Classification coordination control method for optical storage direct-flexible micro-grid

Abstract

The invention relates to the technical field of direct-current micro-grids, and provides an optical storage direct-current flexible micro-grid classification coordination control method, which comprises the following steps that: each distributed photovoltaic device and each distributed energy storage device in a plurality of distributed photovoltaic devices and distributed energy storage devices of an optical storage direct-current flexible micro-grid are respectively connected to a direct-current micro-grid through respective current converters; establishing a full duplex communication network among the plurality of coordination controllers; the coordination controller of the distributed energy storage equipment nodes and the distributed photovoltaic equipment nodes utilizes a full-duplex communication network to realize observation of bus average voltage corresponding to the distributed energy storage equipment nodes through real-time interaction of average voltage estimated values; and the coordination controller of the distributed energy storage equipment node realizes voltage stabilization of a bus where the distributed energy storage equipment node is located by using an energy storage node distributed coordination control algorithm. According to the technical scheme, the photovoltaic power generation output current can be equally divided, the output ratio can be adjusted, the stable operation of the photovoltaic storage direct-flexible micro-grid is ensured, and the photovoltaic power generation permeability is improved.

Description

Technical Field

[0001] The present application relates to the technical field of direct current microgrids, and in particular to a classification and coordination control method for a photovoltaic-storage direct current flexible microgrid. Background Art

[0002] The flexible direct-current microgrid with photovoltaic energy storage can efficiently integrate photovoltaic power generation and energy storage technology, reduce energy conversion losses through direct current distribution, and improve grid flexibility using flexible regulation technology, thereby achieving clean, efficient and stable energy supply, promoting the construction of new power systems, and helping to achieve the dual carbon goals.

[0003] Photovoltaic power generation devices and energy storage devices are distributed power sources with significant differences. Photovoltaic power generation devices can achieve low-carbon, low-cost power generation, but are easily affected by climate and have volatility and randomness. Energy storage devices cannot produce electricity, but can only store and release energy, and have stability and adjustability. The challenge of the photovoltaic storage direct flexible microgrid lies in the integration of high-penetration photovoltaic power generation devices, and how to provide sufficient adjustability of the microgrid system to achieve stable operation of the microgrid system when the energy storage equipment is limited.

[0004] Reasonable voltage deviation is the key to ensure the safe and stable operation of DC loads. Coordinated control of distributed energy storage devices can stabilize system voltage and effectively control voltage deviation, but the uncontrollability of photovoltaic power generation poses a challenge to the stable regulation ability of energy storage devices. In order to maintain a high penetration rate of photovoltaic systems while reasonably controlling the investment cost of energy storage equipment, it is necessary to fully explore the regulation ability of photovoltaic systems. Therefore, it is of obvious economic value and practical significance to realize the common classification and coordinated control of photovoltaic power generation devices and energy storage devices.

[0005] The distributed coordinated control methods for DC microgrids that have been proposed often only consider coordinated control related to energy storage devices, and treat volatile and random power sources such as photovoltaic power generation devices as loads, which do not participate in coordinated control. This method limits the penetration rate of photovoltaic power generation and places too high requirements on the regulation capacity of energy storage devices. Summary of the invention

[0006] The present application provides a classification and coordinated control method for a photovoltaic, storage, direct and flexible microgrid, which can achieve equal distribution of photovoltaic power generation output current and adjustable output ratio, ensure stable operation of the photovoltaic, storage, direct and flexible microgrid, and improve the penetration rate of photovoltaic power generation.

