AC micro-grid multi-power spring passivity control method under false data attack

Abstract

The invention relates to an AC micro-grid multi-power spring passivity control method under false data attack. The method comprises the following steps: firstly, constructing a multi-power spring consistency control law to obtain an effective value regulating variable of bus voltage of each node of the micro-grid; solving a voltage effective value expected track according to the voltage effective value adjusting quantity; a state variable is selected, and an alternating-current micro-grid bilinear model containing multiple power springs is constructed; obtaining an expected track of the state variable; solving an output variable of the alternating-current micro-grid bilinear model containing the multiple power springs according to the known quantities; and finally, constructing a passivity control law to obtain an output variable of the passivity control law. Generating an SPWM (sinusoidal pulse width modulation) signal for controlling the power spring; and bus voltage fluctuation caused by false data attack is suppressed. Compared with the prior art, the method has the advantages that adverse effects caused by false data injection attacks are effectively suppressed, and the passive control law is simple in form, small in calculation amount and good in dynamic responsiveness.

Description

Technical Field

[0001] The present invention relates to the field of microgrid security technology, and in particular to a method for controlling multiple power springs passivity of an AC microgrid under a false data attack. Background Art

[0002] With the high penetration rate of new energy sources being incorporated into microgrids, power springs can effectively solve the problem of voltage fluctuations in microgrids caused by the intermittency and uncertainty of new energy sources. In order to achieve the coordinated operation of multiple power springs set up in the microgrid system, the consistency control method is generally adopted. By exchanging information with adjacent power spring nodes, the system bus voltage can be coordinated to achieve stable control, which can take into account both communication costs and control performance.

[0003] At present, with the widespread application of microgrids, a large number of sensors and measurement and control devices are connected to microgrids. At the same time, third-party applications can also flexibly access the information system of microgrids through these networks to provide additional services. This convenience of access also means that the information system of microgrids has more potential entry points, which may be maliciously exploited, thereby increasing the risk of microgrids being attacked by network attacks. When the multi-power spring consistency control law of the AC microgrid is attacked by false data injection, the voltage fluctuation suppression performance of the microgrid is difficult to ensure, which seriously threatens the safety of the power system.

[0004] Chinese patent CN113285496B discloses a distributed elastic control method for microgrids based on confidence factors. Based on elastic consistency, a distributed secondary voltage reactive control of the microgrid is established to achieve elastic operation of system reactive power sharing and average voltage recovery. This control method is based on the consistency control of a multi-agent system, taking into account both normal communication scenarios and network attack scenarios, providing a basis for the design of a control structure for distributed secondary control, and thus improving the operational elasticity of the microgrid. However, the control law of this patent is very complex and requires a large amount of calculation, which will cause control delays in microgrid systems that require rapid response, affecting the stability and reliability of the system. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a method for passively controlling multiple power springs of an AC microgrid under a false data attack, so as to effectively suppress the adverse effects caused by the false data injection attack.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] According to one aspect of the present invention, a method for controlling the passivity of multiple power springs in an AC microgrid under a false data attack is provided, and the method steps include:

[0008] S1. Construct a multi-power spring consistency control law under false data injection attack to obtain the effective value regulation of the bus voltage at each node of the microgrid;

[0009] S2, obtaining the expected trajectory of the effective value of the bus voltage at each node of the microgrid by adjusting the effective value of the bus voltage at each node of the microgrid;

[0010] S3, select state variables and construct a bilinear model of AC microgrid with multiple power springs;

[0011] S4, obtaining the expected trajectory of the state variable from the expected trajectory of the effective value of the bus voltage at each node of the microgrid;

[0012] S5. Combining the expected trajectory of the state variable with the state variable to obtain the output variable of the AC microgrid bilinear model containing multiple power springs;

[0013] S6. construct a passive control law, and bring the output variable into the constructed passive control law to obtain the output variable of the passive control law;

[0014] S7. Based on the output variable of the passive control law, an SPWM signal for controlling the working state of the electric spring is generated accordingly to suppress the bus voltage fluctuation caused by the false data attack.

