Power supply system and voltage control method for fuel cell
First Claim
1. A voltage control method for a fuel cell in a power supply system including the fuel cell configured to supply an electric power to a load, the voltage control method comprising:
- interrupting an electrical connection between the fuel cell and the load when the load is in a low load state where the electric power required by the load is less than or equal to a predetermined reference value;
supplying oxygen to the fuel cell based on a preset condition when the electrical connection between the fuel cell and the load is interrupted, the preset condition being a condition for supplying the fuel cell with oxygen required to adjust an open circuit voltage of the fuel cell to a predetermined target voltage;
detecting the open circuit voltage of the fuel cell after oxygen is supplied to the fuel cell based on the preset condition;
in a first voltage state where the detected open circuit voltage is higher than the target voltage by a first value or larger, reducing an amount of oxygen supplied to the fuel cell;
in a second voltage state where the detected open circuit voltage is lower than the target voltage by a second value or larger, increasing the amount of oxygen supplied to the fuel cell; and
in a voltage keeping state where the detected open circuit voltage is lower than a sum of the target voltage and the first value and higher than a value obtained by subtracting the second value from the target voltage, keeping the amount of oxygen supplied to the fuel cell.
1 Assignment
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Accused Products
Abstract
A voltage control method for a fuel cell may include: interrupting electrical connection between the fuel cell and a load in a low load state; supplying oxygen to the fuel cell in accordance with a preset condition during the electrical connection is interrupted; detecting an OCV of the fuel cell after oxygen is supplied to the fuel cell in accordance with the preset condition; reducing an amount of oxygen supplied to the fuel cell when the OCV is higher than a target voltage by a first value or larger; increasing the amount of oxygen when the OCV is lower than the target voltage by a second value or larger; and keeping the amount of oxygen when the OCV is lower than a sum of the target voltage and the first value and higher than a value obtained by subtracting the second value from the target voltage.
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Citations
13 Claims
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1. A voltage control method for a fuel cell in a power supply system including the fuel cell configured to supply an electric power to a load, the voltage control method comprising:
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interrupting an electrical connection between the fuel cell and the load when the load is in a low load state where the electric power required by the load is less than or equal to a predetermined reference value; supplying oxygen to the fuel cell based on a preset condition when the electrical connection between the fuel cell and the load is interrupted, the preset condition being a condition for supplying the fuel cell with oxygen required to adjust an open circuit voltage of the fuel cell to a predetermined target voltage; detecting the open circuit voltage of the fuel cell after oxygen is supplied to the fuel cell based on the preset condition; in a first voltage state where the detected open circuit voltage is higher than the target voltage by a first value or larger, reducing an amount of oxygen supplied to the fuel cell; in a second voltage state where the detected open circuit voltage is lower than the target voltage by a second value or larger, increasing the amount of oxygen supplied to the fuel cell; and in a voltage keeping state where the detected open circuit voltage is lower than a sum of the target voltage and the first value and higher than a value obtained by subtracting the second value from the target voltage, keeping the amount of oxygen supplied to the fuel cell. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A voltage control method for a fuel cell in a power supply system including the fuel cell configured to supply an electric power to a load, the voltage control method comprising:
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supplying oxygen to the fuel cell based on a preset condition in a low load state where an electric power required by the load is less than or equal to a predetermined reference value, the preset condition being a condition for supplying the fuel cell with oxygen required to adjust a voltage of the fuel cell to a predetermined target voltage; detecting the voltage of the fuel cell after oxygen is supplied to the fuel cell based on the preset condition; causing the fuel cell to generate an electric power by setting an output voltage to the target voltage in a first voltage state where the detected voltage is higher than the target voltage by a first value or larger; in a second voltage state where the detected voltage is lower than the target voltage by a second value or larger, increasing an amount of oxygen supplied to the fuel cell in a state where electrical connection between the fuel cell and the load is interrupted; and keeping the amount of oxygen supplied to the fuel cell in a voltage keeping state where the detected voltage is lower than a sum of the target voltage and the first value and is higher than a value obtained by subtracting the second value from the target voltage.
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10. A power supply system comprising:
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a fuel cell configured to supply an electric power to a load; an oxygen supply device configured to supply oxygen to a cathode of the fuel cell; an oxygen amount regulator configured to regulate an amount of oxygen supplied to the cathode by the oxygen supply device; a load interrupter configured to interrupt electrical connection between the fuel cell and the load in a low load state where an electric power required by the load is lower than or equal to a predetermined reference value; and a voltage sensor configured to detect an open circuit voltage of the fuel cell, wherein the oxygen amount regulator is further configured to drive the oxygen supply device in accordance with a preset condition in the low load state, the preset condition being a condition for supplying the fuel cell with oxygen required to adjust the open circuit voltage of the fuel cell to a predetermined target voltage, the oxygen amount regulator is further configured to drive, after the oxygen supply device is driven, the oxygen supply device in a first voltage state to decrease the amount of oxygen supplied to the fuel cell, the first voltage state being a state where the detected open circuit voltage is higher than the target voltage by a first value or larger, and the oxygen amount regulator is further configured to drive, after the oxygen supply device is driven, the oxygen supply device in a second voltage state to increase the amount of oxygen supplied to the fuel cell, the second voltage state being a state where the detected open circuit voltage is lower than the target voltage by a second value or larger. - View Dependent Claims (11, 12)
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13. A power supply system comprising:
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a fuel cell configured to supply an electric power to a load; an oxygen supply device configured to supply oxygen to a cathode of the fuel cell; at least one electronic control unit configured to adjust an amount of oxygen supplied by the oxygen supply device to the cathode and to control a state of output of the fuel cell; a load interrupter configured to interrupt electrical connection between the fuel cell and the load; and a voltage sensor configured to detect a voltage of the fuel cell, wherein the electronic control unit is further configured to drive the oxygen supply device in accordance with a preset condition in a low load state, the preset condition being a condition for supplying the fuel cell with oxygen required to adjust the voltage of the fuel cell to a predetermined target voltage, the electronic control unit is further configured to drive the oxygen supply device to increase the amount of oxygen, which is supplied to the cathode, after the oxygen supply device is driven in accordance with the preset condition, in a second voltage state, and in a state where the load interrupter interrupts the electrical connection between the fuel cell and the load, the second voltage state being a state where the detected voltage is lower than the target voltage by a second value or larger, and the electronic control unit is configured to control the state of output of the fuel cell to change an output voltage of the fuel cell to the target voltage after the electronic control unit drives the oxygen supply device in accordance with the preset condition, and in a first voltage state where the detected voltage is higher than the target voltage by a first value or larger.
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Specification