Hierarchical Control Of Microgrid Based On Fuzzy Predictive Control VSG And Event-triggered Communication

In this paper,the hierarchical control model of microgrid is built to ensure the stability of microgrid.The limitation of traditional droop control is obtained,and the error is compensated in the secondary control.The inherent conflict between voltage control and reactive power distribution is analyzed to avoid the misunderstanding of control purpose selection.When the load changes,if the moment of inertia and damping coefficient of VSG(Virtual Synchronous Generator,VSG)remain unchanged,the suppression ability of frequency fluctuation will be very limited.Therefore,a virtual synchronous generator control scheme based on fuzzy control and model predictive control is proposed for frequency regulation of microgrid.The moment of inertia and damping coefficient of VSG are adjusted online by fuzzy controller to make full use of the regulation ability of swing equation.The maximum power control method is used to match the optimal rated power of VSG.The proposed joint control can effectively improve the dynamic response of the system.The simulation results show that the proposed control scheme can significantly improve the stability of microgrid system.The secondary control of islanded microgrid based on periodic communication generally has the problem of heavy communication burden.Therefore,a control strategy based on event triggered communication is proposed.Each DG is regarded as an agent,and then the whole communication network of microgrid is modeled as an undirected graph with virtual leader.On this basis,Lyapunov method is used to deduce the trigger condition function of frequency and voltage control in detail,and the stability analysis is carried out,so that the information transmission between adjacent DGS is needed only when the error meets the trigger condition,avoiding many unnecessary communication.In the controller of compensating frequency and voltage deviation,the predicted value of state is used to replace the actual value,which reduces the number of controller updates.Finally,combined with the simulation results,the operation process of FETC(function of event-triggered condition,FETC)is explained in detail to verify its effectiveness in reducing the number of communication in the system.