Energy Management Method Based On Online Optimization For Micro-grids On The User Side

Financial incentives,peak-valley prices as well as the environmental concerns are the driving forces behind the motivation of consumers towards installing renewable energy resources and energy storage equipments in a large scale.Mirogrids on the user side focus on the comprehensive utilization of demand-side resouces.However,there is not enough attention to the need of consumers in the existent related research work.And the research on the online energy management for microgrids on the user side is still insufficient.Therefore,it is of great significance to study the online energy management methods of microgrids on the user side.In this paper,the current domestic and international research situations of energy management and interconnected operation for microgrids on the user side are first introduced,and the shortcomings of the existing research work are briefly summarized.According to the energy management demand and application characteristics of micro-grids on the user side,the theoretical basis of online optimization and its application situations are summarized.Particularly,the basic principles,application characteristics,optimal performances and application scope of Lyapunov optimization are discussed in detail.The evaluation indexes,the key features and existent difficulties of online optimizaiton algorithms are summarized.Secondly,an online energy management method is proposed for a single microgrid on the user side to reduce the electricity cost of consumers.Based on the Lyapunuov optimization theory,the controllable load queues are constructed and the initial energy management problem is transformed into a linear programming problem at each moment.Based on the non-forecasting mechanism,the real-time control of the controllable load can be realized by obtaining only the online information.Event-triggering mechanism is adopted to trigger the execution of online algorithm,so as to cut down the execution frequency and unnecessary calculation.The simulation results verify that the proposed method can effectively decrease the electricity bill of users with the guarantee of comfort level.The influence of model parameters on the optimal performance is also analyzed in the simulation.Finally,an online energy sharing method is proposed for microgrid cluster on the user side to improve the self-sufficiency of microgrids and promote the local consumption of renewable energy.Based on the Lyapunov optimization theory,the concept of virtual energy storage queues is developed.The initial ene rgy sharing problem is transformed into a linear programming problem at each moment.Only the current information is needed to make the real-time decisions of the sharing electricity among microgrids.The simulation results verify that the proposed method can effectively improve the self-consumption of renewable energy among the microgrids with the guarantee of satisfying load demand.The influence of configuration parameters in microgrids on the optimization result is also analysed in the simulation.