Design And Analysis Of Layered Control Of Microgrid Based On Distributed Generation

In recent years,faced with the shortage of energy resources and the worsening of the environment,people pay more and more attention to environmental protection,turning their attention to new energy,focusing on the research of new clean energy and renewable energy,improving the permeability of distributed power supply in the power system.Compared with traditional large power grid,centralized long-distance power transmission has the disadvantage of low reliability and high cost.The access to the Distributed Generator satisfies the characteristics of ‘plug and play'.When the microgrid is in operation,there are two modes,namely,connecting the main grid and running it together,and the output voltage and frequency are controlled by the main grid.Once the main grid fails,the microgrid needs to exit the main grid and enter the island mode to directly supply power to the load.At this time,the hierarchical control of the micro grid is required.This paper proposes a distributed secondary voltage control strategy for microgrids.We consider the topology of the DGS to be a non-uniform time-varying delay fixed directed graph.Then,through the input-output feedback linearization,the nonlinear dynamics of DGs is transformed into a second-order linear continuous system.In order to ensure that the output voltage amplitude of each power supply converges to the reference voltage value,a distributed controller is proposed.The stability of the closed-loop system is analyzed by the Lyapunov-Razumikhin function method.Finally,the effectiveness of the designed controller is verified by MATLAB simulation.An event-triggered secondary frequency control strategy is designed to compensate for the loss of frequency.Based on droop control,we transformed the control model into a first-order continuous model,designed two trigger functions to control two variables respectively,and finally realized the frequency compensation.According to proportional consistency control,the system is transformed into a first-order discrete system,and a distributed algorithm based on event-triggered is proposed to coordinate the operation of wind farm and flywheel energy storage matrix system(FESMS).In addition,the self-triggered mode is also studied.The algorithm achieves proportional consistency in balanced directed graph topology.Simulation results show that the algorithm is effective.Finally,the paper summarizes the whole paper and puts forward some problems to be studied.