Fuel cell system
First Claim
1. A fuel cell system comprising:
- a drive motor serving as a power source for driving a load and driven by electric power;
a fuel cell generating electricity with electrochemical reaction of an oxidation gas containing oxygen to a fuel gas containing hydrogen and supplying the electric power to said drive motor;
a first boost device boosting a voltage output from said fuel cell and enabling the post-boosting voltage to be supplied to said drive motor;
a secondary battery capable of charging and discharging of the electric power and supplying the electric power to said drive motor with the discharge;
a second boost device boosting a voltage output from said secondary battery and enabling the post-boosting voltage to be supplied to said drive motor; and
a boost control unit controlling the voltage boost by said first boost device on the basis of a correlation between an output voltage of said fuel cell and a motor voltage necessary for driving said drive motor,wherein said boost control unit calculates output electric power of said fuel cell when driving said drive motor on the basis of the electric power supplied to the drive motor necessary for driving said drive motor, the electric power in the charge and the discharge of said secondary battery, the electric power that is lost when said first boost device boosts the output voltage of said fuel cell and the electric power that is lost when said second boost device boosts the output voltage of said secondary battery, and calculates output voltage of said fuel cell from the calculated output electric power of said fuel cell, andwherein said boost control unit conducts a control of the voltage boost by said first boost device, which is as to whether said drive motor is driven by the output voltage of said fuel cell or by a post-boosting voltage given after boosting said output of said fuel cell, based on a result of comparison between said output voltage of said fuel cell and the motor voltage necessary for driving said drive motor, andwherein said boost control unit, when the output voltage of said fuel cell is higher than the motor voltage of said drive motor, inhibits the output voltage of said fuel cell from being boosted by said first boost device and thus supplies the output voltage of said fuel cell directly to said drive motor, andwherein said boost control unit, when the output voltage of said fuel cell is not higher than the motor voltage of said drive motor, supplies the post-boosting voltage given after boosting said output voltage of said fuel cell by the first boost device to said drive motor.
1 Assignment
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Accused Products
Abstract
In order to assure drive of a drive motor, a boost operation of a boost device is appropriately performed by judging whether a voltage supplied from a fuel cell suffices a voltage required for driving the drive motor, thereby suppressing a switching loss by the boost device. A fuel cell system is a power source for driving a load. The system includes: a drive motor driven by an electric power; a fuel cell which generates electricity by an electrochemical reaction between an oxidizing gas containing oxygen and a fuel gas containing hydrogen and supplies an electric power to the drive motor; a first boost device which can boosts the voltage outputted from the fuel cell and supplies the boosted voltage to the drive motor; and boost control means which controls voltage boost performed by the first boost device according to the relationship between the fuel cell output voltage and the voltage required by the drive motor.
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Citations
15 Claims
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1. A fuel cell system comprising:
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a drive motor serving as a power source for driving a load and driven by electric power; a fuel cell generating electricity with electrochemical reaction of an oxidation gas containing oxygen to a fuel gas containing hydrogen and supplying the electric power to said drive motor; a first boost device boosting a voltage output from said fuel cell and enabling the post-boosting voltage to be supplied to said drive motor; a secondary battery capable of charging and discharging of the electric power and supplying the electric power to said drive motor with the discharge; a second boost device boosting a voltage output from said secondary battery and enabling the post-boosting voltage to be supplied to said drive motor; and a boost control unit controlling the voltage boost by said first boost device on the basis of a correlation between an output voltage of said fuel cell and a motor voltage necessary for driving said drive motor, wherein said boost control unit calculates output electric power of said fuel cell when driving said drive motor on the basis of the electric power supplied to the drive motor necessary for driving said drive motor, the electric power in the charge and the discharge of said secondary battery, the electric power that is lost when said first boost device boosts the output voltage of said fuel cell and the electric power that is lost when said second boost device boosts the output voltage of said secondary battery, and calculates output voltage of said fuel cell from the calculated output electric power of said fuel cell, and wherein said boost control unit conducts a control of the voltage boost by said first boost device, which is as to whether said drive motor is driven by the output voltage of said fuel cell or by a post-boosting voltage given after boosting said output of said fuel cell, based on a result of comparison between said output voltage of said fuel cell and the motor voltage necessary for driving said drive motor, and wherein said boost control unit, when the output voltage of said fuel cell is higher than the motor voltage of said drive motor, inhibits the output voltage of said fuel cell from being boosted by said first boost device and thus supplies the output voltage of said fuel cell directly to said drive motor, and wherein said boost control unit, when the output voltage of said fuel cell is not higher than the motor voltage of said drive motor, supplies the post-boosting voltage given after boosting said output voltage of said fuel cell by the first boost device to said drive motor. - View Dependent Claims (2, 3)