[0015] As a preferred technical solution, the multi-electric spring consistency control law in S1 is:

[0016]

[0017] in, is the coupling coefficient between the effective value of the voltage at the i-th node and the reactive power of the electric spring; a ij is the value of the node (i, j) in the communication network adjacency matrix; g i is the consistency control constraint coefficient; Q ES,i (t), Q ES,j (t) are the reactive power of the electric spring at the i-th node and the j-th node, are the maximum reactive power of the electric spring at the i-th node and the j-th node, Q ES,i,ref is the reactive power reference value of the electric spring at the i-th node.

[0018] Furthermore, the multi-power spring consistency control law, when attacked by false data injection, is:

[0019]

[0020] in, Indicates the time when the false data injection attack occurs; are the reactive power of the electric springs at the i-th node and the j-th node when the false data injection attack occurs; represents the false energy constraint signal injected by the attack; γ i represents the false data injection attack control coefficient when γ i =1, indicating that the multi-power spring consistency control system is attacked by false data injection. i =0, indicating that the multi-power spring consistency control system is not attacked by false data injection.

[0021] The state variables in S3 specifically include the d-axis and q-axis components of the electric spring filter inductor current and the d-axis and q-axis components of the electric spring output voltage.

[0022] As a preferred technical solution, the expected trajectory of the effective value of the bus voltage at each node of the microgrid in S4 is the superposition of the effective value adjustment amount of the bus voltage at each node of the microgrid and the rated value of the bus voltage at each node of the microgrid:

[0023] V i * =V i des +ΔV i (t),

[0024] V i * is the expected trajectory of the effective value of the bus voltage at each node of the microgrid; V i des is the rated value of bus voltage at each node of the microgrid; ΔV i (t) is the effective value regulation of bus voltage at each node of the microgrid.

[0025] As a preferred technical solution, the AC microgrid bilinear model containing multiple power springs in S3 is specifically:

[0026]

[0027] is the x derivative; m d 、m q are the d-axis and q-axis components of the switching quantity of the electric spring converter respectively; i L,d 、i L,q are the d-axis and q-axis components of the electric spring filter inductor current respectively; V ES,d 、V ES,q They are the d-axis and q-axis components of the power spring output voltage respectively;

[0028] System parameter matrix:

[0029]

[0030] The d-axis bilinear matrix of the power spring is:

[0031]

[0032] The q-axis bilinear matrix of the power spring is:

[0033]

[0034] Perturbation matrix:

[0035]

[0036] Among them, C, L f They are the power spring capacitor and filter inductor respectively; V dc,d 、V dc,q are the d-axis and q-axis components of the DC side voltage of the power spring converter respectively; i d 、i q are the d-axis and q-axis components of the microgrid line current respectively; ω is the microgrid angular frequency; a1 is the system impedance ratio.

[0037] Furthermore, the expression of the output variable y of the AC microgrid bilinear model with multiple power springs is:

[0038]

[0039] Where x* is the expected trajectory of the state variable; Δx is the tracking error of the expected trajectory of the state variable, Δx = xx * ; P is a positive definite symmetric matrix.

[0040] Furthermore, the positive definite symmetric matrix P satisfies:

[0041]

[0042] As a preferred technical solution, when constructing the passive control law, the input variables of the AC microgrid bilinear model containing multiple power springs are first defined, including the d-axis and q-axis components of the switching quantity of the power spring converter. The passive control law constructed is specifically:

[0043] Δu=-Ky+u *

[0044] Among them, Δu is the output variable of the passive control law, u* is the expected trajectory of the input variable of the passive control law; K is the proportional coefficient of the passive controller; y is the output variable of the bilinear model.

