Research On Distributed Cooperative Control Of DC Microgrid Considering State Constraints And Network Attacks

In recent years,with the development of society,environmental and energy issues have become increasingly prominent.Due to the large-scale production and use of traditional energy sources such as coal,oil,and natural gas,which have caused serious environmental pollution,countries have turned to the development of new and environmentally friendly renewable energy sources to address the resource shortage and environmental pollution issues faced in development.However,new energy power generation such as solar and wind power has the characteristics of geographical dispersion and small capacity,which poses challenges to existing power supply methods and requires more flexible power grids for transformation and transmission.Therefore,microgrids have emerged as the times require.In micro grid systems,micro source systems such as photovoltaic power generation,fuel cells,and energy storage units have DC characteristics,and distributed control of DC micro grid has characteristics such as simple structure,superior performance,and strong robustness.Therefore,distributed control of DC micro grid has a broad development prospect.However,due to the existence of a communication layer in distributed control and the lack of a central controller to monitor the operation of power generation units,it is vulnerable to network attacks that affect control accuracy and stability.Based on the DC microgrid model,this paper proposes a DC microgrid collaborative control scheme that considers state constraints and resists spurious data injection attacks.The specific research content is as follows:Firstly,a bus voltage control scheme considering state constraints is proposed to address the issue of voltage control bias in traditional droop control in DC microgrids.A parabolic droop control is used instead of traditional linear droop control to reduce voltage drop.A voltage controller based on obstacle Lyapunov function is designed to achieve bus voltage control and accurate power allocation.In the voltage controller,the backstepping method is used to deal with nonlinear problems,and the RBF neural network is used to estimate the uncertainty in the system,improving the anti-interference ability of the system.Finally,the simulation verified that the adopted control method can maintain stability in the DC microgrid system.Secondly,in distributed secondary control of DC microgrids,open network environments are vulnerable to external spurious data injection attacks that affect bus voltage stability.This paper proposes a fixed time distributed secondary control scheme based on higher order differentiators.A high order differentiator is designed to observe the attack signal,and a fixed time distributed secondary controller is further designed using the observed values to achieve compensation and suppression of the attack signal,and to achieve bus voltage adjustment and accurate power distribution.Theoretically,it is proved that the proposed controller can make the system asymptotically stable.The simulation verifies the effectiveness of the control method used.Finally,in order to solve the problem of communication redundancy in the distributed secondary control of continuous triggering in DC microgrid systems,which brings a large communication burden to the system,this paper proposes a fixed time distributed secondary control scheme based on event triggering.Based on the above distributed fixed time secondary control method,an event trigger mechanism is introduced to reduce the communication frequency between micro sources without reducing system stability,which can ensure stable system operation and reduce energy consumption.Finally,it is theoretically proven that the proposed method does not have Zeno behavior,and simulation verifies the effectiveness of the proposed scheme.