[0007] The photovoltaic storage direct flexible microgrid classification coordination control method of the present application, the photovoltaic storage direct flexible microgrid includes a plurality of distributed photovoltaic devices and distributed energy storage devices, and the method includes

[0008] Each of the multiple distributed photovoltaic devices and distributed energy storage devices in the photovoltaic-storage direct-current microgrid is connected to the DC microgrid through its own converter, and each of the converters is configured with a coordination controller;

[0009] Establishing a full-duplex communication network between the plurality of coordination controllers, wherein the full-duplex communication network includes distributed photovoltaic device nodes and distributed energy storage device nodes;

[0010] The coordination controller of the distributed energy storage device node and the distributed photovoltaic device node utilizes the full-duplex communication network to observe the average bus voltage corresponding to the distributed energy storage device node through real-time interactive average voltage estimation value;

[0011] Based on the interaction of real-time status information between adjacent nodes in the full-duplex communication network, the coordination controller of the distributed energy storage device node utilizes the distributed coordination control algorithm of the energy storage node to achieve voltage stability of the bus where the distributed energy storage device node is located. The coordination controller of the distributed photovoltaic device node utilizes the distributed coordination control algorithm of the photovoltaic node to achieve power balance of the DC microgrid and adjust the proportion of photovoltaic power supply in the total load demand.

[0012] It can be seen from the above technical scheme that compared with the prior art, the present application, on the one hand, adopts a classified distributed regulation method that not only fully utilizes the voltage stability and power regulation capabilities of distributed energy storage equipment, but also incorporates photovoltaic equipment power generation into the regulation range, thereby enhancing the elasticity of the system, improving the system's ability to absorb photovoltaic power generation, and alleviating the excessive demand for the regulation capabilities of distributed energy storage equipment; on the other hand, the classified coordinated control method proposed in the present application is implemented in a distributed form, and only requires the establishment of a unified full-duplex communication network between photovoltaic device nodes and energy storage device nodes. The data transmitted in the communication network is unified, which is applicable to both photovoltaic devices and energy storage devices, and can achieve the classified coordinated control goals of photovoltaic devices and energy storage devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0014] Figure 1 This is an implementation flow chart of the classified coordinated control method of the photovoltaic storage direct-flexible microgrid of this application.

[0015] Figure 2 A system diagram of an embodiment of the present application.

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

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

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

[0019] Figure 6 A schematic diagram of a per-unit value waveform of a controlled current according to an embodiment of the present application. DETAILED DESCRIPTION

[0020] The technical scheme in the embodiment of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiment of the present application. In the present application specification, adjectives such as first and second can only be used to distinguish an element or action from another element or action, without requiring or implying any actual such relationship or order. Where circumstances permit, reference to elements or parts or steps (etc.) should not be interpreted as being limited to only one of elements, parts, or steps, but can be one or more of elements, parts, or steps, etc.

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

[0022] Photovoltaic power generation devices and energy storage devices, as distributed power sources, have significant differences. Photovoltaic power generation devices can achieve low-carbon, low-cost power generation, but are easily affected by climate and have volatility and randomness. Energy storage devices cannot produce electricity, but can only store and release energy, and have stability and adjustability. The challenge of the photovoltaic storage direct flexible microgrid lies in the integration of high-penetration photovoltaic power generation devices, and how to provide sufficient adjustability of the microgrid system to achieve stable operation of the microgrid system when the energy storage equipment is limited. Reasonable voltage deviation is the key to ensuring the safe and stable operation of DC loads. Coordinated control of distributed energy storage devices can stabilize the system voltage and effectively control the voltage deviation, but the uncontrollability of photovoltaic power generation poses a challenge to the stable adjustment ability of energy storage devices. 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 explore the adjustment ability of photovoltaic systems. Therefore, it is of obvious economic value and practical significance to realize the common classification and coordinated control of photovoltaic power generation devices and energy storage devices. The distributed coordinated control methods for DC microgrids that have been proposed often only consider coordinated control related to energy storage devices, and treat volatile and random power sources such as photovoltaic power generation devices as loads, which do not participate in coordinated control. This method limits the penetration rate of photovoltaic power generation and places too high requirements on the regulation capacity of energy storage devices.

[0023] The following is a further and clearer description of the embodiments of the present application in conjunction with the accompanying drawings. It should be noted that the control method involved in the present application is not limited to the present embodiment, and the control method involved in the present application is applicable to different island microgrid structures, and the corresponding ones should also be included in the protection scope of the present application.

