Safe constant power control method for micro-grid under false information injection attack

Abstract

The invention relates to the field of power grids, in particular to a safe constant-power control method for a micro-grid under false information injection attack. The method comprises the following steps: firstly, establishing a micro-grid distributed power supply model, and establishing a dynamic model for describing a distributed power supply inverter in a constant power control mode according to the power supply model; and then, analyzing false information injection attacks, modeling damage of the false information injection attacks to the micro-grid distributed power supply model, and designing an extended state observer to observe damaged information. Finally, designing a sliding mode controller and setting controller parameters; and enabling the micro-grid distributed power supply to stably track the reference power of the energy management system based on the controller. According to the invention, by providing an innovative false information injection attack protection scheme, the constant power control of the micro-grid is optimized, the safety and stability of the system are remarkably improved, and the method is of great significance to the construction, operation and maintenance of an intelligent power grid.

Description

Technical Field

[0001] The invention relates to the field of power grids, and in particular to a safe constant power control method for a microgrid under a false information injection attack. Background Art

[0002] As a new type of distributed power system, microgrid is an important component of modern energy system. Microgrid can operate independently in a local area or in parallel with the main grid, with high flexibility, controllability and energy efficiency. In the context of global energy transformation and sustainable development, microgrid has important application value in coping with the challenges faced by traditional power grids, improving the reliability of power supply, optimizing energy management, and reducing carbon emissions.

[0003] Microgrids are usually composed of multiple different types of distributed energy, loads and energy storage devices, and the operation of the system is affected by many uncertain factors. These uncertainties and disturbances may lead to reduced stability of microgrids in grid-connected or islanded modes. Although some advanced control strategies such as sliding mode control and predictive control have been applied to microgrid control, the robustness and anti-disturbance capabilities of the system still need to be improved, especially in the face of emergencies, the system may not be able to quickly recover to a stable state. With the deep integration of microgrid systems with smart grids and the Internet of Things, the importance of communication networks in microgrids is increasing. However, this also makes microgrids more vulnerable to false information injection attacks. Attackers can mislead the dispatching decisions of microgrids by tampering with sensor data or control commands, resulting in incorrect power dispatching or system failures. Although some detection methods and protection technologies for microgrids have been proposed, the existing security protection measures have some defects in real-time, accuracy and scalability, and cannot completely prevent the diverse means of false information attacks.

[0004] To this end, a safe constant power control method for microgrids under false information injection attacks is proposed. This method uses the extended state observer to observe the damaged information and the fast response and strong robustness of the sliding mode controller to ensure that the damaged situation can be accurately and quickly estimated and responded quickly when attacked by false information, thereby ensuring the stability of constant power output and improving the overall operation efficiency of the microgrid. Summary of the invention

[0005] The purpose of the present invention is to provide a safe constant power control method for a microgrid under a false information injection attack. The present invention discloses a safe constant power control method for a microgrid under a false information injection attack. First, a distributed power supply model of a microgrid is established to describe the dynamic model of a distributed power supply inverter under a constant power control mode. Subsequently, the false information injection attack is analyzed, the damage caused to the distributed power supply model of the microgrid is modeled, and an extended state observer is designed to observe the damaged information. Finally, a sliding mode controller is designed and controller parameters are set; based on the controller, the distributed power supply of the microgrid is made to stably track the reference power of the energy management system.

[0006] A safe constant power control method for a microgrid under a false information injection attack of the present invention comprises the following steps:

[0007] S1. According to the operation principle of the distributed power source of the microgrid, the differential equation and the first state space equation of the distributed power source inverter under the constant power control mode are obtained;

[0008] S2. Analyze the false information injection attack, establish a model of the damage caused by the false information to the distributed power supply of the microgrid, and obtain the second state space equation of the distributed power inverter attacked by the false information injection attack;

[0009] S3, expanding the state space equation of the distributed power inverter attacked by false information injection, constructing an expanded state space equation, designing an expanded state observer according to the expanded state space equation, observing the false information injection attack, and calculating a state estimate; calculating a state error according to the state estimate, obtaining a system error equation, and configuring the system matrix eigenvalue of the system error equation by a pole configuration method;

[0010] S4. Each distributed power source receives a reference current sent by an upper control level, and sets a sliding surface based on the reference current; a sliding mode controller is obtained based on the state space equation of the distributed power source inverter under the constant power control mode and the sliding surface; based on the sliding mode controller, the distributed power source of the microgrid is enabled to stably track the reference current of the energy management system.

