TECHNICAL FIELD

The present disclosure relates to a method for controlling a discharge of an electric charge stored in a capacitor of a power storage device.

BACKGROUND

Heretofore, there has been known a discharge circuit for discharging power charged in a capacitor in a power conversion apparatus such as an inverter apparatus.

As an example of this type of discharge circuit, a constant power discharge circuit is disclosed (refer to Unexamined Japanese Patent Publication No. 2009-112156). The constant power discharge circuit includes: a transistor capable of adjusting a discharge current by a gate voltage; and a shunt resistor that allows a flow of the discharge current adjusted by the transistor and outputs a reference voltage. The constant power discharge circuit decides discharge current setting values in response to a discharge voltage that gradually decreases due to the discharge. Moreover, the constant power discharge circuit compares one of the discharge current setting values selected in response to a residual voltage of the capacitor and the discharge current obtained from the reference voltage with each other and controls the gate voltage such that the discharge current becomes equal to the discharge current setting value.

SUMMARY

A method for controlling a discharge of a power storage device, the power storage device including a power storage and a discharge circuit, the method includes: a first step of discharging, in a first section of a discharging period, a part of an electric charge stored in the power storage through a first discharge path and a second discharge path which are included in the discharge circuit; and a second step of discharging, in a second section of the discharging period, a remaining part of the electric charge stored in the power storage through the second discharge path. The first discharge path includes a zener diode connected to one end of the power storage. The second discharge path includes a first transistor connected to the one end of the power storage at a first input terminal of the first transistor. The first section is a period in which a voltage of the one end of the power storage is higher than a breakdown voltage of the zener diode. The second section is a period in which a voltage of the one end of the power storage is lower than the breakdown voltage of the zener diode. An output current of the first transistor in the second section is greater than an output current of the first transistor in the first section.

In accordance with the present disclosure, a control of the discharge of the power storage device that performs discharge approximating constant power discharge can be realized with a simple configuration. Accordingly, a power storage device capable of decreasing size and cost can be implemented.

