Research On Optimal Control Method For The Energy Management Of Hybrid AC/DC Microgrid

As one of the important components of the Strong Smart Grid and the most effective ways to use renewable energy,the microgrid has attracted extensive attention and research.Optimal control method for the energy management of hybrid AC/DC microgrid was studied in this paper.The energy management strategy in the parallel operation mode of microgrid based on fuzzy control was formulated to realize the its intelligent control.This paper mainly completed the following work:(1)The hybrid AC/DC microgrid with circuit switching mechanism and its energy management system were studied.The system possesses the advantages of DC microgrid and AC microgrid.A equalization control of energy storage system is implemented in the DC microgrid,switch array used for load management control is arranged in AC microgrid.Therefore,the system studied in this paper works in the parallel operation mode,which makes the energy management system more flexible.(2)The topology of the hybrid AC/DC microgrid system,the operation mode and the system functions were expounded in detail.Each mathematical model and its corresponding control strategy were established,including photovoltaic power,battery,super-capacitor,bidirectional DC/AC converter,switch array and so on.This paper emphatically studied the equalization control strategy of hybrid energy storage system,and built the simulation module of the system for analysis.(3)The energy management strategy based on fuzzy control was proposed for the parallel operation mode.The design of the fuzzy controller aiming at the stable operation of the system and the optimization of the power and loads was described in detail.It makes that the loads can connect flexibly using by switch array and that the converter and hybrid energy storage can control coordinately.The corresponding simulation model was established and demonstrated on the Matlab/Simulink platform.The research results show that the energy management strategy of the parallel mode has enabled such effects to be achieved: maintenance of power balance in case of change of PV output,assurance of voltage stability of the AC and DC power lines,improvement of utilization rate of PV power and the lifespan of energy storage system,as well as optimization of matching between the supply side and the demand side.