Research On Energy Management And Coordinated Control Strategy Of The DC Microgrid Clusters

In the background of pursuing high-quality development,the development of renewable energy has become a global consensus.Renewable energies,such as solar energy and wind energy,play an increasingly important role in the energy stage.As an important form of new energy consumption,the DC microgrids have been widely concerned,however,their small system inertias may lead to their poor anti-disturbance characteristics.The DC microgrid clusters,as an extension of the DC microgrids,can effectively make up for the poor antidisturbance of the DC microgrids.Through the energy management and coordinated control of some distributed generations in the DC microgrid clusters,the consumption of renewable energies,as well as the economic and reliable operation of the DC microgrid clusters can be realized better.Firstly,the simulation models of common distributed generations,i.e.,wind power generator and fuel cell,are established and verified based on the aerodynamic and electrochemical model respectively.The control strategy of wind power generator and photovoltaic cell are designed and verified.Consequently,the composition of the DC submicrogrids used in this thesis is established,which lays a foundation for the establishment of the DC microgrid clusters.Secondly,the typical architecture of the DC microgrid clusters and control operation mode built in this thesis are analyzed and determined,which lays a foundation for the establishment of day-ahead scheduling model and energy management of the DC microgrid clusters.The energy management and coordination control of the DC microgrid clusters include the lower-layer coordination control of each unit in the DC sub-microgrids and the upper-layer optimal scheduling of the DC microgrid clusters.In order to realize the coordinated control of the energy storages and the controllable distributed generations in the DC sub-microgrids,the control parameters of the interface converter are designed,and the traditional droop control is improved in this thesis,which achieve the accurate power distribution,the non-deviation control of the common DC bus voltage,and the adaptive adjustment of the droop coefficient.In order to realize the energy management of the DC microgrid clusters,the photovoltaic,wind power and load data used in the DC microgrid clusters built in this thesis are first obtained based on the k-means algorithm.A day-ahead scheduling model suitable for energy management of the DC microgrid clusters is then built.Based on this day-ahead scheduling model,the CPLEX native algorithm and the alternating direction multiplier method are used to manage the energy of the DC microgrid clusters respectively,and the optimal reference power applied to the coordinated control of the DC microgrid clusters is obtained.The economic operation of the DC microgrid clusters is realized through the comparison between the optimal planning operation cost and the traditional operation cost of evenly distributed power distribution,which proves the effectiveness of energy management.In order to verify the correctness of the energy management combined with coordinated control of the DC microgrid clusters,MATLAB/Simulink and RT-LAB simulations are carried out in this thesis.The simulation models of the DC microgrid clusters are first established in MATLAB/Simulink.Then,based on the energy management data,the simulation of three operation cases of the DC microgrid clusters are carried out,which verifies the feasibility of energy management combined with coordinated control and the superiority of the DC microgrid clusters.Finally,based on the RT-LAB simulation platform,further verification of the improved droop control and the simulation of two operation cases of the DC microgrid clusters are completed.