The Design Of Fault Tolerant Controller For Networked Control System With Denial-of-Service Based On Dynamic Event-Triggered

Networked control system is a kind of complex system combining information space and physical systems.Under the open network environment,networked control system will face more security threats from physical space and information space.With the intelligence and diversification of attack methods,attackers have realized intrusion from the information space and caused non-contact damage to the system,causing security accidents.Therefore,how to ensure the safety of physical systems from the perspective of control theory and methods has important theoretical and practical significance.As the current mainstream attack method,scholars have made great progress in modeling its behavior,its impact on the system,and response control strategies in this case.However,there are still too many restrictions in the modeling process of denialof-service attacks,such as specific probability distribution,specif ic period,etc.On the other hand,in order to save network bandwidth and increase the utilization efficiency of communication resources,scholars have propo sed the event-triggered mechanism.In order to reduce the sensitivity of event-triggered conditions to state fluctuations,a dynamic event-triggered mechanism that uses internal variables in the event-triggered conditions to equivalently filter the state has recently become a research hotspot.The networked LLC resonant converter in the smart grid has been called a new trend due to its high power density and high efficiency.Inspired by this,this paper studies the application of fault-tolerant controllers in LLC resonant converters in networked control system with denial-of-service attacks based on dynamic event-triggered.The main contributions of this paper include the following aspects:A fault detection filter is designed for networked control system with denialof-service attacks based on dynamic event-triggered.Aiming at the limitation that the Bernoulli binomial distribution cannot describe the limited ability of denialof-service attacks,a method for characterizing denial-of-service attacks with limited energy based on the semi-Markov packet loss process is proposed.Furthermore,the denial-of-service attacks packet loss is modeled as a linear system model with semi-Markov jumps,and the stability analysis of the fault detection system containing the fault detection filter and the filter par ameter design method are given.At last,simulation results are shown to verify the proposed method.Aiming at the networked control system based on the dynamic eventtriggered mechanism in the case of denial-of-service attacks,a fault-tolerant controller is designed on the basis of the fault detection filter to make the system stable after a fault,and at the same time have a certain distu rbance suppression performance.The smoothing function is introduced to reduce the jitter caused by switching between multiple controllers.The minimum trigger time interval under the dynamic event-triggered mechanism is discussed,and the proof of the existence of the lowest bound of the minimum time interval is given,which shows that the system can avoid the Zeno behavior.A simulation example verifies the effectiveness of the proposed method.For LLC resonant converters in smart grids,traditional power electronic technology control methods are combined with networked control system theory,and a fault detection filter and fault-tolerant controller based on a dynamic eventtriggered mechanism are proposed in the case of denial-of-service attacks to verify the dynamic event trigger fault-tolerant control method proposed for the networked control system with denial-of-service attack.