[0011] Furthermore, according to the operating principle of the distributed power supply of the microgrid, the differential equation and the first state space equation of the distributed power inverter in the constant power control mode are obtained. The differential equation of the distributed power inverter in the constant power control mode is:

[0012]

[0013] Where R s and L s are the resistance and inductance of the LC filter circuit respectively; i dand i q They are the inductor currents on the d-axis and q-axis of the LC filter circuit respectively; and are the inductor current derivatives on the d-axis and q-axis of the LC filter circuit respectively; v dd and v dq are the capacitor voltage of the LC filter circuit; v d and v q are the output voltages of the inverter respectively; ω0 is the grid angular frequency measured by the PLL phase-locked loop;

[0014] The first state space equation of the distributed power inverter in the constant power control mode is:

[0015]

[0016] Among them, the state variable x=[i d ,i q ] T ; is the first-order derivative of x; input u=[v d , v q ] T ; d is the external disturbance, d = [v dd , v dq ] T , y is the system output, y=[i od ,i oq ] T ,i od and i oq are the measured output currents in the dq coordinate system respectively; A is the state transfer matrix, B1 is the input matrix, The external disturbance coefficient matrix B2=-B1, and the output matrix C is the unit matrix.

[0017] Further, the false information injection attack is analyzed, and the damage caused by the false information injection attack to the distributed power supply of the microgrid is modeled to obtain the second state space equation of the distributed power inverter attacked by the false information injection attack; the false information injection attack occurs in the feedback process of measuring the output current, and its impact is expressed as f, then the second state space equation of the distributed power inverter attacked by the false information injection attack is:

[0018]

[0019] Where I is the identity matrix, f is the false information injected by the attacker, and f = [f d , f q ] T , f d and f qThey are the d-axis and q-axis false information injected by the attacker respectively.

[0020] Further, the first state space equation of the distributed power inverter attacked by false information injection is expanded to construct an expanded state space equation, an expanded state observer is designed according to the expanded state space equation, the false information injection attack is observed, and a state estimate is calculated; based on the state estimate, a state error is calculated to obtain a system error equation, and the system matrix eigenvalue of the system error equation is adjusted by a pole placement method;

[0021] The state space equation of the distributed power inverter attacked by false information injection is expanded to construct an expanded state space equation; the expanded state f is set d and f q , let x1 = ∫ydt, x2 = x, x3 = f, x1, x2 and x3 are the state variables of the extended state space equation, then the extended state space equation is:

[0022]

[0023] in, and are the first-order derivatives of x1, x2, and x3, respectively, f=[f d , f q ] T , is the first-order derivative of f.

[0024] Furthermore, an extended state observer is designed according to the extended state space equation to observe the false information injection attack and calculate the state estimation value; the extended state observer is:

[0025]

[0026] Where k1, k2 and k3 are state observer gains, is the estimated value of x1, is the estimated value of x2, is the estimated value of x3, They are The first derivative of .

[0027] Further, according to the state estimation value, the state error is calculated to obtain a system error equation, and the system matrix eigenvalue of the system error equation is adjusted by a pole placement method;

[0028] According to the state estimation value, the state error is calculated as:

[0029]

[0030] Let e ​​= [e1, e2, e3] T ∈R 3 , then the error system equation is expressed as:

[0031]

[0032] in, is the first-order derivative of e;

[0033] The system matrix of the system error equation is transformed into The eigenvalues ​​of are uniformly configured as -w0, w0 is a positive real number, so that the state error converges to the equilibrium point, that is, e = [0, 0, 0] T , achieving error-free observation.