[0024] like Figure 1 As shown, it is a flowchart of the implementation of the classification coordination control method of the photovoltaic storage direct flexible microgrid involved in this application, including steps S101 to S104, which are described in detail as follows:

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

[0026] In an embodiment of the present application, the photovoltaic storage direct flexible microgrid includes multiple distributed photovoltaic devices and distributed energy storage devices. Each distributed photovoltaic device and energy storage device is connected to the DC microgrid through their own converters (for example, DC / DC converters), and each converter is configured with a coordination controller. The main function of these coordination controllers is to generate coordination control instructions for the corresponding converters, so that each distributed photovoltaic device and energy storage device in the photovoltaic storage direct flexible microgrid can work together to achieve bus voltage stability and system power balance in the photovoltaic storage direct flexible microgrid.

[0027] Step S102: establishing a full-duplex communication network among multiple coordination controllers, wherein the full-duplex communication network includes distributed photovoltaic device nodes and distributed energy storage device nodes.

[0028] In an embodiment of the present application, adjacent coordination controllers in a full-duplex communication network are neighbor nodes. The neighbor nodes of 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 necessary to ensure that there is at least one communication path between any two nodes, and each communication path can contain multiple nodes. As an embodiment of the present application, establishing a full-duplex communication network between multiple coordination controllers can be: based on the principle of proximity, a sparse full-duplex communication network is established between multiple coordination controllers. Figure 2 , which is a schematic diagram of a photovoltaic-storage-direct-flexible microgrid according to an embodiment of the present application. Figure 2 The "photovoltaic coordinated control" in the text refers to the coordinated controller or its coordinated control function configured for the converter of each distributed photovoltaic device, and the "energy storage coordinated control" refers to the coordinated controller or its coordinated control function configured for the converter of each distributed energy storage device. The photovoltaic-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 connected to the DC bus through a converter (for example, a DC / DC converter). A full-duplex communication network is established between the coordinated controllers. The total number of power supply nodes in the photovoltaic-storage-direct-flexible microgrid is N=7, the number of energy storage nodes is m=3, numbered {2, 4, 7}, and the number of photovoltaic nodes is Nm=4, numbered {1, 3, 5, 6}. The information transmitted by any node i (distributed photovoltaic device or distributed energy storage device) in the communication network is the corresponding converter output current per unit value and the estimated value of the average bus voltage of the energy storage node. This application has no special requirements for the topological structure of the electrical and communication networks, the configuration and location selection of distributed photovoltaic and energy storage nodes, all of which are applicable to the classified coordinated control method described in this application.

[0029] exist Figure 2 In the example photovoltaic-storage direct-flexible microgrid, communication between any two nodes can be done by wired or wireless communication. 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 proximity principle refers to the priority of establishing communication connections between distributed power sources and their coordination controllers that are relatively close in geographical location, so as to reduce communication delays and improve the overall response speed of the system. The "sparseness" of the full-duplex communication network means that a fully connected network is not established between the coordination controllers of the entire photovoltaic storage direct flexible microgrid, but only direct communication connections are established 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 proximity principle, a sparse full-duplex communication network can be established between multiple coordination controllers: by preliminarily calculating or measuring the physical distance or electrical topological distance between distributed power nodes, a communication connection is selected between some of the closest nodes; among all possible node pairs, only some nodes are selected to establish communication connections; in the above scheme, the selection of node connections follows the following conditions, namely: 1) node pairs that meet the proximity principle; 2) the ability to ensure network connectivity within the entire network, that is, each node can communicate with any other node through several jumps (through forwarding by other nodes), and the distance evaluation can be based on actual geographic coordinates, network topology or electrical distance (such as resistance, induction, etc.).

[0031] In one embodiment of the present application, based on the principle of proximity, a sparse full-duplex communication network is established between multiple coordination controllers. Based on the principle of proximity, a sparse self-organizing full-duplex communication network is established between multiple coordination controllers. Compared with an ordinary full-duplex communication network, a self-organizing full-duplex communication network has stronger 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 that are closest to each other for initial connection.

