Direct current microgrid distributed flexible control system

Abstract

The application discloses a kind of direct current microgrid distributed flexible control systems, including multiple power supply nodes, each power supply node is in communication network with neighbor power supply node by wired and / or wireless communication;Each power supply node includes the collaborative controller of primary controller and secondary controller group;Secondary controller includes communication link attack compensator;Secondary controller is used to generate voltage reference signal according to the state signal of the power supply node and neighbor power supply node in communication network and communication link attack compensation signal;Primary controller according to voltage reference signal and the measurement signal of the converter output current of the power supply node, to the converter controller output control signal;Converter controller is used to convert control signal into PWM signal and send to converter, to realize the control of bus voltage.Direct current microgrid distributed flexible control system can be under unknown communication link attack, completely restore direct current microgrid voltage regulation and accurate power allocation control target.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of direct current micro-grid control, and particularly relates to a distributed flexible control system of a direct current micro-grid. BACKGROUND

[0002] The direct current micro-grid is a micro-grid with direct current characteristics, which effectively integrates distributed renewable energy power generation devices, energy storage devices and direct current loads, realizes local consumption of green energy, and thus improves energy utilization efficiency. The distributed power supply node is integrated into the direct current micro-grid by using a converter as an access device. The output of each distributed power supply, i.e. the output voltage and current, is reasonably controlled. The distributed control system of the direct current micro-grid facing the converter is a key device for ensuring stable and normal operation of the direct current micro-grid.

[0003] The droop control method is the most common decentralized cooperative control method. When there is no communication between power supply nodes and the transmission line impedance can be ignored, the distributed power supplies can work cooperatively. However, when the transmission line impedance between the power supplies in the micro-grid cannot be ignored, the accuracy of power distribution achieved by only using the droop control method will be reduced.

[0004] The secondary cooperative controller based on the consensus algorithm is used to compensate the droop control method, effectively overcoming the influence of the transmission line on power distribution. However, when the currently adopted secondary controller is attacked by a network attack, the transmitted information is intentionally tampered with by the attack signal, and further penetrates into the entire micro-grid through the communication link, resulting in uncontrolled power distribution and failure to achieve the purpose of cooperative control to achieve voltage regulation and power distribution. SUMMARY

[0005] In view of the above problem of uncontrolled power distribution under communication link attack, a distributed flexible control system of a direct current micro-grid is provided. The system can alleviate the influence of unknown attack signals under communication link attack, and achieve the control goal of restoring micro-grid power distribution and voltage regulation.

[0006] To solve the above technical problems, one technical solution adopted by the present application is to provide a distributed flexible control system of a direct current micro-grid, characterized in that the system comprises: a plurality of power supply nodes, each of which is in wired and / or wireless communication with neighbor power supply nodes in a communication network;

[0007] Each of the power supply nodes comprises a cooperative controller composed of a primary controller and a secondary controller; the secondary controller comprises a communication link attack compensator;

[0008] The secondary controller is configured to generate a voltage reference signal according to a communication link attack compensation signal of a communication link attack compensator, a state signal of the secondary controller of a neighboring power node of the power node where the secondary controller is located, and a state signal of the power node where the secondary controller is located;

[0009] The primary controller is configured to output a control signal to the converter controller according to a measurement signal of the converter output current of the power node where the primary controller is located, and the voltage reference signal; the converter controller is configured to convert the control signal into a PWM signal and send the PWM signal to the converter; and the converter is configured to control the bus voltage according to the PWM signal.

[0010] The communication link attack compensator is configured to determine a communication link attack compensation signal according to the following expression:

[0011]

[0012] wherein, represents the communication link attack compensation signal of the power node ; represents a compensation signal gain of the power node , when the power node is subjected to a communication link attack, , otherwise, ; represents a time factor, represents a micro-variable with the time factor as a variable; represents a constant factor, ; represents a state error signal of the power node .

