State-of-charge estimation apparatus

摘要

A state-of-charge estimation apparatus connected to a power storage device having cell batteries, and estimating a state of charge of the power storage device, the apparatus including a first SOC computation unit computing a current integration value based on a total current from a current detector detecting the total current flowing to the storage device from a power conversion device using a previous SOC value as an initial value, and outputting the integration value as a first state-of-charge estimated value, and a second SOC computation unit estimating, after discharge suspension in the storage device, an open-circuit voltage based on a total voltage on a connection point between the conversion device and the storage device, a previous value of the total voltage, and a gain with time passage after discharge suspension in the storage device, and outputting the open-circuit voltage as a second state-of-charge estimated value.

主权项

1. A state-of-charge estimation apparatus that is connected to a power storage device constituted by connecting a plurality of cell batteries, and estimates a state of charge of the power storage device, the state-of-charge estimation apparatus comprising:
a first computation unit that computes a current integration value based on a current from a detector that detects a current flowing to or from the power storage device from or to a power conversion unit while a previous value of a state-of-charge estimated value is set as an initial value, and that outputs the computed current integration value as a first state-of-charge estimated value; a second computation unit that includes a gain unit that gives a predetermined gain to a difference between a voltage detected in a connection point between the power conversion unit and the power storage device and a previous value of the voltage detected in the connection point, estimates an open-circuit voltage based on an output from the gain unit and the previous value of the voltage detected in the connection point, and outputs the open-circuit voltage as a second state-of-charge estimated value; and a selection unit that selects any one of the first state-of-charge estimated value and the second state-of-charge estimated value, wherein the predetermined gain is set to be a large value during a predetermined period in which the voltage suddenly changes after suspension of charge or discharge in the power storage device, and to decrease to be a final value that is smaller than 1 after passage of the predetermined period, and the second computation unit estimates the open-circuit voltage using the predetermined gain when a current command outputted from the power conversion unit indicates suspension of the charge or discharge in the power storage device.