Multi-level Distributed Optimized Power Sharing Of Islanded Microgrid Based On Dynamic Droop Control

With the exhaustion of traditional energy resources,the application of renewable energy resources(RES)in the power system is increasing rapidly.The generators based on RES are usually DC generators,which is incapable to connected to the main grid,where the concepet of distributed generator(DG)and microgrid comes forth.This paper aims at the microgrid with DG based on RES,and an adaptive,multilevel optimal power sharing control strategy is proposed.Detailed research is as follows:(1)Based on the traditional droop control strategy,the coupling relationship of output power and inner variables,which is active power versus frequency(P-f),and passitive power versus voltage magnitude(Q-v).The inner dyamincs is analysed based on the droop theory,and both big signal model and small signal model are built.At last,the droop method is verified by the MATLAB/Simulink platform.(2)Considering the microgrid with high propotion of RES,where the generation of RES is fluctuant and uncertain,an adaptive fuzzy droop control(AFDC)method is proposed.In AFDC,the real-time generation and real-time energy efficiency is measured by the fuzzy controller,and the the P-f droop coefficient is optimized.The AFDC is verified by the simulation of microgrid with PV system and wind generators.(3)In view of the disadvantage of droop method,such as the deviation of voltage,the secondary control level is built to restore the voltage amplitude and to realize its consistency.The feedback linearation is used to the Q-v droop model,and the multi-angent system(MAS)is then applied to achieve the synchronization of voltage amplitude,and then to relialize the fair distribution of reactive power among the microgird.The seconday control based on feedback linearation and MAS is verified by comparison simulations of traditional droop controller and secondary controller.(4)Aiming at the actuator fault in droop controllers,a distributed fault-tolerate in droop control(FTDC)method is proposed.The two regular fault kinds,partial failure and information error,are modeled,and the fault-tolerate controller is designed to eliminate the damage.The stability analysis of FTDC is provided in order to prove its validity,and the FTDC is verified in simulations of comparison simulations of FTDC controller and MAS secondary controller.