[0013] In one of the embodiments, the primary controller is configured to determine the control signal of the converter controller according to the following expression:

[0014]

[0015] wherein, represents the control signal of the converter controller of the power node ; represents the voltage reference signal of the input power node , the voltage reference signal being from an output of the secondary controller; represents a measurement signal of the converter output current of the power node ; is a droop coefficient, the value of the droop coefficient being set according to the following expression:

[0016]

[0017] wherein, is a normal number, represents the output current rating of the power supply node .

[0018] In one embodiment, the secondary controller comprises:

[0019] a state error observer configured to generate the state error signal of the power supply node of interest based on state variables of the power supply node of interest and neighboring power supply nodes in the communication network;

[0020] the communication link attack compensator is configured to generate the communication link attack compensation signal based on whether the communication link of the power supply node of interest is under a false data injection attack and the state error signal of the power supply node of interest;

[0021] a state error corrector configured to generate a state error correction signal of the power supply node of interest based on the state error signal output by the state error observer and the communication link attack compensation signal output by the communication link attack compensator;

[0022] a voltage regulator configured to generate a voltage regulation signal based on a nominal operating voltage of the DC microgrid and a bus voltage measurement signal output by the inverter of the power supply node of interest;

[0023] a reference voltage generator configured to generate the voltage reference signal of the power supply node of interest based on the state error correction signal output by the state error corrector and the voltage regulation signal output by the voltage regulator

[0024] In one embodiment, the state error observer is configured to determine the state error signal of the power supply node of interest and the neighboring power supply nodes in the communication network based on the following expression:

[0025]

[0026] wherein, represents the state error signal of the power supply node ; and are the state variables of the power supply node and the power supply node , respectively; is a communication line gain from the power supply node to the power supply node , if there is a state variable from the power supply node to the power supply node transmission, then , else .

[0027] In one of the embodiments, at the same time, only one of the communication links of the power nodes is directly attacked by the false data injection attack, and the rest of the power nodes are disturbed by the state variable transmission of the attacked power nodes.

[0028] In one of the embodiments, the state error corrector is configured to determine the state error correction signal according to the following expression:

[0029]

[0030] wherein, denotes the state error correction signal of the power node ; denotes the state error signal of the power node ; denotes the communication link attack compensation signal of the power node .

[0031] In one of the embodiments, the voltage regulator is configured to determine the voltage regulation signal according to the following expression:

[0032]

[0033] wherein, denotes the voltage regulation signal of the power node ; denotes the rated operating voltage of the DC microgrid; denotes the corresponding bus voltage measurement signal of the power node ; denotes the gain of the voltage regulation signal of the power node , when the power node is allowed to access the rated operating voltage, , otherwise, .

[0034] In one of the embodiments, the reference voltage generator is configured to determine the voltage reference signal according to the following expression:

[0035]

[0036] wherein, denotes the voltage reference signal of the power node ; denotes the rated operating voltage of the DC microgrid; a voltage regulation signal of the power supply node ; a state error correction signal of the power supply node a state error correction signal of the power supply node a communication line gain from the power supply node to the power supply node if there is a transmission of the state error correction signal , otherwise ;

[0037] In one embodiment, under the false data injection attack, the communication link of the DC microgrid controls all power supply nodes to simultaneously restore the voltage regulation function and the accurate current distribution function through the primary controller and the secondary controller of each power supply node, i.e.

[0038]

[0039] wherein, a corresponding bus voltage measurement signal of the power supply node ;

[0040]

[0041] wherein, a measurement signal of the inverter output current of the power supply node ; an output current rating of the power supply node .

[0042] In one embodiment, the communication mode between the neighboring power supply nodes in the communication network adopts a full-duplex mode and / or a simplex mode.

[0043] However, the currently adopted secondary controller suffers from network attacks, and the transferred information is intentionally tampered with by the attack signal, and further penetrates into the entire microgrid through the communication link, resulting in uncontrolled power distribution and failure to achieve the purpose of coordinated control to achieve voltage regulation and power distribution.

[0044] Compared with the prior art, the present application has the following advantages:

[0045] ​​​​​​​​​​1. The application adopts a completely distributed cooperative control scheme, so that the scale of the system is not limited, and the hot plug of the power supply node is supported.

