| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an energy storage device that accurately offsets a charge amount Q of a capacitor. Ž<P>SOLUTION: The energy storage device includes an energy storage unit 13 comprising a capacitor, a charge and discharge circuit 15 and a voltage detect circuit 17 both connecting with the energy storage unit 13, a current detection circuit 19 connecting with the energy storage unit 13 in series, and a control circuit 23 connecting with the charge and discharg circuit 15, the voltage detect circuit 17, and the current detection circuit 19. The control circuit 23 accumulates the current I of the energy storage unit 13 at a predetermined time interval Δt for obtaining the charge amount Q of the energy storage unit 13 and also obtains a capacitance value Cc at charging and a capacitance value Cd at discharging from an average battery charge current Ic and an average electric discharge current Id of the energy storage unit 13 in a preceding predetermined period of time t based on the correlation of the current I and the capacitance value C of the energy storage unit 13 when the current I is practically 0 so that the offset charge amount Qc gained by multiplying the average values Cm by the voltage Vc of the energy storage unit 13 is updated as the charge amount Q for offset. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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