Abstract: Provided is a fuel cell system capable of accurately estimating I-V characteristics of a fuel cell. An impedance measurement section measures an impedance of the fuel cell and obtains a voltage drop caused by a direct-current resistance. An air stoichiometry judgment section detects the amount of oxidant gas supplied to the fuel cell and thereby judges whether or not the air stoichiometry ratio is 1 or higher at this time point. An estimated I-V characteristics line creation section determines that the remaining voltage component consists entirely of an activation voltage when the air stoichiometry ratio notified by the air stoichiometry judgment section is 1 or higher, while determining that the remaining voltage drop component includes the combination of the activation overvoltage and voltage drop corresponding to the change in the electromotive voltage when the notified air stoichiometry ratio is below 1.

Abstract: A fuel cell system is equipped with a drive motor, a fuel cell, and a controller. The controller performs normal electric power generation under a condition that the fuel cell is not warmed up, warm-up electric power generation with lower electric power generation efficiency than normal electric power generation, and controls performance of warm-up electric power generation on a basis of a predetermined index on a necessity to warm up the fuel cell. The controller 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.

Abstract: A fuel cell system increases an output voltage of a fuel cell if an electric power generation command value Pref for the fuel cell abruptly reduces while the fuel cell is being warmed up at a low-efficiency operation, which has lower electric power generation efficiency than that of a normal operation. Thus, the surplus electric power Ws corresponding to the difference between an electric power generation amount Pmes of the fuel cell and the electric power generation command value Pref is stored into a capacitive component of the fuel cell, thereby matching the electric power supplied to an external load of the fuel cell (Pmes-Ws) with the electric power generation command value Pref. This makes it possible to conduct control not to supply the surplus electric power to the external load when the electric power required from the fuel cell suddenly reduces during the low-efficiency operation.

Abstract: A fuel cell system is configured to have: a voltage superimposing unit that superimposes a predetermined AC signal on an output voltage of a fuel cell; a unit that detects an output voltage value of a battery device, the output voltage value varying as the fuel cell output voltage value on which the AC signal has been superimposed varies; a battery device voltage comparison unit that compares the detected battery device output voltage value with a predetermined threshold voltage; and a measurement permission determination unit that determines whether the AC impedance measurement is permitted or not based on whether or not the battery device output voltage value exceeds the threshold voltage. The fuel cell system can protect the battery device in the impedance measurement of the fuel cell based on an AC impedance method.

Abstract: A voltage conversion circuit apparatus that adjusts a timing skew between the switching control of the first switching element and the switching control of the second switching element includes: a skew storage portion that stores a timing skew between the switching controls of the first and second switching elements after the voltage conversion circuit apparatus is manufactured; and a timing adjustment portion that corrects the stored timing skew and thereby adjusts the timing relation between a first pulse signal and a second pulse signal so as to bring within a permissible range the timing skew that occurs when the switching controls of the first and second switching elements are performed by using the first pulse signal and the second pulse signal.

Abstract: An object is to miniaturize device size in a vehicle mounted converter. The vehicle mounted converter includes a plurality of inductors, a switching unit for switching current path, an external power acquisition unit for acquiring alternating current power from a power generation source provided separately from the mounted vehicle, and a switching means for switching a circuit connection state to a connection state of either a boost connection state for connecting one end of the inductors to a path to a battery for vehicle drive power supply and connecting the switching unit to the other end of the inductors, or a charging connection state for connecting one end of one of the plurality of inductors to the path to the battery, disconnecting one end of the remaining inductors from the path to the battery and connecting to the external power acquisition unit, and connecting the other end of the inductors to the switching unit.

Abstract: A fuel cell system capable of improving the voltage controllability of a converter provided in the system is provided. A controller judges whether or not a passing power of a DC/DC converter falls within a reduced response performance area for the number of active phases as of the present moment. When the controller determines that the passing power of the DC/DC converter falls within the reduced response performance area, the controller determines the number of phases which avoids the driving within the reduced response performance area, and outputs a command for switching to the determined number of phases (phase switching command) to the DC/DC converter.

Abstract: Disclosed is a fuel cell system including a fuel cell which generates a power, and control means for decreasing the amount of a reactant gas to be supplied to the fuel cell to an amount smaller than that during normal power generation to realize low-efficiency power generation of the fuel cell. The control means sets the voltage lower limit value of the fuel cell so that the amount of an anode gas (pumping hydrogen) to be formed in a cathode of the fuel cell during the low-efficiency power generation is a predetermined amount or less.

