Research on capacity allocation of hybrid energy storage system based on improved particle swarm optimisation

In view of optimizing the configuration of each unit's capacity for energy storage in the micro-grid system, in order to ensure that the planned energy storage capacity can meet the reasonable operation of the micro-grid's control strategy, the power fluctuations during the grid-connected operation of the micro-grid are considered in the planning and The economic benefit.of the hybrid energy storage is quantified. This paper uses an improved filter that can dynamically adjust the time constant to distinguish between high frequency and low frequency power fluctuations. Combined with the state of charge and other limiting conditions of the hybrid energy storage system, the target power value of each energy storage unit in the hybrid energy storage is determined.Satisfying the constraint conditions such as the charging and discharging power of the energy storage units,a multi-objective function aiming at minimizing the power fluctuation on the DC bus in the micro-grid and optimizing capacity ratio of each energy storage system in the hybrid energy storage system is established.The improved particle swarm algorithm is used to solve the objective function, and the solution is applied to the micro-grid experimental platform. By comparing the power fluctuations of the battery and the super capacitor in the hybrid energy storage system, the power distribution is directly reflected. Comparing with the traditional mixed energy storage control strategy, it shows that the optimised hybrid energy storage control strategy can save 4.3% of the cost compared with the traditional hybrid energy storage control strategy, and the performance of the power fluctuation of the renewable energy is also improved. It proves that the proposed energy management strategy has certain theoretical significance and practical application value.