A Filter-Modulated Droop Control for Hybrid Energy Storage System in DC Microgrid

The hybrid energy storage system has been proved practical and widely utilized in renewable energy generation. Nonetheless, the implementation of dynamic power allocation among different storage units is challenging. In this paper, a decentralized current splitting strategy is proposed for a battery/supercapacitor hybrid system in DC microgrid. The design adopts a frequency domain function with one-order filter characteristic to reshape the droop coefficient curve. By taking this approach, battery provides steady-state components of the power imbalance and supercapacitor compensates the transient power fluctuations. Simulations and experiments are conducted to validate effectiveness of the proposed method.