Method and apparatus for calculating battery state and apparatus for controlling power voltage in vehicle

Abstract

An apparatus is provided to control a power voltage on a power-supplying line extending from a generator and connecting to a battery and eclectic loads. The apparatus is mounted on a vehicle and comprises a detecting device, a calculator, and a controller. The detecting device detects pairs of voltage and current of the battery. The calculator calculating a control current on the basis of the detected pairs of voltage and current and a target voltage for the power voltage. The pairs of voltage and current are used to calculate an internal resistance and/or a regression line of the battery. The controller controlling a charge and discharge current of the battery on the basis of the control current so that the power voltage is controlled to the target voltage.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is a schematic diagram showing the configuration of an on-vehicle power supply system according to a first embodiment of the present invention;

FIG. 2 is a flowchart outlining the processing carried out by a battery controller in the first embodiment;

FIG. 3 is a timing chart showing sampling of voltage and current of a battery and calculation in the battery controller;

FIGS. 4-6 are flowcharts each outlining the processing carried out by a battery controller in the first embodiment;

FIG. 7 is a graph explaining a shift operation of a regression line;

FIG. 8 is a schematic diagram showing the configuration of an on-vehicle power supply system according to a modification of the first embodiment;

FIGS. 9 and 10 are flowcharts each outlining the processing carried out by a battery controller in a second embodiment according to the present invention; and

FIGS. 11 and 12 illustrate previously set and determined various regression lines which are subjected to selection in the second embodiment.

Claims

1. An apparatus for controlling a power voltage (VL) on a power-supplying line (5) extending from a generator (7, 7A) and connecting to a battery (1) and eclectic loads (L), the apparatus being mounted on a vehicle (VE), the apparatus comprising: a detecting device (6, 6A) detecting pairs of voltage and current of the battery;a calculator (3) calculating a control current on the basis of the detected pairs of voltage and current and a target voltage for the power voltage; anda controller (2, 7B) controlling a charge and discharge current of the battery on the basis of the control current so that the power voltage is controlled to the target voltage.

2. The apparatus of claim 1, wherein the calculator (3) is provided with means (step S111) for obtaining a regression line of the battery based on the pairs of voltage and current and the target voltage;means (steps S114-S117, S103, S104) for regularly updating the regression line by using the pairs of voltage and current measured at intervals through the detecting device;means (steps S112-S113) for calculating a value of the control current on the basis of the target voltage and the regression line updated regularly; andmeans (step S113) for providing the control current as a command to the controller (2).

3. The apparatus of claim 1, wherein the calculator (3) is provided with means (steps S103-S105) for obtaining an internal resistance of the battery using the pairs of voltage and current measured through the detecting devicefirst means (steps S106-S107) for calculating a value of the control current on the basis of the target voltage and the internal resistance; andfirst means (steps S107) for providing the control current as a command to the controller (2).

4. The apparatus of claim 3, wherein the calculator (3) is provided with first means (steps S108-S109) for determining whether or not an error between an actual voltage of the battery and the target value is within an allowable range;first means (steps S108, S111) for obtaining a regression line of the battery by using the pairs of voltage and current measured through the detecting line, if it is determined that the error is within the allowable range;second means (steps S112-S113) for re-calculating a value of the control current on the basis of the target voltage and the regression line; andsecond means (step S113) for re-providing the control current as a command to the controller (2).

5. The apparatus of claim 4, wherein the calculator (3) is provided with second means (steps S114-S115) for determining whether or not an error between an actual voltage of the battery and the target value is within the allowable range;means (step S118) for shifting the regression line to a new regression line based on a latest pair of voltage and current measured through the detecting device, if it is determined that the error is within the allowable range;third means (steps S119-S120) for re-calculating a value of the control current on the basis of the target voltage and the shifted regression line; andthird means (step S120) for re-providing the control current as a command to the controller (2).

6. The apparatus of claim 5, wherein the calculator (3) is provided with third means (steps S121-S122) for determining whether or not an error between an actual voltage of the battery and the target value is within the allowable range;means (step S123) for amending a slope of the shifted regression line, if it is determined by the third determining means that the error is within the allowable range;forth means (steps S116, S117, S103, S104, S112, S113) for re-calculating a value of the control current on the basis of the target voltage and the shifted and slope-amended regression line; andfourth means (step S113) for re-providing the control current as a command to the controller (2).

