Optimal Scheduling Research Of Building Integrated Photovoltaic Microgrid Considering Virtual Energy Storage

With the worsening of global energy crisis and environmental pollution,the exploitation of photovoltaic power is attracting attention from all over the world.Combining photovoltaic power with building surfaces to form building integration photovoltaic(BIPV)can make full use of solar energy and reduce building energy consumption.However,the fluctuating and random of photovoltaic power makes it difficult to efficiently use,reducing the economics of BIPV.The above problems can be effectively solved by configuring a microgrid system with energy storage equipment inside the BIPV and optimal scheduling of the microgrid.But energy storage devices are generally expensive and have a short cycle life.Therefore,this thesis introduces virtual energy storage(VES)and incorporates it into the optimal scheduling of BIPV microgrid to improve its economy.At the same time,considering the microgrid tie-line power fluctuation caused by the error of the day-ahead forecast information,the model predictive control(MPC)is used to schedule the system in real time to smooth the power fluctuation of the tie-line during the day.The main work are as follows:(1)The model of each unit in the BIPV microgrid and the VES models are established.Firstly,the basic structure of the BIPV microgrid is introduced.Secondly,the photovoltaic effect of semiconductors is used to model photovoltaic power generation,meanwhile the effects of light intensity and temperature on its output power are analyzed.The energy storage unit is lithium battery and its charging/discharging model is established according to the charging/discharging characteristics of lithium battery.The relationship between energy consumption and cooling/heating of air conditioners and water heaters is given.Finally,the VES models of the building-air conditioning system and the water heater are established based on their cooling and heat storage characteristics respectively.(2)An optimal scheduling strategy of BIPV microgrid considering VES is proposed.By identifying the decision variables,constraints and objective functions in the system operation,a linear programming-based system day-ahead optimal scheduling model is established.Based on the day-ahead forecast information,the VES power of controllable loads and lithium batteries power in the system are regulated to minimize daily operating cost of the system,and realizing the utility of lithium batteries by VES.The simulation results verify the effectiveness of the proposed strategy.(3)A real-time optimal scheduling strategy of the system based on MPC is proposed.To smooth the tie-line power fluctuations caused by errors in day-ahead forecast information,the MPC is used to schedule the system in real time during the day.Based on the results of the day-ahead optimal scheduling,the system real-time optimal scheduling model is established to minimizing the power fluctuation of the tieline.With the basis of the real-time updated forecasting information,the VES and lithium battery’s charging/discharging power are scheduled in a rolling optimization,so that the power of the tie-line follows the planned value before the day,and the charging/discharging power fluctuation of the lithium battery is minimized to prolong its life.The simulation results verify the effectiveness of the scheduling strategy.