Research On Power Cooperative Control And Capacity Optimization Configuration Of Multi-microgrid Hybrid Energy Storage System

With the development of multi-micro grid technology,the proportion of renewable energy power generation in the energy structure is increasing.Due to the complex structure of the multi-microgrid system,the energy storage system of each sub-microgrid needs to be optimally configured,and there is a problem of complex operation power control of the multimicrogrid system.Therefore,this paper studies the coordinated control strategy of the multi-microgrid hybrid energy storage system,establishes the optimal configuration model of the hybrid energy storage capacity,and the improved dynamic droop control algorithm for the distributed supercapacitor of the DC sub-microgrid has good significance.This paper proposes a collaborative control strategy for a multi-microgrid hybrid energy storage system.First,establish a mathematical model of a multi-microgrid system with hybrid energy storage.The lower DC sub-microgrid is equipped with super capacitor banks,and the upper tie bus is equipped with lithium batteries.The filtering algorithm is used to decompose the net load power of each sub-microgrid to obtain each High frequency and low frequency power.When the remaining power of the supercapacitor bank is insufficient,the highfrequency power minus the adjusted remaining power is used as the absorbed power of the supercapacitor bank,and the low-frequency power plus the adjusted power is used as the interactive power delivered to the AC bus,Construct a control strategy for compensating the power of the super capacitor bank.According to the remaining power of the lithium battery and the time-of-use electricity price of the distribution network,a dynamically changing lithium battery charging and discharging performance index and an economic index of purchasing and selling electricity are proposed to calculate the power consumption of the lithium battery and the distribution network,and construct the net load of the AC contact bus.Power allocation strategy.The experimental results show that after the power compensation of the super capacitor bank,the state of charge of the super capacitor bank can meet the requirements of safe work and effectively reduce the net load power fluctuation of the DC bus of the sub-microgrid.After the use of two evaluation indicators to allocate the net load power of the AC bus,the power purchase and sale income of the multi-micro grid system can be significantly improved.The optimization goal is to optimize the investment and construction cost of hybrid energy storage,the penalty cost of DC bus power fluctuation,the revenue from peak shaving and valley filling of lithium battery,and the revenue from purchase and sale of electricity.Optimal allocation model of hybrid energy storage capacity based on comprehensive daily operating costs.The differential evolution algorithm is used to optimize the configuration of hybrid energy storage capacity,and the experimental results prove the effectiveness of the built model for optimal configuration of hybrid energy storage capacity.Research an improved dynamic droop control algorithm for flexible control of distributed supercapacitors.By analyzing the positive correlation between the droop coefficient and the DC bus voltage offset,the dynamic droop coefficient is adaptively changed according to the DC bus net load power,and an adaptive dynamic droop control algorithm is proposed to reduce the DC bus voltage fluctuation.By analyzing the negative correlation between the droop coefficient and the charging and discharging power of the distributed supercapacitor,an improved adaptive dynamic droop control algorithm that takes into account the remaining power of the distributed supercapacitor is proposed.On the one hand,according to the total remaining power of the supercapacitor bank,construct The auxiliary parameter of the improved dynamic droop coefficient.On the other hand,by analyzing the remaining power of each distributed supercapacitor,the consistent equalization coefficient of the improved dynamic droop coefficient is obtained,and the adaptive dynamic droop coefficient is improved through these two parameters.Continuously adjust the output power of distributed supercapacitors.The simulation results show that the improved dynamic droop control algorithm can accurately control the output power of distributed supercapacitors,and effectively improve the flexibility and reliability of distributed supercapacitor control.