[0034] Furthermore, each distributed power source receives a reference current sent by an upper control, and sets a sliding surface according to the reference current; a sliding mode controller is obtained according to the state space equation of the distributed power source inverter under the constant power control mode and the sliding surface; based on the sliding mode controller, the distributed power source of the microgrid stably tracks the reference current of the energy management system;

[0035] Each distributed power source receives a reference current sent by the energy management system, and sets the sliding surface according to the reference current;

[0036] The reference current is i c =[i cd ,i cq ] T , where i cd for i d The reference current, i cq for i q The reference current, i d and i q are the inductor currents on the d-axis and q-axis of the LC filter circuit respectively. Let the tracking error be g = [g d , g q ] T , where g d =i cd -i d , g q =i cq -i q ; Set the sliding surface to:

[0037] s = g + k∫gdt;

[0038] Wherein, s is the sliding surface, k is the sliding coefficient, and k>0.

[0039] Furthermore, according to the state space equation of the distributed power inverter in the constant power control mode and the sliding surface, a sliding mode controller is designed, and the sliding mode controller is:

[0040]

[0041] Where A is the state transfer matrix, R s and L s are the resistance and inductance of the LC filter circuit respectively, B1 is the input matrix, B2 is the external disturbance coefficient matrix, and the state variable x=[i d ,i q ] T ,i d and i q are the inductor currents on the d-axis and q-axis of the LC filter circuit, d is the external disturbance, g is the tracking error, s is the sliding mode surface, and k is the sliding mode coefficient;

[0042] Design the Lyapunov function as Substituting into the sliding mode controller, we get Among them, s is the sliding surface, k is the sliding coefficient, and the sliding mode controller makes g converge to 0, thereby tracking the reference current sent by the energy management system.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] 1. By designing an extended state observer, it is possible to monitor and repair data damage caused by false information injection attacks in real time, effectively reducing the impact of malicious attacks on the stability of microgrid operation. The introduction of the observer improves the robustness of the system, allowing the microgrid to maintain reliable operation in the face of complex external interference.

[0045] 2. The present invention is based on the design of sliding mode controller, which can provide accurate control of distributed power dynamics, and ensure that distributed power can stably track the reference power of the energy management system even in the case of false information attack or other dynamic uncertainties. This control method not only enhances the dynamic response capability of the system, but also ensures the stability of constant power output and improves the overall operation efficiency of the microgrid.

[0046] 3. Through a detailed analysis of the distributed power model and the attack and destruction model, the present invention proposes a systematic, multi-constrained trajectory planning and control method. This method can optimize the operation trajectory of distributed power while satisfying multiple physical constraints of the system, thereby providing a more efficient energy scheduling solution for the microgrid and improving the overall performance of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0048] The present invention will be further described in detail below in conjunction with the specific drawings.

[0049] The present invention discloses a safe constant power control method for a microgrid under a false information injection attack. First, a distributed power supply model of a microgrid is established, and a dynamic model of a distributed power supply inverter under a constant power control mode is described. Subsequently, the false information injection attack is analyzed, the damage caused to the distributed power supply model of the microgrid is modeled, and an extended state observer is designed to observe the damaged information. Finally, a sliding mode controller is designed, and controller parameters are set; based on the controller, the distributed power supply of the microgrid is enabled to stably track the reference power of an energy management system. The present invention optimizes the constant power control of a microgrid by proposing an innovative false information injection attack protection scheme, significantly improves the safety and stability of the system, and is of great significance to the construction and operation and maintenance of smart grids.

