparse self-organizing full-duplex communication network is established between the multiple coordination controllers.

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