[0045] Furthermore, the switching value of the power spring converter refers to adjusting the duty cycle of the power spring SPWM signal.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] 1. In the present invention, the output variables of the bilinear model are obtained by combining the effective value adjustment amount of the bus voltage of each node with the constructed bilinear model, and then the output variables of the bilinear model are introduced into the constructed passive control law to obtain the output variables of the passive control law, and then the SPWM signal for controlling the working state of the power spring is generated. The global asymptotic stability of the multi-power spring closed-loop control system of the microgrid under the attack of false data injection can be achieved to the expected working point, and the AC microgrid bus voltage can still be maintained stable under the attack of false data injection, which effectively suppresses the adverse effects caused by the false data injection attack.

[0048] 2. The passive control law constructed by the present invention is: Δu=-Ky+u * The output variable of this control law is simply the output variable of the AC microgrid bilinear model multiplied by a proportional coefficient, plus the result of the expected trajectory of the input variable. The passive control law has a simple form, small amount of calculation, good dynamic responsiveness, can respond quickly and form the expected trajectory, improves the calculation efficiency, and can also save energy consumption and calculation cost.

[0049] 3. The present invention proposes a bilinear model of AC microgrid with multiple power springs, which is jointly determined by the derivative of state variables, the switch quantity of the power spring converter, the system parameter matrix, the power spring bilinear matrix and the disturbance matrix. It can more accurately describe the dynamic behavior of the power spring in the microgrid, prepare conditions for the design of a multi-power spring cooperative passivity controller, thereby increasing the stability and effectiveness of the generated control law. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It is a flow chart of the method for controlling the passivity of multiple power springs in an AC microgrid under false data attack of the present invention;

[0051] Figure 2 It is a schematic diagram of the topological structure of the AC microgrid multi-power spring system under false data attack of the present invention;

[0052] Figure 3 The waveform diagram of each bus voltage obtained by using the method proposed by the present invention in the embodiment;

[0053] Figure 4 This is a reactive power waveform diagram of each electric spring obtained by using the method proposed by the present invention in the embodiment. DETAILED DESCRIPTION

[0054] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0055] Example

[0056] In this embodiment, a method for controlling the passivity of multiple power springs in an AC microgrid under false data attack is applied. Figure 1 shown.

[0057] In this embodiment, the multi-power spring consistency control law under false data injection attack is first constructed to obtain the effective value regulation of the bus voltage at each node of the microgrid; the topological structure of the AC microgrid multi-power spring system under false data attack is as follows: Figure 2 shown.

[0058] Each power spring uses the communication network to exchange reactive power information with adjacent nodes to obtain the effective value adjustment value ΔV of the bus voltage at each node of the microgrid. i (t), the multi-electric spring consistency control law is designed as:

[0059]

[0060] in, is the coupling coefficient between the effective value of the voltage at the i-th node and the reactive power of the electric spring; a ij is the value of the node (i, j) in the communication network adjacency matrix; g i is the consistency control constraint coefficient; Q ES,i (t), Q ES,j (t) are the reactive power of the electric spring at the i-th node and the j-th node, are the maximum reactive power of the electric spring at the i-th node and the j-th node, Q ES,i,ref is the reactive power reference value of the electric spring at the i-th node.

[0061] Specifically, when the microgrid multi-power spring consistency control system is attacked by false data injection, such as Figure 2 As shown, the consistency control law is rewritten as:

[0062]

[0063] in, Indicates the time when the false data injection attack occurs; are the reactive power of the electric springs at the i-th node and the j-th node when the false data injection attack occurs; represents the false energy constraint signal injected by the attack; γ i represents the false data injection attack control coefficient, when γ i =1, indicating that the multi-power spring consistency control system is attacked by false data injection. i =0, indicating that the multi-power spring consistency control system is not attacked by false data injection.