[0033] Each coordination controller enters the initial state at startup, scans the surrounding environment, detects other nearby coordination controllers, and based on the initial detection results, selects several nearest nodes for initial connection to form a basic self-organizing network structure.

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

[0035] As the full-duplex communication network operates, each coordination controller continuously measures and evaluates the quality of the connection with neighboring nodes, including parameters such as signal strength, delay, and bandwidth. If it detects that the quality of a connection has dropped below a threshold, the controller will automatically search for a new alternative connection and readjust its communication path to maintain the robustness of the network. The topology of the full-duplex communication network can be adjusted automatically through a self-organizing protocol without manual intervention.

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

[0037] In an embodiment of the present application, the coordination controller in the self-organizing network maintains a set of redundant communication paths based on the path discovery mechanism in the self-organizing protocol. During normal operation, the main path and the backup path are monitored simultaneously. Once the main path fails, it automatically switches to the backup path to ensure the continuity of communication. It should be noted that during the operation of the network, the path discovery mechanism in the self-organizing protocol can be regularly updated.

[0038] Step S1024: When a network failure occurs, the redundant path maintained by the full-duplex communication network is enabled 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 enable the path discovery mechanism to automatically start the path reorganization process; on the other hand, it can notify other nodes of the failure event through broadcast or multicast, and quickly adjust its own connection strategy to re-establish connection with the remaining nodes to restore the connectivity of the overall network.

[0040] In another embodiment of the present application, the sparse full-duplex communication network supports dynamic joining and exiting of nodes, and automatically updates the communication path when the node changes.

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

[0042] like Figure 3 , which is a schematic diagram of an embodiment applicable to the present application, in which any 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 of energy storage nodes” is the coordination controller configured for the converters of the distributed energy storage devices.

[0043] In one embodiment of the present application, the coordination controller of the distributed energy storage device node and the distributed photovoltaic device node uses 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. The average voltage observer of the distributed energy storage device node observes 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] Among them, m represents the number of distributed energy storage device nodes in the photovoltaic storage direct flexible microgrid, Nm is the number of distributed photovoltaic device nodes, represents the observed value of the average bus voltage corresponding to all distributed energy storage device nodes by the i-th distributed energy storage device node, V represents the observed value of the average bus voltage corresponding to all distributed energy storage device nodes received by node j in the full-duplex communication network, i represents the measured value of the bus voltage corresponding to the i-th distributed energy storage device node, and Respectively and V i The first-order differential operation of ij represents the communication link weight between node i and node j. When there is data interaction between nodes i and j, a ij > 0, otherwise a ij = 0. It should be noted that the DC bus average voltage output by the average voltage observer of the above distributed energy storage device node will be used as the input reference signal of the bus voltage controller.

[0046] like Figure 4 As shown, in an embodiment applicable to the present 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 "distributed coordination controller of energy storage nodes" in the above is the coordination controller configured for each converter of the distributed energy storage device. In another embodiment of the present application, the coordination controller of the distributed energy storage device node and the distributed photovoltaic device node uses 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. The average voltage observer of the distributed photovoltaic device node observes the average voltage of the DC bus corresponding to the distributed energy storage device node based on the following average voltage observation algorithm:

[0047]

[0048] in, represents the observed value of the average bus voltage of all energy storage device nodes in the photovoltaic and energy storage direct flexible microgrid by the kth distributed photovoltaic device node, a kj Represents the weight of the communication link between node k and node j.

[0049] Step S104: Based on the interaction of real-time status information between adjacent nodes in 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 achieve 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 achieve power balance of the DC microgrid and adjust the proportion of photovoltaic power supply in the total load demand.