[0050] Compared with the prior art, the present invention provides a safe constant power control method for a microgrid under a false information injection attack, which has significant technical advantages and practical value. First, by establishing a dynamic model of a distributed power source, the present invention deeply analyzes the operating characteristics under the constant power control mode and the damage mechanism of the false information injection attack, which not only clarifies the impact of the attack on the system stability, but also provides an accurate damage modeling method, which is an important supplement to the inadequate processing of complex attack scenarios in the prior art. Secondly, the designed extended state observer can observe and repair damaged information caused by false information attacks in real time, significantly improving the system's robustness to external disturbances and abnormal data, while the prior art often lacks real-time and repair capabilities when facing false data tampering. Finally, through the design of a sliding mode controller, the present invention realizes the precise control of distributed power sources, ensuring that they can stably track the reference power, thereby greatly improving the dynamic response capability and stability of the microgrid under multiple constraints.

[0051] Embodiment 1

[0052] like Figure 1 As shown, a safe constant power control method for a microgrid under a false information injection attack of the present invention comprises the following steps:

[0053] S1. According to the operation principle of distributed power supply in microgrid, the differential equation and state space equation of distributed power supply inverter in constant power control mode are obtained;

[0054] The differential equation of the distributed power inverter in the constant power control mode is:

[0055]

[0056] Where R s and L s are the resistance and inductance of the LC filter circuit respectively; i d and i q They are the inductor currents on the d-axis and q-axis of the LC filter circuit respectively; and are the inductor current derivatives on the d-axis and q-axis of the LC filter circuit respectively; v dd and v dq are the capacitor voltage of the LC filter circuit; v d and v q are the output voltages of the inverter respectively; ω0 is the grid angular frequency measured by the PLL phase-locked loop;

[0057] From the differential equation of the above inverter, the state space equation of the system can be obtained as follows:

[0058]

[0059] Among them, the state variable x=[i d ,i q ] T ∈R 2 ; is the first-order derivative of x; input u=[v d , v q ] T =; external disturbance d = [v dd , v dq ] T ∈R 2 , output y=[i od ,i oq ] T ,i od and i oq are the measured output currents in the dq coordinate system respectively; the state transfer matrix A is Input Matrix The external disturbance coefficient matrix B2=-B1, and the output matrix C is the unit matrix.

[0060] The dynamic model of the microgrid distributed power inverter is established and its state space equation is derived, which fully utilizes the component decoupling advantage of the dq coordinate system, not only accurately describes the dynamic characteristics of the inverter, but also provides a systematic and standardized tool for controller design, system optimization and disturbance resistance. This modeling method makes the microgrid system have higher accuracy, robustness and applicability.

[0061] S2. Analyze the false information injection attack, model the damage caused by it to the microgrid distributed power model, and design an extended state observer to observe the damaged information, specifically:

[0062] The false information injection attack occurs during the feedback process of measuring the output current, and its impact is expressed as f. Then the state space equation of the distributed power inverter attacked by the false information injection attack is:

[0063]

[0064] Where I is the identity matrix, f is the false information injected by the attacker, and f = [f d , f q ] T ∈R 2 , f d and f q They are the d-axis and q-axis false information injected by the attacker respectively.

[0065] By directly modeling the false information injection attack as a disturbance in the system, the impact path of the attack on the measurement data is clarified, and the recognition ability and defense efficiency of the false information injection attack are improved. Compared with the traditional model, this method can better cope with the challenges of network attacks, enhance the robustness, real-time and security of the microgrid system, and provide a solid guarantee for the stable operation of the system in harsh environments.

[0066] S3. Expand the state space equation of the distributed power inverter attacked by false information injection, construct an expanded state space equation, design an expanded state observer according to the expanded state space equation, observe the false information injection attack, and calculate the state estimation value; calculate the state error according to the state estimation value, obtain the system error equation, and adjust the system matrix eigenvalue of the system error equation by the pole configuration method;

[0067] Specifically, the state space equation of the distributed power inverter attacked by false information injection is expanded to construct an expanded state space equation; the expanded state f is set d and f q , let x1 = ∫ydt, x2 = x, x3 = f, x1, x2, x3 are the state variables of the extended state space equation, then the extended state space equation is:

[0068]

[0069] in, and are the first-order derivatives of x1, x2, and x3 respectively; is the first-order derivative of f.