[0046] 2. The application realizes the control target of recovering voltage regulation and power distribution under unknown communication link attack by improving the secondary controller.

[0047] 3. The DC microgrid distributed flexible control system involved in the embodiment of the application contains a communication link attack compensation term, and through the adjustment of the local attack compensation term, the accurate power distribution and voltage regulation of multiple distributed power supplies in the DC microgrid can be recovered at the same time.

[0048] 4. The embodiment of the application does not involve prior knowledge of the communication link attack signal, and covers the cascading interference suffered by the neighbor power supply node due to the state variable transmission of the attacked power supply node, so that the flexible cooperative controller is more in line with the actual application requirements. BRIEF DESCRIPTION OF DRAWINGS

[0049] Figure 1 It is a schematic diagram of the DC microgrid distributed cooperative control according to an embodiment of the application, wherein the communication network exists network attack interference;

[0050] Figure 2 It is a schematic diagram of the DC microgrid according to an embodiment of the application, wherein the communication network exists network attack interference;

[0051] Figure 3 It is a schematic diagram of the DC microgrid distributed flexible control system and its connection mode according to an embodiment of the application;

[0052] Figure 4 It is a schematic diagram of the DC microgrid voltage and current distributed flexible control system according to an embodiment of the application;

[0053] Figure 5 It is a schematic diagram of the tracking error of the attack compensation term to the unknown attack signal according to an embodiment of the application. DETAILED DESCRIPTION

[0054] The embodiments of the application will be further and more clearly explained in combination with the accompanying drawings. It should be noted that the use occasions of the controller involved in the application are not limited to the embodiments, and for different DC microgrid structures, the controller involved in the application can be applied, and accordingly, it should also be included in the protection scope of the application.

[0055] As shown in the drawings, Figure 1 Figure 1 ​Fig. 1 is a schematic diagram of a DC microgrid distributed cooperative control according to an embodiment of the present application, in which the communication network is interfered by network attacks. In the figure, the DC microgrid electrical network can contain multiple DC buses, and the electrical network topology and load type are not limited, and are applicable to the DC microgrid distributed resilient control system described in the present application. The DC microgrid distributed resilient control system shown in the present application includes multiple power source nodes.

[0056] The distributed power sources in the microgrid are represented in the figure as a structure of battery elements, converters, and output filter cascades. In actual implementation, the power source nodes can be various distributed new energy devices, such as wind power devices, photovoltaic devices, energy storage units, and other devices capable of outputting electrical energy. According to actual output needs, the converter can be a DC-DC converter, an AC-DC converter, etc. It should be noted that the devices that the local controller and other power source nodes in the distributed power source should have are not specifically drawn in the figure. Figure 1

[0057] The cooperative controller of each distributed power source can include a primary controller and a secondary controller. The input signals of the primary controller can include two signals, one from the voltage reference signal output by the secondary controller and the other from the output current measurement signal of the converter of the power source node. The output of the primary controller is used as the instruction signal of the local controller to directly control the output voltage of the converter of the power source node.

[0058] The secondary controller is used to generate a voltage reference signal according to the state signal of the power source node and the secondary controllers of the neighbor power source nodes in the communication network.

[0059] The primary controller is used to output a control signal to the converter controller according to the measurement signal of the output current of the converter of the power source node and the voltage reference signal. The converter controller is used to convert the control signal into a PWM signal and send it to the converter. The converter is used to control the bus voltage according to the PWM signal.

[0060] The input signals of the secondary controller include the state information of the neighbor power source nodes transmitted through the communication network and the measurement signal of the output voltage of the converter of the power source node. The input of the primary controller includes the voltage reference signal output by the secondary controller and the measurement signal of the output current of the converter of the power source node.

[0061] In the specific implementation process, Figure 1 The communication network connection shown in the figure can adopt wired communication and / or wireless communication. The communication mode between the neighbor power source nodes can adopt a full-duplex mode or a simplex mode. In the communication network, it is not necessary to establish a connection between any two power source nodes. Only the communication network topology needs to be strongly connected and a balanced graph.

