Research On Energy Flow Control Strategy Of Microgrid With Multi-energy Vector

The depletion of traditional energy sources and the increasing environmental pollution have led to the rapid development of multi-energy micro-grid based on clean energy.As a new power supply mode,the multi-energy micro-grid has the advantages of diversified micro-source combination,high utilization rate of renewable energy,flexible operation mode and high reliability of power supply.In this paper,a multienergy micro-grid system based on wind energy,hydrogen production from electrolytic water,methanol from coal,hydrogen-oxygen fuel cells and batteries is proposed,the optimization of micro-energy capacity allocation and the control of energy flow(electric energy flow and gas flow)allocation in multi-energy micro-grid are studied.The specific work is as follows:Firstly,the characteristics of each micro-source in the multi-energy micro-grid are analyzed and the mathematical model of each micro-source is established.Secondly,in view of the instability of wind power output,in order to better study the influence of wind power output on energy flow distribution control,the RBF neural network based on wavelet transform is used to predict the power output of wind power.In order to ensure that the wind power grid-connected power does not affect the power quality,the improved V/f droop control is used to control the wind grid-connected frequency.Then,considering the economics of multi-energy microgrid and the reliability of power supply,aiming at the optimal allocation of micro-source capacity in multi-energy micro-grid,the lowest annual cost of the multi-energy micro-grid is used as the optimization objective function,and chaotic particle swarm optimization algorithm is adopted.The optimal allocation of micro-sources in the multi-energy micro-grid and the lowest annual cost of the multi-energy micro-grid under the configuration are obtained.Finally,the concept of equivalent state of charge(ESOC)is introduced to represent the state of hydrogen storage.The hierarchical coordinated control architecture of multi-energy micro-grid system is constructed,the power flow distribution control strategy and gas flow distribution control strategy are proposed.The simulation model is built by matlab/Simulink,and the results show the effectiveness of the proposed control strategy.