[0070] By establishing an extended state system under false information injection attacks, the system can more accurately identify and compensate for the disturbances caused by the attack, enhancing the robustness, real-time and security of the microgrid. Compared with traditional control strategies, this method provides a more effective attack detection, repair and real-time response mechanism when facing false information injection attacks, ensuring the stable and reliable operation of the system. At the same time, the extended state method simplifies the controller design and can adapt to a variety of complex attack scenarios, with strong practicality and scalability.

[0071] An extended state observer is designed according to the extended state space equation to observe the false information injection attack and calculate the state estimation value; the extended state observer is:

[0072]

[0073] Where k1, k2 and k3 are state observer gains, is the estimated value of x1, is the estimated value of x2, is the estimated value of x3, They are The first derivative of .

[0074] The design of an extended state observer significantly improves the robustness, stability and adaptability of the microgrid system against false information injection attacks and other disturbances.

[0075] Calculate the state error according to the state estimation value to obtain the system error equation, and adjust the system matrix eigenvalue of the system error equation by pole placement method;

[0076] According to the state estimation value, the state error is calculated as:

[0077]

[0078] Let e ​​= [e1, e2, e3] T ∈R 3 , then the error system equation is expressed as:

[0079]

[0080] in, is the first-order derivative of e;

[0081] Therefore, the system matrix of the system error equation is transformed into The eigenvalues ​​of are uniformly configured as -w0, where w0 is a positive real number, so that the state error converges to the equilibrium point, that is, e = [0, 0, 0] T , achieving error-free observation.

[0082] By modeling the observation error as the error system state equation and using the pole placement method to uniformly configure the eigenvalues ​​of the system matrix as stable negative real numbers, the error system can be quickly converged. This can gradually reduce the observation error to zero and achieve error-free observation of the system state.

[0083] S4. Each distributed power source receives a reference current sent by the upper control, and sets a sliding surface according to the reference current; obtains a sliding mode controller according to the state space equation of the distributed power source inverter under the constant power control mode and the sliding surface; based on the sliding mode controller, the microgrid distributed power source is made to stably track the reference current of the energy management system, specifically:

[0084] Each distributed power source receives a reference current sent by the energy management system, and sets the sliding surface according to the reference current;

[0085] The reference current is i c =[i cd ,i cq ] T =, where i cd for i d The reference current, i cq for i q The reference current, let the tracking error be g = [g d , g q ] T =, where g d =i cd -i d , g q =i cq -i q ; Set the sliding surface to:

[0086] s = g + k∫gdt;

[0087] Wherein, s is the sliding surface, k is the sliding coefficient, and k>0.

[0088] By introducing the error integral term in the sliding surface, the steady-state performance and anti-interference ability of the system are significantly improved. Error integration can accumulate tracking errors, eliminate the steady-state deviation of the system, and ensure that the distributed power supply can accurately track the reference current while avoiding deviations caused by external disturbances or system uncertainties.

[0089] According to the state space equation of the distributed power inverter in the constant power control mode and the sliding surface, a sliding mode controller is designed. The sliding mode controller is:

[0090]

[0091] Where A is the state transfer matrix, Rs and Ls are the resistance and inductance of the LC filter circuit respectively, B1 is the input matrix, B2 is the external disturbance coefficient matrix, and the state variable x=[i d ,i q ] T ,i d and i q are the inductor currents on the d-axis and q-axis of the LC filter circuit, d is the external disturbance, g is the tracking error, s is the sliding mode surface, and k is the sliding mode coefficient;

[0092] Design the Lyapunov function as Substituting into the sliding mode controller, we get Among them, s is the sliding surface, k is the sliding coefficient, and the sliding mode controller makes g converge to 0, thereby tracking the reference current sent by the energy management system.