[0062] ​Wherein, the strong connectivity and the balanced graph belong to the concept in the graph theory, the strong connectivity graph is that there is a directed communication path between any power supply node and the rest of the power supply nodes. The balanced graph is that any power supply node has limited input communication line and output communication line, and the number of the input communication line and the output communication line is equal.

[0063] As shown in the figure, Figure 2 Figure 2 It is a schematic diagram of the direct current micro grid according to one embodiment of the present application, wherein the communication network exists the interference of network attack. Figure 2 The figure contains 6 power supply nodes and 6 loads, it should be noted that the application range of the present application is not limited to this embodiment. This embodiment contains any number of power supply loads and any topology of the direct current micro grid, which is suitable for the present application. In addition, Figure 2 The figure only represents the electrical network topology of the physical layer and the communication network topology of the communication layer, and the upper layer controller of the control layer such as the primary controller and the secondary controller is not explicitly shown in each distributed power supply, which should be contained in the implementation process.

[0064] Figure 2 The communication network topology shown in the figure is a ring connection, in the actual implementation process, the communication network topology is not limited to the ring connection mode, as long as the communication network is connected if the cooperative controller of the distributed power supply is connected through the duplex communication network based on the undirected graph, that is, there is a communication path between any two power supply nodes. If the communication network topology is connected through the simplex communication network based on the directed graph, the communication network should be strongly connected and balanced.

[0065] As shown in the figure, Figure 3 Figure 3 It is a schematic diagram of the distributed elastic control system block diagram of the direct current micro grid and the connection mode according to one embodiment of the present application. In this embodiment, the direct current micro grid contains the physical layer, the communication layer and the control layer. The primary control of the cooperative controller of the distributed power supply adopts droop control to realize.

[0066] The control law of the droop control in this embodiment is shown in the following formula:

[0067]

[0068] Wherein, The converter controller control signal of the power supply node The voltage reference signal Is the output of the secondary controller in the power supply node The input signal of the secondary controller can include the bus voltage measurement And the state variable Of the neighbor power supply node. The voltage reference signal ​​It is transmitted to the local power node through the communication network.

[0069] The droop coefficient is set according to the following formula:

[0070]

[0071] in, For positive integers, Indicates power node The rated output current.

[0072] like Figure 4 As shown, Figure 4 This is a schematic diagram of a distributed resilient control system for DC microgrid voltage and current according to an embodiment of the present invention. In this embodiment, the secondary controller may include five parts: a state error observer, a communication link attack compensator, a state error corrector, a voltage regulator, and a reference voltage generator.

[0073] The state error corrector generates a state error correction signal for the power node where it resides, based on the state error signal output by the state error observer and the communication link attack compensation signal output by the communication link attack compensator. The state error observer can observe the weighted sum of the state errors of its own power node and neighboring power nodes, including the weighting coefficients. For neighboring power nodes To power node The communication line gain when a communication connection exists. ,otherwise .

[0074] The communication link attack compensator is used to generate a communication link attack compensation signal based on whether the communication link of the power node is subjected to an erroneous data injection attack and the state error signal of the power node.

[0075] The state error corrector is used to generate a state error correction signal for the power node it is located in, based on the state error signal output by the state error observer and the communication link attack compensation signal output by the communication link attack compensator.

[0076] The voltage regulator is used to generate a voltage regulation signal based on the rated operating voltage of the DC microgrid and the measured bus voltage output signal from the converter of the power node.

[0077] The reference voltage generator is used to generate a voltage reference signal for the power node based on the state error correction signal output by the state error corrector and the voltage regulation signal output by the voltage regulator.

[0078] In the embodiment, the secondary controller of the power supply node includes five parts, i.e., a state error observer, a communication link attack compensator, a state error corrector, a voltage regulator and a reference voltage generator, so that the control target of recovering voltage regulation and accurate power distribution can be achieved under unknown communication link attacks. The distributed resilient control system includes a communication link attack compensation term, and accurate power distribution and voltage regulation of multiple distributed power supplies in the DC micro-grid can be recovered by adjusting the local attack compensation term.

