Abstract: A current detection circuit and a transformer current measurement system are offered, in which when elements and circuit, which cannot operate originally unless a transformer with small excitation inductance is used, are connected to a primary side of the transformer, even if the transformer, whose excitation inductance is large, is used, transformer current (primary current and secondary current) can be measured without deteriorating operations of the elements and circuit. [Means for solving] A current detector CT (current transformer) is in series connected to a primary winding 111 of a transformer 11, and an inductor La is in parallel connected to to a series connection of the current detector CT and the primary winding 111. And, secondary current I2 of the transformer 11 is measured based on a value of primary current IT detected by the current detector CT.

Abstract: A current detection circuit and a transformer current measurement system are offered, in which when elements and circuit, which cannot operate originally unless a transformer with small excitation inductance is used, are connected to a primary side of the transformer, even if the transformer, whose excitation inductance is large, is used, transformer current (primary current and secondary current) can be measured without deteriorating operations of the elements and circuit. [Means for solving] A current detector CT (current transformer) is in series connected to a primary winding 111 of a transformer 11, and an inductor La is in parallel connected to to a series connection of the current detector CT and the primary winding 111. And, secondary current I2 of the transformer 11 is measured based on a value of primary current IT detected by the current detector CT.

Abstract: In a DC-DC converter using, as an input source, a fuel cell, a solar cell, or the like, having a relatively large output impedance in a power-supply mode, an arbitrary load and secondary battery based on magnetic coupling in which voltage values are determined by a turns ratio between those wound around a winding, are provided as outputs, a second converter is connected between an output of the secondary battery and the load. In addition, a current control circuit connected to the secondary battery is configured to perform control so that, when a current in the load decreases due to an operation of the magnetic coupling, by increasing a charging current which flows into the secondary battery, and, when the current in the load increases, by decreasing the charging current to the secondary battery, an output voltage of the secondary battery is maintained at a set drooping voltage.

Abstract: The present invention provides a fuel cell optimum operating point tracking system capable of ensuring optimum operation of a fuel cell, by detecting the optimum operation voltage of the fuel cell taking not only temperature dependence of the output characteristics thereof, but also chemical reactions into consideration.

Abstract: A new charger wherein a reference voltage can be set therein. The charger charges a secondary battery via a DC/DC converter that has an arrangement in which a fuel cell, a solar cell or the like having a relatively large output impedance during power supply is used as an input source (Vfc) and an input power is kept constant. The secondary battery (B) is connected to a control circuit (10), and a constant power reference voltage control circuit (20) is connected between the current control circuit and an input of the charger. When the output of the charger is drooping, the constant power reference voltage control circuit reduces the reference voltage to increase the power to be supplied, thereby providing a constant power at the voltage as defined by the output voltage stabilization control of the charger. When the input power of the charger is excessive, the constant power reference voltage control circuit increases the reference voltage to set a reference value corresponding to the power to be supplied.

Abstract: The present invention provides a novel DC-DC converter in which, by achieving constant power control that sets power supply on an output side to be equal to supply power of a fuel cell on an input side, a cell charging current is set to be constant, components are reduced, and stable charging is performed. In a DC-DC converter using, as an input source (Vfc), a fuel cell, a solar cell, or the like, having a relatively large output impedance in a power-supply mode, an arbitrary load (Ro) and secondary battery (B), based on magnetic coupling in which voltage values are determined by a turns ratio between those wound around a winding, are provided as outputs, a second converter (30) is connected between an output of the secondary battery and the load.

Abstract: A novel charger wherein a constant electric power control is made such that an electric power feed at the output end is the same as the electric power fed by a fuel cell at the input end, thereby keeping a cell charge current constant, reducing the number of components and further realizing a stable charging. A charger, an input source (Vfc) of which is a fuel cell or solar cell exhibiting a relatively large output impedance during electric power feed, includes a secondary cell (B) at the output end. A current control circuit (10), which is connected to the secondary cell, supplies a charging current to be caused to flow into the secondary cell. The value of the charging current is obtained from a control amount necessary for maintaining a converter output voltage at a drooping voltage as set.

Abstract: A new charger wherein a reference voltage can be set therein. The charger charges a secondary battery via a DC/DC converter that has an arrangement in which a fuel cell, a solar cell or the like having a relatively large output impedance during power supply is used as an input source (Vfc) and an input power is kept constant. The secondary battery (B) is connected to a control circuit (10), and a constant power reference voltage control circuit (20) is connected between the current control circuit and an input of the charger. When the output of the charger is drooping, the constant power reference voltage control circuit reduces the reference voltage to increase the power to be supplied, thereby providing a constant power at the voltage as defined by the output voltage stabilization control of the charger. When the input power of the charger is excessive, the constant power reference voltage control circuit increases the reference voltage to set a reference value corresponding to the power to be supplied.

Abstract: The invention provides a charger capable of keeping a charging current flowing through a cell constant, of reducing the number of components, and of realizing stable charging by controlling supply power on the output side thereof to be equal to supply power on the input side of a fuel cell. A charger has an output end connected to a secondary cell (B) and uses, as an input source (Vfc), a cell having relatively large output impedance when electric power is supplied, such as a fuel cell or a solar cell. The charger includes a current control circuit (10) which is connected to the secondary cell and supplies a charging current flowing into the secondary cell as a current value which is obtained from a control value necessary for keeping an output voltage of a converter at a dropping voltage to be set.

Abstract: The present invention provides a fuel cell optimum operating point tracking system capable of ensuring optimum operation of a fuel cell, by detecting the optimum operation voltage of the fuel cell taking not only temperature dependence of the output characteristics thereof, but also chemical reactions into consideration.