Research on asymmetric hybrid cascade multilevel energy storage System based on Battery-Supercapacitor

In recent years, battery-supercapacitor hybrid energy storage systems have been widely used in distributed power generation systems. Battery and supercapacitor have different energy storage characteristics but are highly complementary. Compared with the system using a single energy storage element, the hybrid energy storage system combined with batteries and supercapacitors can better meet the requirements of high power density and high energy density at the same time. In this paper, a novel asymmetric hybrid cascaded multilevel energy storage system based on battery-supercapacitor is proposed. Its topology is mainly composed of the hybrid cascaded three-phase inverter and H bridge. For this topology, a corresponding hybrid level shifted pulse-width modulation (PWM) (HLS-PWM) scheme is proposed, which can be divided into Ms mode and Mo mode according to the output power directions of the battery and supercapacitor. Combined with the energy storage characteristics of battery-supercapacitor, four working modes and an overall energy management strategy are proposed. Finally, the simulation results verify the superiority of the proposed asymmetric hybrid cascaded energy storage system and its energy management strategy.