Dc backup power system

A Direct Current (DC) backup power system, comprising a three-port module and an energy storage battery, wherein:

• the three-port module comprises a rectifier unit and a charging and discharging unit, wherein the rectifier unit is connected to the charging and discharging unit, the charging and discharging unit is connected to the energy storage battery, and an output end of the rectifier unit is connected to a load;
• the rectifier unit is configured to convert external alternating current into direct current to supply power to the load, charge the energy storage battery through the charging and discharging unit, and output the electric energy of the energy storage battery to supply power to the load after the external alternating current is disconnected;
• the rectifier unit comprises a filter, a power factor correction circuit and a DCDC converter which are connected in sequence;
• a first end of the energy storage battery is connected to a first output end of the DCDC converter, and a second end of the energy storage battery is connected to a second output end of the DCDC converter through the charging and discharging unit.