[0050] like Figure 3 As shown, it is a schematic diagram that any energy storage device node is configured with a corresponding coordination controller in an embodiment applicable to the present application, and each coordination controller includes an average voltage observer and a bus voltage controller. The coordination controller corresponding to the distributed energy storage device node and the distributed photovoltaic device node uses a 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 real-time interactive average voltage estimation value. It can be: the average voltage observer of the distributed energy storage device node observes 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 present application, based on the interaction of real-time status information between adjacent nodes in a 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 achieve 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 by the voltage deviation parameter to achieve the average voltage of the corresponding bus being stable at the rated value:

[0053]

[0054]

[0055]

[0056]

[0057]

[0058] Among them, u i is the control signal output by the coordination controller of the i-th distributed energy storage device node to the corresponding converter, V rat Indicates 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 They represent the droop control current and voltage correction of the i-th distributed energy storage device node, is the status information received by the i-th distributed energy storage device node from the neighboring node, the neighboring node includes a distributed energy storage device node or a distributed photovoltaic device node, represents the output current per unit value of the i-th distributed energy storage device node, represents the bus voltage zeroing reference value of the i-th distributed energy storage device node, 1 m represents a unit vector of dimension m, represents the maximum output current of the distributed photovoltaic device node, θ∈[0,1] is the voltage deviation coefficient in the coordinated 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 their respective maximum values, ω>0 is the output ratio coefficient, the smaller ω is, the greater the photovoltaic output is, the less abandoned light is, the larger ω is, the smaller the photovoltaic output is, the more abandoned light is, represents the admittance matrix of the photovoltaic-storage direct-flexible microgrid, is a real diagonal matrix, the diagonal elements represent the equivalent admittance of the load, Y+Y L It is expressed as a block matrix:

[0059]

[0060]

[0061]

[0062] like Figure 4 As shown, in an embodiment applicable to the present 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. The coordination controller corresponding to the distributed energy storage device node and the distributed photovoltaic device node uses 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. It can be: the average voltage observer of the distributed photovoltaic device node observes the average voltage of the DC 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 uses the photovoltaic node distributed coordination control algorithm to achieve power balance of the DC microgrid and adjust the proportion of photovoltaic power supply in the total load demand, including: for the distributed photovoltaic device node, the following bus voltage control law is used to achieve that the ratio of the output current of each distributed photovoltaic device node is equal to the rated output current of each node:

[0065]

[0066]

[0067]

[0068] Among them, u k is the control signal output by the coordination controller of the kth distributed photovoltaic device node to the corresponding converter, is the status information received by the kth distributed photovoltaic device node from the neighbor node. The neighbor node can be a distributed energy storage device node or a distributed photovoltaic device node. represents the per unit output current of the kth distributed photovoltaic device node, represents the droop control current correction value 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 may also 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 DC bus in the photovoltaic storage direct flexible microgrid, 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, wherein the value range of the voltage deviation coefficient θ in the coordination controller is θ∈[0,θ d ], and θ d It can be solved according to the following formula:

[0070]

[0071] Where ΓV is the maximum voltage deviation allowed by the DC bus in the photovoltaic and energy storage direct-current flexible microgrid, Ψ = [ψ1, ψ2, …, ψ N ] T is an intermediate variable and has no actual physical meaning. Indicates 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 proportional coefficient ω is determined by the following calculation formula:

[0073]

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

[0075] like Figure 5 As shown, it is a bus voltage simulation waveform of a simulation example of an embodiment of the present application under normal operation, and the system rated voltage V rat =380V, the allowed bus voltage range of the distributed energy storage device node is [372.4,387.6], such as Figure 6 As shown in the figure, the per-unit simulation waveform of the output current of each node is shown. This simulation example is divided into four stages:

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

[0077] Phase 2, t∈[5,10)s, set the parameters θ=0.63, ω=2 in the coordination controller of the distributed energy storage device nodes. In this phase, the bus voltages of all distributed energy storage device nodes are within the allowable range, the output current per unit values ​​of all distributed photovoltaic device nodes remain consistent, and the output current per unit values ​​of the distributed photovoltaic device nodes are no longer consistent;

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

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

[0080] By adjusting θ, the bus voltage of the distributed energy storage device node is effectively controlled, and by adjusting ω, the output size of the distributed photovoltaic device node is controlled.