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: A chopper circuit includes an input unit that inputs a main turn-on signal for turning on a main switching element and an auxiliary turn-on signal for turning on an auxiliary switching element; and a prohibiting unit that prohibits the main switching element from turning on unless the auxiliary turn-on signal is input.

Abstract: An FC voltage increasing converter includes a plurality of converter parts having reactors. Regarding the first of the plurality of converter parts provided with a thermistor, the output starts to be limited when the temperature detected by the thermistor reaches a limitation starting temperature, which is obtained based on a reference heat-resistant temperature, which is obtained by subtracting an error of the thermistor from a specification heat-resistant temperature of each of the reactors. Meanwhile, regarding the second, third and fourth of the plurality of converter parts not provided with thermistors, the outputs start to be limited when the temperature detected by the thermistor reaches a limitation starting temperature obtained based on an allowable temperature, which is obtained by subtracting a characteristic-variation temperature of the reactor from the reference heat-resistant temperature of the reactor.

Abstract: A voltage boost converter includes: a main voltage boost portion that has a first switch and a first coil, and that raises output voltage of a direct-current power source by using counter electromotive force of the coil caused by the switch performing a switching action on the coil; and a subsidiary voltage boost portion which has a capacitor that adjusts potential difference between two poles of the switch by amount of electricity stored, and which reduces switching loss of the switch by adjusting the amount of electricity in the capacitor during the switching action, and which has a second switch and a second coil. The second coil is formed by winding a wire around at least a portion of a core formed of a magnetic body. The core is provided with a gap formed of a non-magnetic body. A core region formed of a magnetic body is adjacent to the gap.

Abstract: There is disclosed a fuel cell system or the like capable of stably operating an auxiliary machine and the like, even when recovering a poisoned electrode catalyst and warming up a fuel cell. A controller derives a target operation point sufficient for recovering activity of the poisoned electrode catalyst, and realizes shift of an operation point to a target operation point in a state in which an output power is held to be constant. The operation is switched to a low-efficiency operation point, whereby an output voltage of the fuel cell lowers, but the voltage is raised to an allowable input voltage of a high-voltage auxiliary machine by a DC/DC converter.

Abstract: There is disclosed a fuel cell system in which a poisoned electrode catalyst can be recovered while meeting a demand for an output power. When a controller detects that an electrode catalyst is poisoned, the controller derives a target operation point adequate for recovering a function of the poisoned electrode catalyst to realize shift of an operation point so that the output power is kept constant. Specifically, a fuel cell voltage is controlled using a DC/DC converter, and an amount of an oxidizing gas to be fed from an oxidizing gas supply source is adjusted, thereby controlling a fuel cell current.

Abstract: When the operation point of a DC/DC converter, which steps up/down the output voltage of a fuel cell stack, is in a range of reduction in response capability and further there is issued a request of determining an AC impedance, a controller switches numbers of the drive phases of the DC/DC converter to determine an AC impedance of the fuel cell stack. If the operation point of the DC/DC converter is in the range of reduction in response capability and further the precision of determining the AC impedance is reduced, then the determination of AC impedance in the range of reduction in response capability is inhibited and the switching of the phases of the DC/DC converter is implemented, thereby causing the operation point of the DC/DC converter to be out of the range of reduction in response capability, with the result that the precision of determining the AC impedance can be raised.

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 which generates electricity; and control means which supplies an output power from the fuel cell to a predetermined load power source while realizing a low-efficiency operation of the fuel cell, thereby driving and controlling the load power source. The control means sets the output voltage of the fuel cell during the low-efficiency operation to a value not smaller than the minimum drive voltage of the load power source.

Abstract: When a request power for a fuel cell is smaller than a predetermined value, a fuel cell system stops the supply of an oxidizing gas to the fuel cell and lowers the output voltage of the fuel cell from a use upper limit voltage to a reduction voltage to perform catalyst activation processing. When the output voltage of the fuel cell lowers to an air blow voltage because of the shortage of the oxidizing gas, the fuel cell system resupplies the oxidizing gas to recover the output voltage of the fuel cell.

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 control unit 80, when calculating a request current I0 according to a system request electric power Preq and calculating a target current I1 by correcting the request current I0 with PI compensation calculation based on a minimum cell voltage Vm detected by a cell monitor 101, variably changes a proportional gain Kp according to the current value at the present time when calculating a current limit value ?I as the amount of correction of a request current I0 according to the equation ?I=?V×Kp+??V×Ki, thereby enhancing controllability to control the current of a fuel cell 20 to a target current value I1. When controlling the current of a fuel cell by determining a target current value by correcting a request current by PI compensation using the difference between a minimum cell voltage and a threshold voltage, controllability to control the current of the fuel cell to the target current value can be enhanced.