Remaining-battery-capacity estimating apparatus, remaining-battery-capacity estimating method, and remaining-battery-capacity estimating computer program
A remaining-battery-capacity estimating apparatus estimates the remaining capacity of a battery used as a backup. The apparatus reduces the voltage output from a rectifier to an actual load, measures current flowing from the rectifier and the battery to the actual load and a dummy load device provided separately from the actual load, controls the load of the dummy load device such that the measured current is a predetermined value, and calculates the remaining capacity of the battery based on the terminal voltage of the battery and the discharging time of discharging the battery to the actual load and the dummy load device, by referring to battery data indicating the relationship among the discharging time of the battery, the terminal voltage of the battery, and the remaining capacity of the battery, at a predetermined current of the battery.
1. A remaining-battery-capacity estimating apparatus for estimating a remaining capacity of a battery to be measured, comprising:
a rectifier that is connected in parallel to the battery to be measured, and supplies electric power to an actual load;
an actual load connected in parallel to the rectifier, wherein the rectifier supplies electric power to the actual load;
a rectifier-voltage control section that reduces an output voltage of the rectifier;
a dummy load device provided separately from the actual load and connected in parallel to the rectifier;
a load-current measurement section that measures current that flows through the actual load and the dummy load device from the rectifier and the battery;
a control section that controls a load of the dummy load device such that the current measured by the load-current measurement section is a predetermined value;
a battery-data storage section that stores battery data indicating relationship among a discharging time of the battery, a terminal voltage of the battery, and remaining capacity of the battery, at a predetermined current of the battery; and
an arithmetic section that calculates the remaining capacity of the battery based on the discharging time of a discharging current flowing through the dummy load and the actual load, and the terminal voltage of the battery corresponding to the discharging current at the discharging time by referring to the battery data stored in the battery-data storage section.
2. The remaining-battery-capacity estimating apparatus according to claim 1 , wherein the battery data indicating the relationship is one between the remaining capacity of the battery and difference between a discharge terminal voltage of the battery at a given discharging current at a given elapsed discharging time and a charge terminal voltage of the battery maintained in a state where the battery is charged, before discharging.
3. The remaining-battery-capacity estimating apparatus according to claim 1 , wherein the battery data indicating the relationship is one between the remaining capacity of the battery and difference between a reference terminal voltage of the battery in a reference charged state and a discharge terminal voltage of the battery in a discharged state, at a given discharging current at a given elapsed discharging time.
4. The remaining-battery-capacity estimating apparatus according to claim 1 , wherein the battery data indicating the relationship is one between the terminal voltage of the battery and an elapsed discharging time of the battery for each remaining capacity of the battery.
5. The remaining-battery-capacity estimating apparatus according to claim 1 , wherein the battery data stored in the battery-data storage section stores includes at least one of manufacturers, suppliers, production lots, models, temperatures, discharging current values, and elapsed discharging time of the battery, for each discharging condition.
6. The remaining-battery-capacity estimating apparatus according to claim 1 , wherein the rectifier-voltage control section stops reducing the voltage output from the rectifier when the voltage of the battery decreases to a predetermined value while electrical power is supplied from the battery to the actual load and the dummy load device.
7. The remaining-battery-capacity estimating apparatus according to claim 2 , wherein the rectifier-voltage control section stops reducing the voltage output from the rectifier when the voltage of the battery decreases to a predetermined value while electrical power is supplied from the battery to the actual load and the dummy load device.
8. The remaining-battery-capacity estimating apparatus according to claim 3 , wherein the rectifier-voltage control section stops reducing the voltage output from the rectifier when the voltage of the battery decreases to a predetermined value while electrical power is supplied from the battery to the actual load and the dummy load device.
9. The remaining-battery-capacity estimating apparatus according to claim 4 , wherein the rectifier-voltage control section stops reducing the voltage output from the rectifier when the voltage of the battery decreases to a predetermined value while electrical power is supplied from the battery to the actual load and the dummy load device.
10. The remaining-battery-capacity estimating apparatus according to claim 5 , wherein the rectifier-voltage control section stops reducing the voltage output from the rectifier when the voltage of the battery decreases to a predetermined value while electrical power is supplied from the battery to the actual load and the dummy load device.
11. A remaining-battery-capacity estimating method for estimating a remaining capacity of a battery to be measured, comprising the steps of:
reducing an output voltage of a rectifier that is connected in parallel to the battery to be measured, and supplies electrical power to an actual load;
measuring current flowing through the actual load and a dummy load device provided separately from the actual load from the battery and the rectifier;
controlling the dummy load device such that the measured current is a predetermined value; and
calculating remaining capacity of the battery based on a discharging time of the battery and a discharge terminal voltage of the battery corresponding to the discharging time, at a discharging current flowing through the dummy load device and the actual load device, by referring to a battery-data storage section that stores battery data indicating a relationship among the discharging time of the battery, the terminal voltage of the battery, and the remaining capacity of the battery, at a predetermined current of the battery.
12. A computer program product for causing a computer in the remaining-battery-capacity estimating apparatus according to claim 1 , said computer program product stored on a computer readable medium and including a program code for estimating the remaining capacity of the battery to be measured, to function as:
means for reducing an output voltage of a rectifier that supplies electrical power to an actual load;
means for measuring current that flows through the actual load and a dummy load device provided separately from the actual load from the rectifier and the battery;
means for controlling a load of the dummy load device such that the measured current is a predetermined value; and
means for calculating the remaining capacity of the battery based on a discharging time of the battery and a discharge terminal voltage of the battery corresponding to the discharging time, at a discharging current flowing through the dummy load device and the actual load, by referring to a battery-data storage section for storing battery data indicating a relationship among the discharging time of the battery, the terminal voltage of the battery, and the remaining capacity of the battery, at a predetermined current of the battery.