[0064] In this embodiment, after the consistency control law is constructed, the expected trajectory of the effective value of the bus voltage at each node of the microgrid is obtained by adjusting the effective value of the bus voltage at each node of the microgrid;

[0065] The effective value adjustment value ΔV of the bus voltage at each node of the microgrid is obtained i (t) Generate the expected trajectory V of the effective value of the bus voltage at each node of the microgrid i * , specifically:

[0066] V i * =V i des +ΔV i (t),

[0067] Among them, V i des is the rated value of bus voltage at each node of the microgrid,

[0068] In this embodiment, state variables are selected to establish a bilinear model of an AC microgrid containing multiple power springs;

[0069] Select the state variable x = [i L,d i L,q V ES,d V ES,q ] T , the bilinear model of AC microgrid with multiple power springs can be written as:

[0070]

[0071] in, is the x derivative; m d 、m q are the d-axis and q-axis components of the switching quantity of the electric spring converter, respectively. The switching quantity of the electric spring converter refers to the duty cycle of the SPWM signal of the electric spring; i L,d 、i L,q are the d-axis and q-axis components of the electric spring filter inductor current respectively; V ES,d 、V ES,q They are the d-axis and q-axis components of the power spring output voltage respectively

[0072] in,

[0073] System parameter matrix:

[0074]

[0075] The d-axis bilinear matrix of the power spring is:

[0076]

[0077] The q-axis bilinear matrix of the power spring is:

[0078]

[0079] Perturbation matrix:

[0080]

[0081] Among them, C, L f They are the power spring capacitor and filter inductor respectively; V dc,d 、V dc,q are the d-axis and q-axis components of the DC side voltage of the power spring converter respectively; i d 、i q are the d-axis and q-axis components of the microgrid line current respectively; ω is the microgrid angular frequency. a1 is the system impedance ratio;

[0082] in,

[0083]

[0084] R G , L G are the resistance and inductance of the microgrid line respectively; Z C , Z NC They are critical load impedance and non-critical load impedance respectively;

[0085] In this embodiment, the expected trajectory of the state variable is obtained by calculating the expected trajectory of the effective value of the bus voltage at each node of the microgrid; i * The expected trajectory x* of the state variable can be obtained.

[0086] In this embodiment, the expected trajectory of the state variable is combined with the state variable to obtain the output variable of the AC microgrid bilinear model containing multiple power springs;

[0087] The expression of the output variable y is:

[0088]

[0089] Among them, x* is the expected trajectory of the state variable;

[0090] Δx is the expected trajectory tracking error of the state variable:

[0091] Δx=xx * ;

[0092] x is the selected state variable:

[0093] x=[i L,d i L,q V ES,d V ES,q ] T

[0094] The d-axis bilinear matrix of the power spring is:

[0095]

[0096] The q-axis bilinear matrix of the power spring is:

[0097]

[0098] A positive definite symmetric matrix P satisfies:

[0099]

[0100] In this embodiment, a passive control law is constructed, and the output variable is brought into the constructed passive control law to obtain the output variable of the passive control law;

[0101] In order to eliminate the tracking error of the expected trajectory of the state variables, the input variables of the bilinear model of the AC microgrid with multiple power springs are defined as follows:

[0102] u=[m d m q 00] T ,

[0103] m d 、m q They are the d-axis and q-axis components of the switching quantity of the electric spring converter respectively;

[0104] The designed passive control law is:

[0105] Δu=-Ky+u *

[0106] Among them, u * is the expected trajectory of the input variable; K is the proportional coefficient of the passive controller; Δu is the output variable of the passive controller, which is used to generate the SPWM signal to control the power spring. By reasonably adjusting the power spring, the bus voltage fluctuation caused by false data attack can be suppressed to achieve stable bus voltage of the AC microgrid.

[0107] In this embodiment, the output variable of the passive control law is used to generate an SPWM signal for controlling the electric spring, and the bus voltage fluctuation caused by the false data attack is suppressed.

