Abstract: There is disclosed a converter controller which can simply and early detect an abnormality of an auxiliary circuit constituting a soft switching converter. On turning off a first switching element, a controller detects a voltage between both the ends of a snubber capacitor and a voltage between both the ends of the first switching element, to obtain a difference voltage. The controller compares the obtained difference voltage with a voltage threshold value stored in a memory (not shown) to judge whether or not the difference voltage is larger than the voltage threshold value. When the difference voltage is smaller than the voltage threshold value, the controller judges that an auxiliary circuit is normal, to end processing, whereas when the difference voltage is not less than the voltage threshold value, the controller judges that a failure (an open failure) occurs in the auxiliary circuit, to shift to a fail safe operation, thereby ending the processing.

Abstract: A fuel cell system capable of reducing time spent before actual execution of low-temperature countermeasure processing is provided. At the time of activation, a control unit for the fuel cell system refers to, for example, a detected FC temperature and judges whether or not the low-temperature countermeasure processing is necessary for the activation. If the control unit determines that the low-temperature countermeasure processing is necessary, it controls an output voltage of the fuel cell to be a target voltage for the low-temperature countermeasure processing, without having the fuel cell enter an OCV state, and then executes the low-temperature countermeasure processing.

Abstract: A driving frequency setting portion is provided. The driving frequency setting portion sets a switching frequency of a switching element on the basis of a notification from a driving phase number switching portion. A ripple current detected by a current sensor is in inverse proportion to inductance of reactor. Since a ripple current becomes the largest in the single-phase driving, in this embodiment, considering both the ripple current and switching loss, a switching frequency for the single-phase driving is set higher than a switching frequency for multiphase driving.

Abstract: Provided is a converter control device which detects an on-failure of an auxiliary switch constituting an auxiliary circuit of a soft switching converter and can prevent element failures. A current sensor for detecting the current flowing in a coil is provided between a fuel cell and the. A controller sequentially detects current by use of the current sensor and makes a judgment as to whether or not the detected has exceeded an overcurrent threshold value stored in a memory (not shown). When the controller judges that the current has exceeded the overcurrent threshold value, the controller judges that a second switching element has an on-failure, and performs a fail-safe operation by stopping the driving of a converter (for example, a U-phase converter) of an auxiliary circuit provided with this second switching element.

Abstract: A converter control device includes a converter device formed by three converter circuits connected together in parallel between a secondary battery as a first power source and a fuel cell as a second power source. A control unit includes: a PID control module for controlling the converter device by PID control and executing a desired voltage conversion; a drive phase quantity changing module for changing the number of drive phases of the converter device in accordance with the passing power of the converter device; and an integration term correction function switching module which switches the PID control integration term correction function when changing the number of drive phases.

Abstract: There is provided a fuel cell system capable of warming up a fuel cell while inhibiting generation of a rush current. A control device switches the connection/disconnection between a fuel cell and a short circuit by a shorting relay. The control device spends, before switching the shorting relay from disconnection to connection during starting at a low temperature, an oxidizing gas remaining in the cathode of the fuel cell by driving auxiliary devices to generate an oxidizing gas-deficient state. Then, the control device switches FC relays from ON to OFF and the shorting relay from OFF to ON to thereby complete the preparation for supplying a short-circuit current.

Abstract: A converter device which is configured by connecting three converter circuits in parallel is provided between a secondary battery serving as a first power supply and a fuel cell serving as a second power supply. Two differential ammeters are placed on three reactors corresponding to the three converter circuits. A control unit includes a passing electric power calculation module which calculates electric power passing through the converter device on the basis of detected values of the two differential ammeters, an electric power equalization module which performs equalization of passing electric power between the respective converter circuits which constitute the converter device, a module for changing the number of drive phases which changes the number of drive phases of the converter device in response to the passing electric power, and a voltage conversion control module which controls the converter device and executes a desired voltage conversion.

Abstract: Provided is a converter controller capable of preventing destruction of an element such as an auxiliary switch by preventing operation interference between auxiliary circuits of respective phases in a multiphase soft switching converter. A duty threshold input unit receives, as an input, an obtained acceptable duty deviation value. A duty deviation computation unit judges whether or not the duty deviation between the phases does not exceed an acceptable duty deviation value. When the duty deviation between the phases exceeds the acceptable duty deviation value, the duty deviation computation unit corrects an adjusted U-phase duty ratio, adjusted V-phase duty ratio and adjusted W-phase duty ratio under the PID control rule, and outputs the resultant duty ratios to an FC converter control circuit.

Abstract: The present invention detects a failure in an FC converter. A target voltage determination section determines an output target voltage for a fuel cell. A superimposition signal generation section generates a predetermined reference signal to be superimposed onto the output target voltage. A voltage command signal generation section generates a voltage command signal by superimposing the reference signal onto the output target voltage. A frequency characteristics calculation section calculates the frequency characteristics of the reference signal component superimposed on the output voltage of the fuel cell. A failure judgment section judges that a failure occurs in the FC converter if a value of the calculated frequency characteristics is less than the lower limit threshold value of an allowable range established based on reference characteristics.

Abstract: When a power generation instruction value for a fuel cell is reduced during warm-up of the fuel cell by a low power generation efficiency operation as compared to a normal operation and when supply of a reactant gas to the fuel cell cannot be controlled so as to follow the reduction of the power generation instruction value, the reactant gas supply to the fuel cell is reduced and the output voltage to the fuel cell is increased. Thus, it is possible to charge an excessive power equivalent to a difference between a fuel cell generation amount and the power generation instruction value into a capacitance component of the fuel cell, so that the power supplied to the external load of the fuel cell coincides with the power generation instruction value. Thus, when a power request for the fuel cell during the low-efficiency operation is suddenly reduced, it is possible to perform control so that the excessive power is not supplied to the external load.