[0081] from Figure 1 From the example of the classified coordinated control method of the photovoltaic-storage direct-flexible microgrid, it can be seen that, on the one hand, the classified distributed regulation method adopted in this application not only fully utilizes the voltage stability and power regulation capabilities of the distributed energy storage equipment, but also incorporates the power generation of photovoltaic equipment into the regulation range, thereby enhancing the elasticity of the system, improving the system's ability to absorb photovoltaic power generation, and alleviating the excessive demand for the regulation capabilities of distributed energy storage equipment; on the other hand, the classified coordinated control method proposed in this application is implemented in a distributed form, and only requires the establishment of a unified full-duplex communication network between the photovoltaic device nodes and the energy storage device nodes. The data transmitted in the communication network is unified, which is applicable to both photovoltaic devices and energy storage devices, and can achieve the classified coordinated control goals of photovoltaic devices and energy storage devices.

[0082] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application is described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the above embodiments, or replace some of the technical features therein by equivalents; 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 implementation methods described above further describe the purpose, technical solutions and beneficial effects of the present application in detail. It should be understood that the above description is only the specific implementation method of the present application, and is not used to limit the protection scope of the present application. Any modifications, equivalent replacements, improvements, 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 classification coordination control method for a photovoltaic-storage direct-flexible microgrid, characterized in that: The photovoltaic storage direct flexible microgrid includes a plurality of distributed photovoltaic devices and distributed energy storage devices, and the method includes: Each of the multiple distributed photovoltaic devices and distributed energy storage devices in the photovoltaic-storage direct-current microgrid is connected to the DC microgrid through its own converter, and each of the converters is configured with a coordination controller; Establishing a full-duplex communication network between the plurality of coordination controllers, wherein the full-duplex communication network includes distributed photovoltaic device nodes and distributed energy storage device nodes; The coordination controller of the distributed energy storage device node and the distributed photovoltaic device node utilizes the full-duplex communication network to observe the average bus voltage corresponding to the distributed energy storage device node through real-time interactive average voltage estimation value; Based on the interaction of real-time status information between adjacent nodes in the full-duplex communication network, the coordination controller of the distributed energy storage device node utilizes the distributed coordination control algorithm of the energy storage node to achieve voltage stability of the bus where the distributed energy storage device node is located. The coordination controller of the distributed photovoltaic device node utilizes the distributed coordination control algorithm of the photovoltaic node to achieve power balance of the DC microgrid and adjust the proportion of photovoltaic power supply in the total load demand.

2. The classification coordination control method of the photovoltaic storage direct flexible microgrid according to claim 1 is characterized in that: The coordination controller of the distributed energy storage device node includes an average voltage observer; The coordinated controller of the distributed energy storage device node and the distributed photovoltaic device node utilizes 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 interactive average voltage estimation value, including: the average voltage observer of the distributed energy storage device node observes the average voltage of the DC bus corresponding to the distributed energy storage device node based on the following average voltage observation algorithm: Among them, the represents the observed value of the average bus voltage corresponding to all distributed energy storage device nodes by the i-th distributed energy storage device node, V represents the observed value of the average bus voltage corresponding to all distributed energy storage device nodes received by node j in the full-duplex communication network, i represents the measured value of the bus voltage corresponding to the i-th distributed energy storage device node, and Respectively and V i The first-order differential operation of ij Represents the weight of the communication link between node i and node j.

3. The classification coordination control method of the photovoltaic storage direct flexible microgrid according to claim 2 is characterized in that: The coordination controller of the distributed energy storage device node includes a bus voltage controller; Based on the interaction of real-time status information between adjacent nodes in the full-duplex communication network, the coordinated controller of the distributed energy storage device node uses the distributed coordinated control algorithm of the energy storage node to achieve voltage stability of the bus where the distributed energy storage device node is located, including: for the distributed energy storage device node, the following bus voltage control law is adopted and the bus voltage deviation is adjusted by the voltage deviation parameter to achieve the average voltage of the corresponding bus being stable at the rated value: Among them, the u i is the control signal output by the coordination controller of the i-th distributed energy storage device node to the corresponding converter, and the V rat represents the rated value of the DC microgrid 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 They represent the droop control current and voltage correction of the i-th distributed energy storage device node, is the status information received by the i-th distributed energy storage device node from the neighboring node, the neighboring node includes a distributed energy storage device node or a distributed photovoltaic device node, represents the output current per unit value of the i-th distributed energy storage device node, represents the bus voltage zeroing reference value of the i-th distributed energy storage device node, the 1 m represents a unit vector of dimension m, represents the maximum output current of the distributed photovoltaic device node, the θ∈[0,1] is the voltage deviation coefficient in the coordinated controller of the distributed energy storage device node, the ω>0 is the output proportional coefficient, the represents the admittance matrix of the photovoltaic-storage direct-flexible microgrid, is a real diagonal matrix, the diagonal elements represent the equivalent admittance of the load, Y+Y L It is expressed as a block matrix:

