Energy Management System Applied in DC Electric Springs

Recently, a novel topology of DC electric spring (DCES) was proposed for household application to solve the voltage stability and power quality issues caused by renewable energy source (RES) in DC micorgrids. The novel DCES consists of a DC/DC three port converter (TPC) and energy storage system. The input port of TPC is connected to RES, and a non-critical load (NCL) and a critical load (CL) locate at other two separate ports. The energy storage system paralleled with DC bus where the CL locates, and composed of bi-directional buck-boost converter (BBC) and battery system, is mainly used to ensure the voltage stability and power quality of the CL. This paper proposes an energy management system (EMS) for the novel DCES. The EMS controls the operating mode transition of the BBC, and changes the operating status of the battery system, and realizes multiple charging and/or discharging mechanism. Therefore, the EMS can ensure the voltage stability of CL, maintain the state of charge (SOC) of battery within a reasonable range, extend the battery life and ensure the safe and reliable operation of energy storage system.