Direct current (DC) microgrid charge/discharge system for secondary batteries connected in series

摘要

An algorithm and a direct current (DC) microgrid charge/discharge system with the algorithm are provided that noticeably increases charge/discharge voltage during charging and discharging by connecting a plurality of secondary batteries in series, compared to a single battery, that increases power conversion efficiency of a DC-to-DC (DC/DC) converter for charge/discharge power control by setting an appropriate voltage of a DC microgrid to be about twice a maximum voltage of a battery group, that enables charging and discharging to be stably performed regardless of a change in the battery group by adding a linear constant current source, that increases power conversion efficiency of the DC microgrid charge/discharge system by configuring a DC energy storage system (ESS) used for both charging and discharging with a combination of a typical electrolytic condenser and a super condenser or a group of the secondary batteries, and that simplifies the DC microgrid charge/discharge system.

主权项

1. A direct current (DC) microgrid charge/discharge system for a plurality of secondary batteries that are connected in series, the DC microgrid charge/discharge system comprising:
a linear current source configured to permit charging and discharging of the plurality of secondary batteries; a single bidirectional DC-to-DC (DC/DC) converter configured to supply power to the plurality of secondary batteries for charging of the plurality of secondary batteries and to permit discharging of the plurality of secondary batteries at a high power conversion efficiency, wherein the linear current source is located between the bidirectional DC/DC converter and the plurality of secondary batteries, and wherein the bidirectional DC/DC converter operates at a voltage that is higher than a voltage of a single battery among the plurality of batteries; and a DC energy storage system (ESS) to stably supply power to the bidirectional DC/DC converter, the DC ESS being disposed in a front side of the bidirectional DC/DC converter, wherein the DC ESS supplies power during power outage.