[0079] In an embodiment, at the same time, only the communication link of one power supply node is directly attacked by false data injection, and the rest of the power supply nodes are disturbed by the state variable transmission of the attacked power supply node. In the embodiment, the distributed resilient control system of the DC micro-grid provided by the application can meet the control requirements when only the communication link of one power supply node is directly attacked by false data injection, and accurate power distribution and voltage regulation of multiple distributed power supplies in the DC micro-grid can be recovered by adjusting the local attack compensation term, so that the resilient cooperative controller is more in line with the actual application requirements, and the stability and availability of the distributed resilient control system of the DC micro-grid can be improved.

[0080] In an embodiment, the state error observer is configured to determine the state error signal of the local power supply node and the neighbor power supply node in the communication network according to the following expression:

[0081]

[0082] wherein, denotes the state error signal of the power supply node . and are state variables of the power supply node and the power supply node , respectively; is the communication line gain from the power supply node to the power supply node , if the power supply node transmits the state variable to the power supply node , then , otherwise .

[0083] In the embodiment, the state error corrector can correct the observed state error by using the communication link attack compensation signal, so as to provide a more accurate state error signal, and the DC micro-grid voltage and current distributed resilient control system has more stable and excellent performance.

[0084] In an embodiment, the state error corrector is configured to determine the state error correction signal according to the following expression:

[0085]

[0086] wherein, represents the state error correction signal of the power supply node ; represents the state error signal of the power supply node ; represents the communication link attack compensation signal of the power supply node .

[0087] In the embodiment, the communication link attack compensation signal of the power supply node is added to the state error signal to obtain the state error correction signal, which corrects for the unknown communication link attack and makes the voltage reference signal generated by the reference voltage generator more accurate, thereby achieving voltage regulation of multiple distributed power supplies in the DC microgrid.

[0088] The communication link attack compensator can compensate for all unknown communication link attacks on the power supply node using local data, without the need to accurately extract the parameters of the network attack signal of the error data injection attack, as shown in the following expression:

[0089]

[0090] wherein, represents the communication link attack compensation signal of the power supply node ; represents the compensation signal gain, when the power supply node is subjected to a communication link attack, , otherwise, ; represents the time factor, represents a micro-variable with the time factor as the variable; represents the constant factor, ; represents the state error signal of the power supply node .

[0091] Compared with the prior art, the embodiment of the application adopts a completely distributed cooperative control scheme, so that the scale of the system is not limited, and the hot plug of the power supply node can be supported. The secondary controller of the power supply node is also improved, so that the control target of completely restoring voltage regulation and power distribution can be achieved under unknown communication link attacks. At the same time, the distributed elastic control system involved in the embodiment of the application contains a communication link attack compensation term, and by adjusting the local attack compensation term, the accurate power distribution and voltage regulation of multiple distributed power supplies in the direct current micro-grid can be restored at the same time. Moreover, the embodiment of the application does not involve prior knowledge of the communication link attack signal, can cover the adjacent power supply nodes suffering from chain interference due to the state variable transmission of the attacked power supply node, so that the elastic cooperative controller is more in line with the application requirements in actual implementation.

[0092] In an embodiment, the reference voltage generator generates a reference voltage signal for the primary controller, which is obtained by summing and integrating the outputs of the state error observer and the voltage regulator, as shown in the following formula:

[0093]

[0094] wherein, represents the voltage reference signal of the power supply node ; represents the rated operating voltage of the direct current micro-grid; represents the voltage regulation signal of the power supply node ; and are state error correction signals of the power supply node and the power supply node , respectively; is the communication line gain from the power supply node to the power supply node , if there is a transmission of the state error correction signal from the power supply node to the power supply node , then , otherwise ; represents a time factor, represents a micro-variable with the time factor as a variable; n is a non-negative integer.