[0093] By designing a suitable controller and Lyapunov function, the stability of the system and the asymptotic convergence of the error are ensured. The design of the controller enables the sliding mode controller to dynamically adjust the input to eliminate the error, while the construction of the Lyapunov function provides a mathematical stability guarantee to ensure the global convergence of the error tracking process. Ultimately, the system can accurately track the reference voltage sent by the superior and achieve efficient tracking of the dynamic reference signal.

[0094] Embodiment 2

[0095] In addition to resisting false information injection attacks, this method can also achieve flexible control under interference signals generated by the system itself.

[0096] like Figure 1 As shown, a safe constant power control method for a microgrid under a false information injection attack of the present invention comprises the following steps:

[0097] S1. According to the operation principle of distributed power supply in microgrid, the differential equation and state space equation of distributed power supply inverter in constant power control mode are obtained;

[0098] According to the operating principle of the distributed power supply in the microgrid, the differential equation of the distributed power supply inverter in the constant power control mode is:

[0099]

[0100] Where R s =1.55Ω and L s =4×10 -3 are the resistance and inductance of the LC filter circuit respectively; i d and i q They are the inductor currents on the d-axis and q-axis of the LC filter circuit respectively; and are the inductor current derivatives on the d-axis and q-axis of the LC filter circuit respectively; v dd and v dq are the capacitor voltage of the LC filter circuit; v d and v q are the output voltages of the inverter respectively; ω0=100π is the grid angular frequency measured by the PLL phase-locked loop;

[0101] The state space equation of the distributed power inverter in the constant power control mode is:

[0102]

[0103] Among them, the state variable x=[i d ,i q ] T ∈R 2 ; is the first-order derivative of x; input External disturbance d = [v dd , v dq ] T , output y=[i od ,i oq ] T ,i od and i oq are the measured output currents in the dq coordinate system respectively; the state transfer matrix A is Input Matrix External perturbation coefficient matrix The output matrix C is the identity matrix.

[0104] S2. Analyze the system interference signal, model the damage caused by it to the distributed power supply of the microgrid, and obtain the state space equation of the distributed power supply inverter attacked by false information injection, specifically:

[0105] The false information injection attack occurs during the feedback process of measuring the output current, and its impact is expressed as f. Then the state space equation of the distributed power inverter attacked by the false information injection attack is:

[0106]

[0107] Where I is the identity matrix, f is the false information injected by the attacker, and f = [f d , f q ] T ∈R 2 , p d and p q are the system disturbances on the d-axis and q-axis respectively.

[0108] S3. Expand the state space equation of the distributed power inverter under the interference signal generated by the system itself, construct an extended state space equation, design an extended state observer according to the extended state space equation, observe the interference signal, and calculate the state estimation value; calculate the state error according to the state estimation value, obtain the system error equation, and adjust the system matrix eigenvalue of the system error equation by the pole configuration method;

[0109] The state space equation of the distributed power inverter attacked by false information injection is expanded to construct an expanded state space equation; the expanded state f is set d and f q , let x1 = ∫ydt, x2 = x, x3 = f, x1, x2 and x3 are the state variables of the extended state space equation, then the extended state space equation is as follows:

[0110]

[0111] in, and are the first-order derivatives of x1, x2, and x3, respectively, is the first-order derivative of f.

[0112] An extended state observer is designed according to the extended state space equation to observe the false information injection attack and calculate the state estimation value; the extended state observer is:

[0113]

[0114] Where k1, k2 and k3 are state observer gains, is the estimated value of x1, is the estimated value of x2, is the estimated value of x3, and They are and The first derivative of .

[0115] Calculate the state error according to the state estimation value to obtain the system error equation, and adjust the system matrix eigenvalue of the system error equation by pole placement method;

[0116] According to the state estimation value, the state error is calculated as:

[0117]

[0118] Let e ​​= [e1, e2, e3] T ∈R 3 , then the error system equation is expressed as:

[0119]

[0120] in, is the first-order derivative of e;

[0121] The system matrix of the system error equation is transformed into The eigenvalues ​​of are uniformly configured as [-387, -387, -0.5, -0.5, -0.5, -0.5].

