Patent ID: 7777446

Claim:
An apparatus for controlling a voltage of power on a power-supplying line extending from an on-vehicle generator and connecting to an on-vehicle battery and on-vehicle eclectic loads, the apparatus being mounted on a vehicle, the apparatus comprising: a detecting device detecting pairs of voltage and current of the battery repeatedly at intervals; a calculator calculating a control current based on the detected pairs of voltage and current and a target voltage given to the voltage of the power; and a controller controlling a charge and discharge current of the battery based on the control current such that the voltage of the power is controlled at the target voltage, wherein the calculator is provided with internal resistance obtaining means for obtaining an internal resistance of the battery based on the pairs of voltage and current; first calculating means for calculating a value of the control current based on the target voltage and the internal resistance; first providing means for providing the control current as a command to the controller; first determining means for determining whether or not an error between an actual voltage of the battery and the target voltage is within an allowable range; regression line obtaining means for obtaining a regression line defining a relationship between the voltage and the current of the battery by using the pairs of voltage and current if it is determined by the first determining means that the error is within the allowable range; second calculating means for re-calculating a value of the control current based on the target voltage and the regression line; and second providing means for re-providing the control current as the command to the controller.