Study On Dc Micro-grid Containing Photovoltaic And Energy Storage Based On Model Predictive Control And Consensus Algorithm

In the DC microgrid with photovoltaic power generations and energy storage systems,because of the photovoltaic power output have the characteristics of randomness and fluctuation,the access of multiple photovoltaic modules will have a great impact on microgrid.At the same time,the distribution location and working status of energy storage units are different,so multiple energy storage units need to be coordinated and controlled.Taking the DC microgrid combined with photovoltaic and energy storage as the research object,aiming at controlling voltage stability of DC bus and realizing reasonable power distribution among energy storage units,this thesis studies the coordinated control strategy of microgrid under the combined operation of photovoltaic and energy storage.The main research contents are as follows.(1)In order to improve the power supply stability of photovoltaic power generation,the maximum power point tracking control strategy based on model predictive control was adopted to control photovoltaic Boost converter.The Perturbation and Observe algorithm is used to ensure that the photovoltaic unit is always working near the maximum power point,and the photovoltaic model is built to verify the advantages of model predictive control.(2)In order to realize the reasonable power distribution among each energy storage unit,the consensus algorithm based on model predictive control strategy is used for energy storage bidirectional DC/DC converter.According to the consensus algorithm,the average voltage observer and the state of charge controller are used to make the energy storage unit maintain the voltage stability and power balance of DC microgrid based on their own state of charge.Furthermore,the disturbance observer based on Luenberger observer is considered to deal with the influence of system error by observing the possible inductance resistance and improve the robustness of the control system.(3)Based on the PSCAD/EMTDC simulation platform,a DC microgrid model was built.The stability of the DC microgrid working under the relevant control mode is verified by simulation based on three different working states.