[0122] The solution is k1 = [0.4360.564], k2 = [323.847318.570], k3 = [5.6843.077], so that the state error converges to the equilibrium point, that is, e = [0, 0, 0] T , achieving error-free observation.

[0123] S4. Each distributed power source receives a reference current sent by the upper control, and sets a sliding surface according to the reference current; obtains a sliding mode controller according to the state space equation of the distributed power source inverter under the constant power control mode and the sliding surface; based on the sliding mode controller, the microgrid distributed power source is made to stably track the reference current of the energy management system, specifically:

[0124] Each distributed power source receives a reference current sent by the energy management system, and sets the sliding surface according to the reference current;

[0125] The reference current is i c =[i cd ,i cq ] T ∈R 2 , where i cd for i d The reference current, i cq for i q The reference current, let the tracking error be g = [g d , g q ] T ∈R 2 , where g d =i cd -i d , g q =i cq -i q ; Set the sliding surface to:

[0126] s = g + k∫gdt;

[0127] Wherein, s is the sliding surface, k is the sliding coefficient, and k>0, k=100.

[0128] According to the state space equation of the distributed power inverter under the constant power control mode and the sliding mode surface, the sliding mode controller is obtained as follows: Design the Lyapunov function as

[0129] Taking the derivative of the Lyapunov function, we get:

[0130]

[0131] Where A is the state transfer matrix, B1 is the input matrix, B2 is the external disturbance coefficient matrix, and the state variable x=[i d ,i q ] T ,i d and i q are the inductor currents on the d-axis and q-axis of the LC filter circuit respectively, d is the external disturbance, g is the tracking error, s is the sliding surface, k is the sliding coefficient, s is the sliding surface, k is the sliding coefficient;

[0132] Also because If it is always established, the sliding mode controller makes g converge to 0, that is, it realizes the tracking of the reference current issued by the energy management system.

Claims

1. A method for controlling the safe constant power of a microgrid under a false information injection attack, characterized in that: The following steps are involved: S1. According to the operation principle of the distributed power source of the microgrid, the differential equation and the first state space equation of the distributed power source inverter under the constant power control mode are obtained; S2. Analyze the false information injection attack, establish a model of the damage caused by the false information to the distributed power supply of the microgrid, and obtain the second state space equation of the distributed power inverter attacked by the false information injection attack; S3, expanding the first state space equation of the distributed power inverter attacked by false information injection, constructing an expanded state space equation, designing an expanded state observer according to the expanded state space equation, observing the false information injection attack, and calculating a state estimation value; Calculate the state error according to the state estimation value to obtain the system error equation, and configure the system matrix eigenvalue of the system error equation by the pole configuration method; S4, each distributed power source receives a reference current sent by the upper control, and sets a sliding surface according to the reference current; A sliding mode controller is obtained according to the state space equation of the distributed power inverter and the sliding mode surface in the constant power control mode; based on the sliding mode controller, the microgrid distributed power source is enabled to stably track the reference current of the energy management system.

2. According to a method for controlling the safe constant power of a microgrid under a false information injection attack according to claim 1, it is characterized in that: The differential equation of the distributed power inverter in the constant power control mode is: Where R s and L s are the resistance and inductance of the LC filter circuit respectively; i d and i q They are the inductor currents on the d-axis and q-axis of the LC filter circuit respectively; and are the inductor current derivatives on the d-axis and q-axis of the LC filter circuit respectively; v dd and v dq are the capacitor voltage of the LC filter circuit; v d and v q are the output voltages of the inverter respectively; ω0 is the grid angular frequency measured by the PLL phase-locked loop; The first state space equation of the distributed power inverter in the constant power control mode is: Among them, the state variable x=[i d ,i q ] T ; is the first-order derivative of x; input u=[v d ,v q ] T ; d is the external disturbance, d = [v dd ,v dq ] T , y is the system output, y=[i od ,i oq ] T ,i od and i oq are the measured output currents in the dq coordinate system respectively; A is the state transfer matrix, B1 is the input matrix, The external disturbance coefficient matrix B2=-B1, and the output matrix C is the unit matrix.

