| 摘要 |
<p>A power supply device includes a power conversion circuit, a secondary battery, a table, and a control circuit. The power conversion circuit converts alternating-current or direct-current power into direct-current power to supply power to a load. The secondary battery is connected between the power conversion circuit and the load and charged with power from the power conversion circuit so that power is supplied to the load when the charging power is discharged. On the table, power conversion efficiency of the power conversion circuit associated with output power and charging efficiency of the secondary battery associated with charging power are recorded. The control circuit looks up the table to calculate power loss, which is based on the power conversion efficiency of the power conversion circuit associated with the output power in the case where power is supplied from the power conversion circuit to the load, and power loss, which is based on the charging efficiency of the secondary battery associated with the charging power in the case where power is output from the power conversion circuit so that the power conversion efficiency is at the highest level and the secondary battery is charged with extra power that is left after power is supplied to the load, makes a determination, on the basis of both the calculated power losses, as to whether the supply of power from the secondary battery to the load leads to a smaller power loss, makes a determination, when the supply of power from the secondary battery to the load leads to a smaller power loss, as to whether there is a remaining capacity in the secondary battery, and performs a control process, when there is no remaining capacity in the secondary battery, so that power is supplied from the power conversion circuit to the load and the secondary battery is charged for a predetermined period of time.</p> |
