Research On Control Strategy Of Hybrid Energy Storage System Based On DC Micro Grid

As the fossil energy exhausting,Distributed energy is given priority to with wind and photovoltaic(Distributed energy resources,DER)generation become one of research hot spots,but power units restricted by power generation environment is more,the output power of randomness,volatility and discontinuity is bigger,lead to the Distributed energy after detail when grid power efficiency is low,reduce the stability of the power of micro grid system and power quality.With the continuous development of energy storage technology,the power throughput function of energy storage components can effectively improve the power fluctuations caused by DER grid-connection.However,the traditional single energy storage components have high limitations and cannot solve the impact on the power grid when the power fluctuations are large.Therefore,this paper takes the 10 k V DC micro-grid as the research object,takes the photovoltaic power generation system as the energy supply object,takes the battery-supercapacitor hybrid energy storage system as the energy storage object,and aims to improve the energy supply stability of the micro-grid system,and studies the control strategy of each component of the hybrid energy storage system.Through the corresponding control strategy,the energy storage unit can effectively absorb the power fluctuations generated by the generation unit and improve the power quality of the micro-grid.Based on distributed power or power fluctuation problem caused load mutation,in micro grid system is introduced in the hybrid energy storage system to smooth power fluctuation,improve the stability of the micro power grid system,combining the merits of the energy storage unit,a storage battery,super capacitor hybrid energy storage system structure,and put forward corresponding control unit of the hybrid energy storage system of the control strategy,aimed at the system level,the double low pass filter is proposed based on prediction of direct power control strategy,through the double low pass filter,the power fluctuation is decomposed into high frequency component and low frequency component,storage battery as a type of energy storage component,has the high energy density,Can effectively absorb low-frequency component,the super capacitor as a power type energy storage device,high power density,rapid response speed,can effectively absorb the high frequency wave,reduce the influence of power fluctuations on power system stability,and reuse the forecasting direct power control algorithm,to predict the next control cycle power range,make a DC/DC converter are prepared ahead of time wave and control,to improve the transient response speed of the hybrid energy storage system.In equipment level for super capacitor,this paper proposes a based on improved particle swarm optimization(pso)algorithm of double closed loop fuzzy PI control,power distribution of the objective function are obtained by improved particle swarm algorithm the optimal solution,again through the fuzzy PI control,quadratic optimization,get more accurate power allocation parameters,and optimal power control signal is obtained by going to blur,and through the PI controller to control the bidirectional DC/DC converter,thus increasing the response rate of the super capacitor and transient characteristics,greatly improve the super capacitor’s capacity to absorb high frequency partial wave,prolong the service life of battery recycling,Increase the ability of the hybrid energy storage system to suppress power fluctuations,so that the microgrid can bear more distributed electricity grid connection,and indirectly promote the development and utilization of clean energy.