4. The classification coordination control method of the photovoltaic storage direct flexible microgrid according to claim 1 is characterized in that: The coordination controller of the distributed photovoltaic device node includes an average voltage observer; The coordinated controller of the distributed energy storage device node and the distributed photovoltaic device node utilizes the 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, including: the average voltage observer of the distributed photovoltaic device node observes the average voltage of the DC bus corresponding to the distributed energy storage device node based on the following average voltage observation algorithm: in, represents the observed value of the average bus voltage of all energy storage device nodes in the photovoltaic and energy storage direct flexible microgrid by the kth distributed photovoltaic device node, a ki Represents the weight of the communication link between node k and node j.

5. The classification coordination control method of the photovoltaic storage direct flexible microgrid according to claim 4 is characterized in that: The coordination controller of the distributed photovoltaic device node includes a bus voltage controller; The coordinated controller of the distributed photovoltaic device node uses a distributed coordinated control algorithm for photovoltaic nodes to achieve power balance of the DC microgrid and adjust the proportion of photovoltaic power supply in the total load demand, including: for the distributed photovoltaic device nodes, the following bus voltage control law is used to achieve that the ratio of the output current of each distributed photovoltaic device node is equal to the rated output current of each node: Among them, the u k is the control signal output by the coordination controller of the kth distributed photovoltaic device node to the corresponding converter, is the status information received by the kth distributed photovoltaic device node from a neighboring node, where the neighboring node may be a distributed energy storage device node or a distributed photovoltaic device node. represents the per unit output current of the kth distributed photovoltaic device node, represents the droop control current correction value of the kth distributed photovoltaic device node, the 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.

6. The classification coordination control method of the photovoltaic storage direct flexible microgrid according to claim 3 is characterized in that: The method also includes: 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 DC bus in the photovoltaic storage direct flexible microgrid, 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.

7. The classification coordination control method of the photovoltaic storage direct flexible microgrid according to claim 6 is characterized in that: The voltage deviation coefficient θ has a value range of θ∈[0,θ d ], the θ d Solve according to the following formula: Among them, the Γ V is the maximum voltage deviation allowed by the DC bus in the photovoltaic storage direct-flexible microgrid, and the Ψ=[ψ1,ψ2,…,ψ N ] T is an intermediate variable, Indicates the rated maximum output current of the distributed energy storage device node.

8. The classification coordination control method of the photovoltaic storage direct flexible microgrid according to claim 6 is characterized in that: For a given voltage deviation coefficient θ, the adjustable range of the output proportional coefficient ω is determined by the following calculation formula: Among them, the The ζ i and v i It is an intermediate variable in the calculation process.

9. The classification coordination control method of the photovoltaic storage direct-flexible microgrid according to any one of claims 1 to 8, characterized in that: The establishing of a full-duplex communication network between the plurality of coordination controllers comprises: Based on the proximity principle, a sparse full-duplex communication network is established between the multiple coordination controllers.

10. The classification coordination control method of the photovoltaic storage direct flexible microgrid according to claim 9 is characterized in that: The method of establishing a sparse full-duplex communication network among the plurality of coordination controllers based on the proximity principle includes: establishing a sparse self-organizing full-duplex communication network among the plurality of coordination controllers based on the proximity principle.

Images