3. The method for controlling the safe constant power of a microgrid under a false information injection attack according to claim 1 is characterized in that: The false information injection attack is analyzed, and the damage caused by the attack to the distributed power supply of the microgrid is modeled to obtain the second state space equation of the distributed power inverter attacked by the false information injection attack; the false information injection attack occurs in the feedback process of measuring the output current, and its influence is expressed as f, then the second state space equation of the distributed power inverter attacked by the false information injection attack is: Where I is the identity matrix, f is the false information injected by the attacker, and f = [f d ,f q ] T , f d and f q They are the d-axis and q-axis false information injected by the attacker respectively.

4. The method for controlling the safe constant power of a microgrid under a false information injection attack according to claim 3 is characterized in that: The first state space equation of the distributed power inverter attacked by false information injection is expanded to construct an expanded state space equation; the expanded state f is set d and f q , let x1 = ∫ydt, x2 = x, x3 = f, x1, x2 and x3 are the state variables of the extended state space equation, then the extended state space equation is: in, and are the first-order derivatives of x1, x2, and x3, respectively, f=[f d ,f q ] T , is the first-order derivative of f.

5. The method for controlling the safe constant power of a microgrid under a false information injection attack according to claim 4 is characterized in that: An extended state observer is designed according to the extended state space equation to observe the false information injection attack and calculate the state estimation value; the extended state observer is: Where k1, k2 and k3 are state observer gains, is the estimated value of x1, is the estimated value of x2, is the estimated value of x3, and They are and The first derivative of .

6. A method for controlling a microgrid's safe constant power under a false information injection attack according to claim 5, characterized in that: Calculate the state error according to the state estimation value to obtain the system error equation, and adjust the system matrix eigenvalue of the system error equation by pole placement method; According to the state estimation value, the state error is calculated as: Wherein, e1, e2 and e3 are the state errors of x1, x2 and x3 respectively, let e = [e1, e2, e3] T ∈R 3 , then the error system equation is expressed as: in, is the first-order derivative of e; The system matrix of the system error equation is transformed into The eigenvalues ​​of are uniformly configured as -w0, w0 is a positive real number, so that the state error converges to the equilibrium point, that is, e = [0,0,0] T , achieving error-free observation.

7. The method for controlling the safe constant power of a microgrid under a false information injection attack according to claim 1 is characterized in that: Each distributed power source receives a reference current sent by the energy management system, and sets the sliding surface according to the reference current; The reference current is i c =[i cd ,i cq ] T , where i cd for i d The reference current, i cq for i q The reference current, i d and i q are the inductor currents on the d-axis and q-axis of the LC filter circuit respectively. Let the tracking error be g = [g d ,g q ] T , where g d =i cd -i d , g q =i cq -i q ; Set the sliding surface to: s = g + k∫gdt; Wherein, s is the sliding surface, k is the sliding coefficient, and k>0.

8. The method for controlling the safe constant power of a microgrid under a false information injection attack according to claim 7 is characterized in that: According to the state space equation of the distributed power inverter in the constant power control mode and the sliding surface, a sliding mode controller is designed. The sliding mode controller is: Where A is the state transfer matrix, R s and L s are the resistance and inductance of the LC filter circuit respectively, B1 is the input matrix, B2 is the external disturbance coefficient matrix, and the state variable x=[i d ,i q ] T ,i d and i q are the inductor currents on the d-axis and q-axis of the LC filter circuit, d is the external disturbance, g is the tracking error, s is the sliding mode surface, and k is the sliding mode coefficient; Design the Lyapunov function as Substituting into the sliding mode controller, we get Among them, s is the sliding surface, k is the sliding coefficient, and the sliding mode controller makes g converge to 0, thereby tracking the reference current sent by the energy management system.

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