Design Of Island AC Microgrid Security Controller Under Network Attacks

The microgrid has the advantages of fully utilizing renewable energy and giving full play to the benefits of distributed generation,and can switch operation in two different modes,namely island mode and grid connected mode.In the island mode,the microgrid must be independent of the large grid to keep the voltage and frequency within a relatively stable range.However,because the communication link connecting the microgrid and the distributed generation is highly open,the microgrid is vulnerable to malicious network attacks and communication delays by hackers.The microgrid has high requirements on the security and real-time of the system.If attacked,the system performance will be seriously affected,and the power safety of users of the microgrid will be affected.Therefore,in this paper,the micro grid system is analyzed and studied in combination with the theoretical method of switching system and linear matrix inequality technology in order to achieve the stability control goal of the microgrid.This paper is mainly divided into the following parts:In Chapter 2,the controller design problem under denial of service(Do S)attack is studied.This paper proposes a new time-constrained Do S attack model which is different from the previous model that needs to limit the attack frequency and duration.Based on this,a method based on switching system is designed,and an island AC microgrid model under Do S attack is established.Then the Lyapunov function is used to derive the stability criterion of the asymptotic stability of the system,and the safety controller is designed.The effectiveness of the proposed controller design method is verified through simulation.In Chapter 3,based on the study of Do S attacks,the design problem of the security controller of an islanded AC microgrid under controlled input time delay is considered.First,the model of an islanded AC microgrid under Do S attacks and controlled input time delay is established.Then,the design criteria for the controller of an islanded AC microgrid under controlled input time delay and Do S attacks are established,and the effectiveness of the proposed controller design method is verified through simulation.In Chapter 4,based on the consideration of Do S attacks,the actuator and sensor false data injection(FDI)attacks are further considered and introduced into the islanded AC microgrid.The controller design problem of the islanded AC microgrid under mixed attacks of Do S and FDI is studied.First,the model of the islanded AC microgrid under mixed attacks is established.Then,an observer is established to observe the FDI attack,and the control criteria for the islanded AC microgrid under mixed attacks are established.Finally,the effectiveness of the proposed controller design method is verified through simulation examples.