Electric power supply device, method for supplying electric power, and power storage device

1. An electric power supply device comprising:

a first switch interposed between an electric power system and a predetermined load;

a power storage system having a secondary battery, a first charging and discharging unit interposed between the secondary battery and the electric power system, and a second charging and discharging unit interposed between the secondary battery and the predetermined load; and

a controller configured to control the first switch, the first charging and discharging unit, and the second charging and discharging unit,

wherein the controller causes the first switch to open to disconnect between the electric power system and the predetermined load, causes the first charging and discharging unit to perform reverse power flow for a prescribed time, and causes the second charging and discharging unit to supply electric power to the predetermined load when system abnormality occurs.

2. The electric power supply device according to claim 1 , wherein the controller is configured to control each of the first charging and discharging unit and the second charging and discharging unit to be in one of a discharging operation, a charging operation, and a charging and discharging stopping state.

3. The electric power supply device according to claim 1 , further comprising a reverse power flow monitoring device, wherein the controller is configured to control discharge electric power of the second bidirectional conversion device to be equal to or less than power consumption of the predetermined load.

4. The electric power supply device according to claim 1 , further comprising a dispersed power source connected between the electric power system and the first switch.

5. The electric power supply device according to claim 1 , wherein when the system abnormality does not continue, the first switch is closed, and when the system abnormality continues, the first switch remains opened.

6. The electric power supply device according to claim 1 , further comprising:

a second switch connected between the electric power system and the first switch; and

a load connected between the first switch and the second switch, together with the first charging and discharging unit,

wherein

when system abnormality occurs, the controller causes the first switch to open to disconnect between the electric power system and the predetermined load, causes the first charging and discharging unit to perform reverse power flow for a prescribed time, and causes the second charging and discharging unit to supply electric power to the predetermined load,

when the system abnormality does not continue, the controller causes the first switch to close, and

when the system abnormality continues, the controller causes the first switch to remain opened, and the second switch to open from a closed state, and the first charging and discharging unit supplies electric power to the load through the second switch.

7. The electric power supply device according to claim claim 6 , further comprising a dispersed power source connected between the first switch and the second switch, wherein the dispersed power source is configured to charge the secondary battery through the first charging and discharging unit while the other switch is opened.

8. The electric power supply device according to claim 7 , wherein the dispersed power source includes a solar cell device.

9. A method for supplying electric power of an electric power supply device including: a first switch interposed between an electric power system and a predetermined load; a power storage system having a secondary battery, a first charging and discharging unit interposed between the secondary battery and the electric power system, and a second charging and discharging unit interposed between the secondary battery and the predetermined load; and a controller configured to control the first switch, the first charging and discharging unit, and the second charging and discharging unit, the method comprising the steps of:

when system abnormality occurs, opening the first switch to disconnect between the electric power system and the predetermined load; causing the first charging and discharging unit to perform reverse power flow for a prescribed time; and causing the second charging and discharging unit to supply electric power to the predetermined load.