一种基于级联Buck-Boost变换器的多储能并联系统及其控制策略设计

A multi-storage parallel system based on cascaded Buck-Boost converter and its control strategy design

储能单元是直流微电网可靠运行需要解决的关键环节,传统的双向Buck-Boost变换器在电压增益及成本等方面不具有优势,因此需要新的设计方案。首先,以基于级联型Buck-Boost变换器的储能系统为研究对象,提出级联Buck-Boost变换器作为子模块的系统设计方案;然后,通过对级联Buck-Boost变换器的工作模态分析,确定其在Buck和Boost模式下的电压增益,并给出调制策略,同时结合直流微网运行模式,进一步提出储能系统的整体运行方案,在不同的工况下采用合适的控制策略来维持微网的可靠运行;最后,搭建相关仿真验证了所设计的储能系统和控制方案的有效性。

Energy storage unit is one of the key factorswhichcan ensure the reliable operation of DC microgrids.Traditional bi-directional Buck-Boost convertershave no advantages in voltage gain regulation and the correspondingcost,so a new design scheme is required to make a trade-off between the regulation capability and cost.First,for the energy storage system based on cascaded Buck-Boostconverter,this paper proposesa system-level design scheme whichusing cascaded Buck-Boostconverter as the sub module.Then,the voltage gain regulation of the cascaded Buck-Boostconverter in Buck and Boost mode is investigated by analyzing the working mode,and the modulation strategy is proposedfor the cascaded Buck-Boostconverter.At the same time,with the consideration of the operation mode of DC microgrid,the overall operation strategiesof energy storage system arefurther proposed to enable the storage to adoptthe appropriate control strategy to securethe reliable operation of microgrid under different working conditions.Finally,the effectiveness of the designed energy storage system and the control strategy areverified by several simulations.