Distributed Cooperative Control for Multiple DC Electric Springs with Novel Topologies Applied in DC Microgrid

DC electric spring (DCES) has been proposed for improving the power quality and voltage stability of DC microgrid. In this paper, a distributed cooperative control is applied for multiple DCESs with the recently proposed novel topology. The novel DCES is composed of DC/DC three port converter (TPC), bi-directional buck-boost converter (BBC) and battery system, while the BBC and battery system form the energy storage system of DCES. The distributed cooperative control for multiple DCESs, including the primary control and secondary control, is mainly used to realize the power allocation of multiple DCESs, local voltage stability and the consensus of DC-bus voltages and state-of-charges (SOCs) of battery among DCESs. The primary voltage control, including the phased-shift control, decoupling control and droop control, is used to regulate the local voltage of each DCES. The secondary control based on consensus algorithm, including control of DC-bus voltage and battery SOC, can regulate the DC-bus voltage reference and realize the SOC balance of batteries among DCESs.