[0108] In this embodiment, according to the passive control theory, the designed passive control law can achieve global asymptotic stability of the microgrid multi-power spring closed-loop control system to the desired operating point under the false data injection attack, that is, it can quickly suppress the microgrid bus voltage fluctuation caused by the false data injection attack by adjusting the power spring output voltage and the filter inductor current, and maintain the stable operation of the AC microgrid multi-power spring under the false data injection attack.

[0109] In this embodiment, in order to verify the effectiveness of the invented passivity control method, the following simulation is performed:

[0110] At t = 0.5s, the electric spring is put into operation;

[0111] At t=5s, the voltage on the source side of the microgrid fluctuates, and the effective value of the voltage suddenly increases from 110V to 112V. At the same time, each power spring consistency controller is attacked by constant and bounded false data injection;

[0112] At t = 10s, the active power of the key load fluctuates, and the key load Z c,1 , Z c,2 Sudden increase from 120Ω to 160Ω;

[0113] At t=15s, the invented passive control method is started, and the simulation results are as follows: Figure 3 , Figure 4 shown.

[0114] The simulation results show that:

[0115] At t=0.5s, the power spring is put into operation, the average effective value of the bus voltage at each node is maintained at 110V, and the microgrid operates smoothly at the expected working point;

[0116] During t=5s-10s, the voltage on the source side of the microgrid and the active power of the key load fluctuated, and each power spring consistency controller was attacked by false data injection. The bus voltage and reactive power of each node deviated from the expected operating point, and the mean effective value of the bus voltage of each node deviated from 110V.

[0117] At t=15s, the designed passive control method is started, the state variables and input variables quickly track the expected trajectory, the bus voltage and reactive power of each node are stabilized at the expected operating point, and the effective value of the bus voltage of each node is maintained at 110V.

[0118] In this embodiment, it is obvious that the designed passive control method can maintain the stable operation of the AC microgrid multi-power spring under the false data injection attack, and quickly suppress the microgrid bus voltage fluctuation caused by the false data injection attack.

[0119] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for controlling the passivity of multiple power springs in an AC microgrid under false data attacks, characterized in that: The method steps include: S1. Construct a multi-power spring consistency control law under false data injection attack to obtain the effective value regulation of the bus voltage at each node of the microgrid; S2, obtaining the expected trajectory of the effective value of the bus voltage at each node of the microgrid by adjusting the effective value of the bus voltage at each node of the microgrid; S3, select state variables and construct a bilinear model of AC microgrid with multiple power springs; S4, obtaining the expected trajectory of the state variable from the expected trajectory of the effective value of the bus voltage at each node of the microgrid; S5. Combining the expected trajectory of the state variable with the state variable to obtain the output variable of the AC microgrid bilinear model containing multiple power springs; S6. construct a passive control law, and bring the output variable into the constructed passive control law to obtain the output variable of the passive control law; S7. Based on the output variable of the passive control law, an SPWM signal for controlling the working state of the electric spring is generated accordingly to suppress the bus voltage fluctuation caused by the false data attack.

2. According to the method for controlling the passivity of multiple power springs in an AC microgrid under false data attack in claim 1, it is characterized in that: The process of constructing the consistency control law of multiple power springs under the false data injection attack in S1 includes: firstly determining the consistency control law of multiple power springs; Then the multi-power spring consistency control law is determined when attacked by false data injection.

3. The method for controlling the passivity of multiple power springs in an AC microgrid under false data attack according to claim 2 is characterized in that: The multi-electric spring consistency control law is: in, is the coupling coefficient between the effective value of the voltage at the i-th node and the reactive power of the electric spring; a ij is the value of the node (i, j) in the communication network adjacency matrix; g i is the consistency control constraint coefficient; Q ES,i (t), Q ES,j (t) are the reactive power of the electric spring at the i-th node and the j-th node, are the maximum reactive power of the electric spring at the i-th node and the j-th node, Q ES,i,ref is the reactive power reference value of the electric spring at the i-th node; The multi-power spring consistency control law when attacked by false data injection is: in, Indicates the time when the false data injection attack occurs; are the reactive power of the electric springs at the i-th node and the j-th node when the false data injection attack occurs; represents the false energy constraint signal injected by the attack; γ i represents the false data injection attack control coefficient when γ i =1, indicating that the multi-power spring consistency control system is attacked by false data injection. i =0, indicating that the multi-power spring consistency control system is not attacked by false data injection.

