Research On Control Strategy And Location And Capacity Determination Of Energy Storage System In Microgrid

Wind power,photovoltaic power and other new energy power generation technologies have entered a stage of rapid development under the key support of the state,and the development of microgrids has attracted great attention from all countries.However,the uncertainty,volatility,anti disturbance and poor overload capacity of the output power of wind,light and other micro power sources have adverse effects on the power supply quality of micro grid and the access to large power grid.The reasonable energy storage system control strategy and location and capacity determination scheme can realize the efficient energy transfer among the modules of the microgrid,cut peak and fill valley,and improve the anti-interference ability of the distribution network.In view of this,this paper studies and analyzes the control strategy of energy storage system and the determination of its access location and capacity.The main research methods and conclusions are as follows:(1)Wind,light,and storage operation characteristics analysis.The working principle of wind and light micro power supply is analyzed and the simulation model is established.The influence of meteorological conditions(light intensity,temperature and wind speed)on its output power is studied.The maximum power tracking of wind and light output is realized.The circuit models of battery and super capacitor and their working characteristics are studied and analyzed,which provides a theoretical basis for the control strategy of energy storage system and the research of location and capacity.(2)Research on non-linear control strategy of storage battery charging and discharging.According to the constraints of power balance of microgrid,the output rule of battery is obtained.Based on modern mathematics and control theory,a nonlinear control strategy is proposed to coordinate the power transmission between the micro grid systems by rectifying circuit.The simulation results show that: compared with PI control strategy,the recovery time of the proposed control strategy is reduced by 0.2 s,and the DC bus voltage impulse fluctuation is reduced by 0.6%.The results show that the proposed control strategy can effectively suppress the output fluctuation and improve the system stability.(3)Research on power allocation strategy and PI parameter tuning of hybrid energy storage system.The state of charge of the super capacitor and the reference power of the battery are taken as the control objectives to achieve the coordinated distribution of fluctuating power in the network;According to the ideal phase angle margin of industrial control,the PI controller is designed automatically by using Siso feedback technology to adjust the error between the actual value and the reference value.Simulation tests under environmental changes and normal load fluctuations show that the PI controller adjusted by Siso feedback enables the proposed control strategy to more effectively smooth the fluctuating power,while smoothing the instantaneous output of the battery and reducing the number of charge and discharge switches.Maintain the DC bus voltage fluctuation value ≤ 5%,shortening its dynamic recovery time.(4)Research on location and capacity of energy storage system.Aiming at the problem of location and capacity of energy storage system after microgrid is connected to distribution network,particle swarm optimization algorithm combined with ordinal preference method is used to solve the multi-objective optimization model of location and capacity of energy storage system.Considering the output characteristics of distributed generation in different seasons,the IEEE-33 node microgrid system is constructed for example analysis.According to the output law of photovoltaic and wind power in southwest Xinjiang in different seasons,the energy storage access location and capacity configuration scheme are solved.The results show that the method can find the optimal solution in different seasons.It avoids the limitation of the location and capacity scheme under single season solution.