Busbar Voltage Control And Energy Management Of Independent DC Microgrid Based On Hybrid Energy Storage

As an important part of constructing a new power system,microgrid technology undertakes the important task of bridging energy supply and demand and realizing efficient interaction between source,load and storage.Therefore,it is of certain practical significance to study how to stabilize the unbalanced power in the microgrid system,stabilize the busbar voltage,improve the utilization rate of renewable energy,reduce the uncertain risk of source load and optimize the operating cost of the system.In view of this,this paper takes the independent DC microgrid as the research object,and from the two aspects of bus voltage control and energy optimization scheduling of the microgrid,the specific work done is as follows:(1)In the independent DC microgrid,a hybrid energy storage system containing supercapacitors is constructed to improve the system stability.Meanwhile,a closed-loop control strategy based on active disturbance rejection control is designed for the performance of the hybrid energy storage system.The extended state observer is used to estimate and compensate the unknown disturbance in the system.Fuzzy adaptive and extended state observer are introduced to improve the performance of active disturbance rejection controller.Finally,through theoretical and simulation analysis,the good working performance of the designed fuzzy active disturbance rejection controller is verified,which effectively reduces the busbar voltage recovery time and enhances the hybrid energy storage system’s ability to suppress the power fluctuation of DC microgrid.The designed control strategy has strong disturbance resistance to the dynamic interference of the system and improves the stability of the system.(2)A day-ahead optimal scheduling model for independent DC microgrid is proposed based on IGDT and considering the uncertainties of wind,light and load parameters.Based on the characteristics of hybrid energy storage and flexible load,a deterministic scheduling model with "generalized energy storage" is constructed,which effectively improves the consumption level of renewable energy.At the same time,under the incentive of TOU,flexible load is added to smooth the load curve and reduce the peak-valley difference.Considering the uncertainty of wind,light and load parameters of the system,IGDT model was introduced to establish a robust model under risk avoidance strategy and an opportunity model under risk speculation strategy on the basis of the deterministic model,and to pursue the maximization of risk reduction and return from two decision-making perspectives.Through the simulation analysis of the example,the scheduling strategy quantifies the influence of uncertain factors on the system scheduling decision on the basis of reducing the operation cost of microgrid,and provides decision reference for decision-makers facing different scenarios.Moreover,the impact of different schemes and related parameters on the proposed strategy is analyzed in detail,and the feasibility of the model is verified.