4. According to the method for controlling the passivity of multiple power springs in an AC microgrid under false data attack of claim 1, it is characterized in that: The state variables in S3 specifically include the d-axis and q-axis components of the electric spring filter inductor current and the d-axis and q-axis components of the electric spring output voltage: x=[i L,d i L,q V ES,d V ES,q ] T Among them, x is the state variable, i L,d 、i L,q are the d-axis and q-axis components of the electric spring filter inductor current respectively; V ES,d 、V ES,q They are the d-axis and q-axis components of the power spring output voltage respectively.

5. The method for controlling the passivity of multiple power springs in an AC microgrid under false data attack according to claim 1 is characterized in that: The expected trajectory of the effective value of the bus voltage at each node of the microgrid in S4 is the superposition value of the effective value adjustment amount of the bus voltage at each node of the microgrid and the rated value of the bus voltage at each node of the microgrid: V i * =V i des +ΔV i (t), Among them, V i * is the expected trajectory of the effective value of the bus voltage at each node of the microgrid; V i des is the rated value of bus voltage at each node of the microgrid; ΔV i (t) is the effective value regulation of bus voltage at each node of the microgrid.

6. The method for controlling the passivity of multiple power springs in an AC microgrid under false data attack according to claim 1 is characterized in that: The AC microgrid bilinear model containing multiple power springs in S3 is specifically: in, is the x derivative; m d 、m q are the d-axis and q-axis components of the switching quantity of the electric spring converter respectively; A is the system parameter matrix; B1 is the d-axis bilinear matrix of the electric spring; B2 is the q-axis bilinear matrix of the electric spring; d is the disturbance matrix; C.L f They are the power spring capacitor and filter inductor respectively; V dc,d 、V dc,q are the d-axis and q-axis components of the DC side voltage of the power spring converter respectively; i d 、i q are the d-axis and q-axis components of the microgrid line current respectively; ω is the microgrid angular frequency; a1 is the system impedance ratio.

7. The method for controlling the passivity of multiple power springs in an AC microgrid under false data attack according to claim 6 is characterized in that: The expression of the output variable y of the AC microgrid bilinear model containing multiple power springs is: Where x* is the expected trajectory of the state variable; Δx is the tracking error of the expected trajectory of the state variable, Δx = xx * ; P is a positive definite symmetric matrix.

8. The method for controlling the passivity of multiple power springs in an AC microgrid under false data attack according to claim 7 is characterized in that: The positive definite symmetric matrix P satisfies:

9. The method for controlling the passivity of multiple power springs in an AC microgrid under false data attack according to claim 1 is characterized in that: When constructing the passive control law in S6, the input variable u of the bilinear model of the AC microgrid containing multiple power springs is first defined, including the d-axis and q-axis components of the switching quantity of the power spring converter: u=[m d m q 0 0] T Among them, m d 、m q They are the d-axis and q-axis components of the switching quantity of the electric spring converter respectively; The constructed passive control law is specifically: Δu=-Ky+u * Among them, Δu is the output variable of the passive control law, u* is the expected trajectory of the input variable of the passive control law; K is the proportional coefficient of the passive controller; y is the output variable of the bilinear model.

10. A method for controlling the passivity of multiple power springs in an AC microgrid under false data attack according to claim 6 or 9, characterized in that: The duty cycle of the SPWM signal generated in S7 corresponds to the switching value of the electric spring converter.

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