Research On Control Strategy For Smoothing Power Fluctuations In Campus Microgrid

As new energy technologies continue to evolve,the significance of renewable energy generation,such as photovoltaic and wind power,has become increasingly prominent..Microgrids,as innovative power systems integrating photovoltaic,wind,and other renewable energy sources,effectively enhance distributed energy utilization,ensure critical load power supply,and improve grid stability,thereby garnering widespread attention.With the gradual increase of its permeability in the power grid,incorporating hybrid energy storage systems into microgrids has emerged as an effective solution for absorbing renewable energy output fluctuations,ensuring stable microgrid operation.In this paper,the control strategy of campus-based microgrid is studied with the background of campus-based photovoltaic microgrid containing hybrid energy storage system.In a small-scale microgrid like those on campuses,operational objectives should primarily focus on: 1.Minimizing the energy exchange with the large power grid and reducing the impact on the large power grid while maintaining system stability.2,Maximizing the absorption of new energy output to avoid the phenomenon of light abandonment.3Smoothing new energy generation fluctuations to ensure overall microgrid system stability.Therefore,The research objectives in this paper address these goals.Firstly,the paper examines distributed micro-sources within campus microgrids,establishing a mathematical model for photovoltaic power generation units to better understand output characteristics and maximize energy utilization.Additionally,the paper analyzes hybrid energy storage unit models to study the distinct characteristics of lead batteries and supercapacitors,as well as their power absorption capacities.The model analysis of hybrid energy storage unit is carried out to study the different characteristics of lead battery and supercapacitor and their absorbing power capacity.Secondly,power distribution strategies for hybrid energy storage systems in campus microgrids,involve allocating power fluctuations within subnets according to their characteristics.High-frequency fluctuations are managed by supercapacitors,while low-frequency components are handled by lead-acid batteries.By utilizing the distinct characteristics of the two energy storage units,the microgrid system can manage fluctuations across different frequency ranges,ultimately reducing the impact of new energy output or load switching on the stable operation of campus microgrids.Finally,in campus microgrids,a segmented control strategy for interconnected converters is proposed.This strategy improves upon traditional normalized control by dividing the operating range of interconnected converters.The characteristic value is obtained by normalizing the AC/DC subnet bus voltage,which is then used to assess the operating conditions of both subnets.To address the issue of frequent operation of interconnected converters,threshold conditions are set to control their switching,ultimately achieving stable operation for both subnets.Simulations are conducted using MATLAB/Simulink.A campus microgrid model is established,encompassing new energy generation units,energy storage units,and load units.This simulation verifies the effectiveness of the subnet self-governance control strategy and the internetwork mutual aid control strategy.