7. The apparatus of claim 1, wherein the calculator (3) is provided with first means (step S111) for obtaining a regression line of the battery based on the pairs of voltage and current and the target voltage;first means (steps S119-S120) for calculating a value of the control current on the basis of a target voltage and the regression line;first means (step S120) for providing the control current as a command to the controller (2);means (steps S114-S115) for determining whether or not an error between an actual voltage of the battery and the target value is within an allowable range;means (step S118) for obtaining a further regression line of the battery based on the pairs of voltage and current and the target voltage, if it is determined that the error is within the allowable range;second means (steps S119-S120) for calculating a further value of the control current on the basis of the target voltage and the further regression line; andsecond means (step S120) for providing the further control current as a command to the controller (2).

8. The apparatus of claim 1, wherein the calculator (3) is configured to obtain a plurality of regression lines of the battery on the pairs of voltage and current and the target voltage; calculate a value of the control current on the basis of a target voltage and at least one of the regression lines; and provide the control current as a command to the controller (2).

9. The apparatus of claim 8, wherein the calculator (3) is configured to determine whether or not an error between an actual voltage of the battery and the target value is within an allowable range and selectively use one of the regression lines in calculating the value of the control current.

10. The apparatus of claim 8, wherein the calculator (3) is provided with first means (step S111) for obtaining a regression line of the battery based on the pairs of voltage and current and the target voltage;first means (steps S119-S120) for calculating a value of the control current on the basis of a target voltage and the regression line;first means (step S120) for providing the control current as a command to the controller (2);means (steps S114-S115) for determining whether or not an error between an actual voltage of the battery and the target value is within an allowable range;means (step S118) for obtaining a further regression line of the battery based on the pairs of voltage and current and the target voltage, if it is determined that the error is within the allowable range;second means (steps S119-S120) for calculating a further value of the control current on the basis of the target voltage and the further regression line; andsecond means (step S120) for providing the further control current as a command to the controller (2).

11. The apparatus of claim 1, wherein the controller (2) is arranged separately from the generator (7) and arranged in a path connecting the power-supplying line and the battery.

12. The apparatus of claim 1, wherein the controller (7B) is arranged in the generator (7A).

13. The apparatus of claim 1, wherein the calculator (3) is configured to obtain a regression line of the battery on the pairs of voltage and current and the target voltage; calculate a value of the control current on the basis of a target voltage and at least one of the regression lines; provide the control current as a command to the controller (2); determine whether or not an error between an actual voltage of the battery and the target value is within an allowable range; and amend the regression line, if it is determined the error is not within the allowable range.

14. The apparatus of claim 13, wherein the calculator (3) is configured to amend a slop angel of the regression line so as to make the error smaller.

15. An apparatus for calculating an electric quantity indicating a state of a battery (1) being mounted on a vehicle (VE), the battery being connected via a line (5) to a generator (7, 7A) and electric loads (L), the apparatus comprising: a detecting device (6, 6A) detecting pairs of voltage and current of the battery; anda calculator (3) configured to calculate a first regression line on the basis of the pairs of voltage and current, determine whether or not the first regression line is sufficient or not; shift the first regression line to a second regression line based on a pair of voltage and current measured through the detecting device, if it is determined that the first regression line is not sufficient; and calculate an electric quantity based on the second regression line.

16. The apparatus of claim 15, wherein the calculator (3) is configured to shift the first regression line so that a shifted distance from the first regression line to the second regression line is the shortest.

17. The apparatus of claim 15, wherein the calculator (3) is configured to calculate, as the electric quantity, a current of the battery by applying a voltage of the batter to the second regression line.

18. The apparatus of claim 15, wherein the calculator (3) is configured to calculate, as the electric quantity, a voltage of the battery by applying a current of the batter to the second regression line.

19. A method of calculating an electric quantity indicating a state of a battery (1) being mounted on a vehicle (VE), the battery being connected via a line (5) to a generator (7, 7A) and electric loads (L), the method comprising steps of: determining whether the battery is in a discharge state or in a charge state;selecting one regression line (RG1, RG2, RG3 or RG4) depending on a determined result by the determining step, from a plurality of types of regression lines (RG1, RG2, RG3 and RG4)prepared beforehand depending on the battery is in the discharge state or the charge state; andcalculating the electric quantity by using the selected one regression.

20. The method of claim 19, wherein the plurality of types of regression lines are four regression lines consisting of a first regression line used when the battery is in the discharge state and a current of the battery is on the increase (RG1), a second regression line used when the battery is in the discharge state and the current of the battery is on the decrease (RG2), a third regression line used when the battery is in the charge state and the current of the battery is on the increase (RG3), and a fourth regression line used when the battery is in the charge state and the current of the battery is on the decrease (RG4).