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4. A fuel cell system comprising:
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a drive motor serving as a power source for driving a load and driven by electric power; a fuel cell generating electricity with electrochemical reaction of an oxidation gas containing oxygen to a fuel gas containing hydrogen and supplying the electric power to said drive motor; a first boost device boosting a voltage output from said fuel cell and enabling the post-boosting voltage to be supplied to said drive motor; a secondary battery capable of charging and discharging of the electric power and supplying the electric power to said drive motor with the discharge; a buck-boost device stepping up and down a voltage output from said secondary battery and enabling the post-stepping-up-and-down voltage to be supplied to said drive motor; and a boost control unit controlling the voltage boost by said first boost device on the basis of a correlation between an output voltage of said fuel cell and a motor voltage necessary for driving said drive motor, wherein said boost control unit calculates output electric power of said fuel cell when driving said drive motor on the basis of the electric power supplied to the drive motor necessary for driving said drive motor, the electric power in the charge and the discharge of said secondary battery, the electric power that is lost when said first boost device boosts the output voltage of said fuel cell and the electric power that is lost when said buck-boost device steps up and down the output voltage of said secondary battery, and calculates output voltage of said fuel cell from the calculated output electric power of said fuel cell, and wherein said boost control unit conducts a control of the voltage boost by said first boost, which is as to whether said drive motor is driven by the output voltage of said fuel cell or by a post-boosting voltage given after boosting said output voltage of said fuel cell, based on a result of comparison between said output voltage of said fuel cell and the motor voltage necessary for driving said drive motor, and wherein said boost control unit, when the output voltage of said fuel cell is higher than the motor voltage of said drive motor, inhibits the output voltage of said fuel cell from being boosted by said first boost device and thus supplies the output voltage of said fuel cell directly to said drive motor, and wherein said boost control unit, when the output voltage of said fuel cell is not higher than the motor voltage of said drive motor, supplies the post-boosting voltage given after boosting said output voltage of said fuel cell by the first boost device to said drive motor. - View Dependent Claims (5, 6)
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7. A fuel cell system comprising:
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a drive motor serving as a power source for driving a load and driven by electric power; a fuel cell generating electricity with electrochemical reaction of an oxidation gas containing oxygen to a fuel gas containing hydrogen and supplying the electric power to said drive motor, an output voltage of said fuel cell being set so as to exceed a motor voltage necessary for driving said drive motor in a predetermined drive range defined as a partial area of all a drive range that can be taken by said drive motor, the predetermined drive range being the range in which a frequency of the user'"'"'s request for driving the load is equal to or larger than a predetermined rate; a first boost device boosting a voltage output from said fuel cell and enabling the post-boosting voltage to be supplied to said drive motor, the first boost device being able to control a terminal voltage of the fuel cell through the boost operation thereof; and a boost control unit intermittently controlling the voltage boost by said first boost device on the basis of a correlation between an output voltage of said fuel cell and the motor voltage necessary for driving said drive motor when driving said drive motor, wherein said boost control unit, when a drive state of said drive motor belongs to the predetermined drive range, restricts the output voltage of said fuel cell from being boosted by said first boost device and thus supplies the output voltage of said fuel cell directly to said drive motor. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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15. A fuel cell system comprising:
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a drive motor serving as a power source for driving a load and driven by electric power; a fuel cell generating electricity with electrochemical reaction of an oxidation gas containing oxygen to a fuel gas containing hydrogen and supplying the electric power to said drive motor, an output voltage of said fuel cell being set so as to exceed a motor voltage necessary for driving said drive motor in a predetermined drive range defined as a partial area of all a drive range that can be taken by said drive motor, the predetermined drive range being the range in which a frequency of a user'"'"'s request for driving the load is equal to or larger than a predetermined rate; a first boost device boosting a voltage output from said fuel cell and enabling the post-boosting voltage to be supplied to said drive motor, the first boost device being able to control a terminal voltage of the fuel cell through the boost operation thereof; and a boost control unit intermittently controlling the voltage boost by said first boost device on the basis of a correlation between an output voltage of said fuel cell and the motor voltage necessary for driving said drive motor when driving said drive motor, wherein said boost control unit, when an input-side voltage of said first boost device in said fuel cell system is higher than the motor voltage, restricts the output voltage of said fuel cell from being boosted by said first boost device and thus supplies the output voltage of said fuel cell directly to said drive motor.
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Specification