[0095] It is worth noting that the integrators involved in the present application can be replaced by PID controllers (Proportion Integration Differentiation). A PID controller is composed of a proportional unit (P), an integral unit (I) and a differential unit (D) through the setting of three parameters Kp, Ki and Kd. PID controllers can be applied to systems that are substantially linear and whose dynamic characteristics do not change over time. PID controllers compare the data collected with a reference value and then use the difference to calculate a new input value, which aims to bring the system data to or maintain it at the reference value. The input value can be adjusted according to the historical data and the occurrence rate of the difference, so that the system is more accurate and stable.

[0096] In an embodiment, the communication link of the DC microgrid under the error data injection attack, through the primary controller and the secondary controller of each power supply node, controls all power supply nodes to simultaneously restore the voltage regulation function and the accurate current distribution function, i.e.,

[0097]

[0098] wherein, represents the power supply node corresponding to the bus voltage measurement signal, ; represents the rated operating voltage of the DC microgrid;

[0099]

[0100] wherein, represents the power supply node the converter output current measurement signal of, ; represents the output current rated value of the power supply node .

[0101] In an embodiment, the voltage regulator is used to achieve the weighted value of the difference between the local bus voltage and the rated voltage, and the weighting coefficient is the voltage regulation signal gain, when the power supply node allows access to the rated operating voltage, , otherwise, .

[0102] The voltage regulator can be configured to determine the voltage regulation signal according to the following expression:

[0103]

[0104] wherein, represents the power supply node​ a voltage regulation signal; represents a rated operating voltage of the DC microgrid; represents a power supply node a corresponding bus voltage measurement signal; represents a gain of the voltage regulation signal, when the power supply node allows access to the rated operating voltage, otherwise, .

[0105] In the embodiment, the voltage regulator is capable of outputting a corresponding voltage regulation signal according to the rated operating voltage of the DC microgrid, the power supply node a corresponding bus voltage measurement signal, and a gain of the voltage regulation signal, thereby achieving automatic regulation of the output voltage of the multiple distributed power supplies in the DC microgrid and improving the stability of the distributed elastic control system of the DC microgrid.

[0106] As Figure 5 shown, Figure 5 the tracking error of the attack compensation term to the unknown attack signal according to one embodiment of the application. The tracking error of the attack compensation term to the unknown attack signal shown in the embodiment can be used for comparison with Figure 2 . When all communication links of the power supply node 6 are subjected to unknown error data injection attacks, the entire shaded area in the figure can be regarded as communication data being disturbed by network attacks. In order to show the effect of the attack compensation term tracking the unknown attack signal, the equivalent amplitude of all communication link attack signals suffered by the power supply node 6 can be artificially analyzed.

[0107] As Figure 5 shown by the unknown attack signal curve, Figure 5 the tracking error signal curve in the figure converges to 0 at time 8 seconds and maintains stability, which indicates that the attack compensation term provided by the application can track the unknown attack signal in real time. The DC microgrid system in the embodiment can completely recover the control target of voltage regulation and power distribution under unknown communication link attacks.

Claims

1. A DC microgrid distributed flexible control system, characterized in that, The system comprises: a plurality of power supply nodes, each of the power supply nodes being in wired and / or wireless communication with neighbor power supply nodes in a communication network; Each of the power supply nodes comprises a cooperative controller composed of a primary controller and a secondary controller; the secondary controller comprises a communication link attack compensator; The secondary controller is configured to generate a voltage reference signal according to a communication link attack compensation signal of the communication link attack compensator, a state signal of the secondary controller of the power supply node where the secondary controller is located, and neighbor power supply nodes in the communication network; The primary controller is configured to output a control signal to a converter controller according to a measurement signal of a converter output current of the power supply node where the primary controller is located and the voltage reference signal; the converter controller is configured to convert the control signal into a PWM signal and send the PWM signal to the converter; the converter is configured to control a bus voltage according to the PWM signal; The state error correction signal is determined according to the following expression: wherein, represents the state error correction signal for the power node ; represents the state error signal for the power node ; represents the communication link attack compensation signal for the power node ; The voltage reference signal is determined according to the following expression: wherein represents a voltage reference signal of a power supply node ; represents a rated operating voltage of the direct current micro-grid; represents a voltage regulating signal of a power supply node ; and are the state error correction signals of the power supply node and the power supply node , respectively; is a communication line gain from the power supply node to the power supply node , if there is a transmission of the state error correction signal from the power supply node to the power supply node , then , otherwise ; is a non-negative integer; The communication link attack compensator is configured to determine the communication link attack compensation signal according to the following expression: wherein represents the communication link attack compensation signal of the power node ; represents the compensation signal gain of the power node , when the power node is subject to a communication link attack, , otherwise, ; represents a time factor, represents a micro variable in terms of the time factor; represents a constant factor, ; represents the state error signal of the power node .