Abstract: There is provided a fuel cell system in which a constantly accurate impedance measurement is made possible regardless of a response characteristic of the voltage converting device. A superimposed signal analysis section analyzes an impedance measuring signal after passing through a DC/DC converter to thereby notify a superimposed signal amplitude control section of an analysis result. A superimposed signal amplitude control section controls an amplitude value of the impedance measuring signal generated by a superimposed signal generating section based on the result notified from the superimposed signal analysis section.

Abstract: A fuel cell system includes: a fuel cell stack which receives a fuel gas and an oxidation gas to generate a power; an air compressor which supplies the oxidation gas to the fuel cell stack; and a controller which reduces the oxidation gas flow rate supplied from the air compressor to the fuel cell stack in consideration of discharge from a capacitance component of the fuel cell stack when decreasing the output voltage of the fuel cell stack. When the output voltage of the fuel cell stack has dropped, the fuel cell system can control a cell operation in consideration of the discharge from the capacitance component of the fuel cell stack to an external load.

Abstract: A multi-phase voltage converting device includes voltage converters each performing voltage conversion based on a control period selected from among a plurality of predetermined control periods, and a control device indicating the control period to the voltage converters. The control device updates the control period of voltage converters in a predetermined period related commonly to the plurality of control periods. The update period is a least common multiple of the plurality of control periods. The plurality of voltage converters are n in number, and the control device successively updates the control periods for the plurality of voltage converters with a time difference equal to 1/n of the update period. Thereby, the multi-phase voltage converting device suppressing output voltage ripples can be provided.

Abstract: There is disclosed a fuel cell system or the like capable of sufficiently reducing an exhaust hydrogen concentration even in a case where a fuel cell is operated in a state of a low power generation efficiency. A bypass valve B1 is arranged between an oxidation gas supply path 11 and a cathode-off gas channel 12. In a state in which supply of an oxidation gas to a cathode falls short, pumping hydrogen is included in a cathode-off gas. Therefore, a valve open degree of the bypass valve B1 is regulated, and a flow rate of bypass air is regulated to control the exhaust hydrogen concentration.

Abstract: A fuel cell system according to the present invention is characterized by comprising a fuel cell, measurement means for measuring impedances of the fuel cell in two kinds or more of frequency regions, and first judgment means for judging two or more parameters concerned with an internal state of the fuel cell based on measurement results of the impedances in the respective frequency regions. According to such a constitution, the impedances in the two or more types of frequency regions (a high frequency region, a low frequency region and the like) are measured to judge two or more parameters such as a wet state of an electrolytic film of the fuel cell and a supply state of a fuel gas, which are concerned with the internal state of the fuel cell based on this measurement result. Since such judgment is performed, as compared with the conventional technology, the internal state of the fuel cell can accurately be grasped, and highly efficient and highly robust control of the fuel cell system can be performed.

Abstract: There is disclosed a fuel cell system capable of stably operating auxiliary devices driven at a high voltage and the like, even in a case where a poisoned electrode catalyst is recovered or a fuel cell is warmed up. On detecting that the electrode catalyst is poisoned, a controller derives a target operation point which is sufficient for recovering an activity of the poisoned electrode catalyst. Then, shift of the operation point from a usual operation point to a low-efficiency operation point is realized so that an output power is held to be constant.

Abstract: An object is to miniaturize booster coils used in a vehicle-mounted booster converter. In the design method for a vehicle-mounted multi-phase converter including multiple booster coils and a switching circuit for generating an induced electromotive force at each booster coil by switching of current flowing to each booster coil for applying an output voltage, based on an input voltage and the induced electromotive force generated at each booster coil, to a vehicle drive circuit, a coupling factor indicating the extent by which the induced electromotive force in one of multiple booster coils contributes to the voltage between terminals of another booster coil is determined on the basis of a relationship between the coupling factor and current ripple component of each booster coil.

Abstract: Even in a case where a rapid variance is demanded as to the input voltage of a converter and the output terminal voltage of a fuel cell, stable converter control is realized. On judging that the change ratio of the demand power of a fuel cell exceeds a set threshold value, a controller executes converter stabilization processing. First, the controller controls a battery converter so that an input voltage of an inverter becomes a set target input voltage. Then, after the input voltage of the inverter reaches the target input voltage, the controller controls an FC converter so that an output terminal voltage of the fuel cell becomes a set target output terminal voltage.

Abstract: There is disclosed a fuel cell system which can control an output current of a fuel cell even if an error occurs in split flow control of an oxidizing gas. The fuel cell system includes a fuel cell and a feed device for supplying the oxidizing gas under pressure to the fuel cell. A feed channel is connected to a discharge channel by a bypass channel so that the oxidizing gas flows while bypassing the fuel cell. The system includes a regulator valve and a bypass valve which adjust the split flow of the oxidizing gas to the bypass channel and the fuel cell. When the regulator valve or the bypass valve has an error, a controller stops the control of the output current of the fuel cell by control of the regulator valve and switches the control to a control of the output current of the fuel cell by control of the feed device.

Abstract: A fuel cell system is equipped with a drive motor, a fuel cell, normal electric power generation means for performing normal electric power generation under a condition that the fuel cell is not warmed up, warm-up electric power generation means for performing warm-up electric power generation with lower electric power generation efficiency than normal electric power generation, and warm-up control means for controlling performance of warm-up electric power generation by the warm-up electric power generation means on a basis of a predetermined index on a necessity to warm up the fuel cell. The warm-up control means controls an operation state of the fuel cell during warm-up electric power generation on a basis of a correlation between the system loss required for warm-up of the fuel cell and a warm-up output required for driving of a load including the drive motor during warm-up of the fuel cell.