2. The DC microgrid distributed flexible control system of claim 1, wherein, The primary controller is configured to determine the control signal of the converter controller according to the following expression: wherein represents the control signal of the converter controller of the power supply node ; represents the voltage reference signal of the input power supply node ; represents the measurement signal of the converter output current of the power supply node ; is a droop coefficient, the value of which is set according to the following formula: wherein is a normal number, denotes the output current rating of the power supply node .

3. The DC microgrid distributed flexible control system of claim 1, wherein, The secondary controller comprises: A state error observer configured to generate the state error signal of the power supply node where the state error observer is located according to state variables of the power supply node where the state error observer is located and neighbor power supply nodes in the communication network; The communication link attack compensator is configured to generate the communication link attack compensation signal according to whether the communication link of the power supply node where the communication link attack compensator is located is subjected to a false data injection attack and the state error signal of the power supply node where the communication link attack compensator is located; A state error corrector configured to generate a state error correction signal of the power supply node where the state error corrector is located according to the state error signal output by the state error observer and the communication link attack compensation signal output by the communication link attack compensator; A voltage regulator configured to generate a voltage regulation signal according to a rated operating voltage of a direct-current microgrid and a bus voltage measurement signal output by the converter of the power supply node where the voltage regulator is located; A reference voltage generator configured to generate the voltage reference signal of the power supply node where the reference voltage generator is located according to the state error correction signal output by the state error corrector and the voltage regulation signal output by the voltage regulator.

4. The DC microgrid distributed flexible control system of claim 3, wherein, The state error observer is configured to determine the state error signal of the power supply node where the state error observer is located and neighbor power supply nodes in the communication network according to the following expression: wherein denotes the state error signal of the power supply node ; and denote the state variables of the power supply nodes and , respectively; denotes the state variable of the power supply node ; is the communication line gain from the power supply node to the power supply node , if there is a transmission of the state variable from the power supply node to the power supply node , , otherwise .

5. The DC microgrid distributed flexible control system as claimed in claim 3, wherein, At the same time, only one of the communication links of the power supply nodes is directly subjected to the false data injection attack, and the rest of the power supply nodes are subjected to cascading interference due to the transmission of the state variables of the attacked power supply nodes.

6. The DC microgrid distributed flexible control system of claim 3, wherein, The voltage regulator is configured to determine the voltage regulation signal according to the following expression: wherein represents the voltage regulation signal of the power supply node ; represents the nominal operating voltage of the DC microgrid; represents the voltage regulation signal of the power supply node ; represents the voltage regulation signal of the power supply node with a gain, when the power supply node allows access to the nominal operating voltage, , otherwise, .

7. The DC microgrid distributed flexible control system of claim 6, wherein, The communication link of the direct current micro-grid under the false data injection attack controls all power supply nodes to simultaneously restore the voltage regulation function and the accurate current distribution function through the primary controller and the secondary controller of each power supply node, that is wherein, represents a power supply node corresponding to the bus voltage measurement signal, ; represents the rated operating voltage of the DC microgrid; wherein represents the power supply node a measurement signal of the inverter output current of the power supply node ; represents the output current rating of the power supply node ; .

8. The DC microgrid distributed flexible control system of claim 1, wherein, The communication mode between the neighboring power supply nodes in the communication network adopts a full-duplex mode and / or a simplex mode.

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