Abstract: A fuel cell system comprises a fuel cell; a fuel cell controlling converter; an oxidizing gas supplier that is configured to supply an oxidizing gas to the fuel cell; and a controller that is configured to control a voltage and a current value of the fuel cell. In a first power generation state, the controller sets the voltage and the current value of the fuel cell according to a required output, based on a current-voltage characteristic of the fuel cell. In a second power generation state, the controller sets the voltage and the current value of the fuel cell according to the required output and a required amount of heat, to a voltage and a current value that provide a lower power generation efficiency than a power generation efficiency in the first power generation state. The controller reduces the required amount of heat in a process of changing over a power generation state from the second power generation state to the first power generation state.

Abstract: A fuel cell system comprising: a power generation controller that controls a value subject to control, which is a value exhibiting a power generating state by a fuel cell and is a value that is affected by alternating current applied to the fuel cell, to approach a target value; a dead zone setter that sets a dead zone with the target value as a reference; and, a stopper that stops the control by the power generation controller when the value subject to control is contained in the dead zone.

Abstract: The present invention enables the determination of an operating point of a fuel cell so as to prioritize the fulfillment of an amount of required power generation while avoiding various limitations, such as a current limit, in a fuel cell system that warms up the fuel cell by a low efficiency operation. A controller 70 multiplies a voltage command value Vcom obtained in step S3 by a current command value Icom obtained in step S1, then, this is divided by a final voltage command value Vfcom obtained in step S4, thereby obtaining a final current command value Ifcom to determine an operating point (Ifcom, Vfcom) during a warm-up operation (step S5), and then the process ends.

Abstract: An object is to provide a technique that suppresses excessive water drainage from a fuel cell. A water drainage device for fuel cell that drains water from inside of a fuel cell, includes: a purge gas supply system; an operation unit; a water drainage controller; and a water content acquirer. The operation unit receives a water drainage command from a user to give an instruction of purging out water from inside of the fuel cell by the purge gas supply system. When the water content obtained by the water content acquirer is equal to or lower than a predetermined value, the water drainage controller performs either one of: (i) a process of invalidating the water drainage command received by the operation unit; and (ii) a process of changing a processing condition of the purge process to decrease an amount of water drained by the purge process, compared with an amount of water drainage when the obtained water content is higher than the predetermined value.

Abstract: A fuel cell system includes: a fuel cell; a coolant path connected to the fuel cell and allowing a coolant that cools the fuel cell to flow therethrough; a temperature detection unit configured to detect a temperature of the coolant in the coolant path; a temperature correction unit configured to calculate a temperature correction value by correcting the temperature of the coolant detected by the temperature detection unit; and a lower limit voltage control unit configured to control a lower limit voltage of the fuel cell based on the temperature correction value, wherein the temperature correction unit calculates the temperature correction value based on a following equation: T filt = T filt ? _ ? old + T - T filt ? _ ? old ? where Tfilt represents the temperature correction value, Tfilt_old represents a last temperature correction value, T represents the temperature of the coolant, and ? represents a coefficient, and the coefficient when the temperature of the coolant is less than a

Abstract: The present invention provides a technique capable of satisfying both the restoration of an output voltage of a fuel cell and an improvement of electric power responsiveness in a fuel cell system in a situation in which its operation status is restored to a normal operation from an operation having low power generation efficiency. A controller updates a lower limit voltage threshold in accordance with the restoration of an FC voltage until the operation status is restored to a normal operation from an operation having low power generation efficiency, such as an intermittent operation and a warmup operation (step S1). The controller increases an FC current in accordance with the updated lower limit voltage threshold (steps S2 and S3) to thereby satisfy both the requirements of the restoration of the output voltage of the fuel cell stack and the improvement of the electric power responsiveness.

Abstract: A fuel cell system includes: a fuel cell outputting a current; a supply unit supplying oxidant gas; a flow-amount measurement unit measuring a flow amount of the oxidant gas; and a controller that feed-back controls the supply unit such that a measured flow-amount value converges toward a target flow-amount value, wherein the controller determines an acceptable current value in accordance with the measured flow-amount value, restricts the current to the acceptable current value or less, controls the current in accordance with a requested current value of the fuel cell; and performs a changing-suppression processing, when a condition continues for a predetermined period, the condition including that a changing width of the requested current value is equal to or less than a first value and a difference between the requested current value and the acceptable current value is equal to or less than a second value.

Abstract: A fuel cell system in which power generation is performed by a fuel cell, comprising: a power generation controller that performs: first control in which at least one of power control for preventing generated power from exceeding an upper limit value, voltage control for preventing generated voltage from falling below a lower limit value and current control for preventing generated current from exceeding an upper limit value is performed and second control in which the generated voltage is prevented from exceeding an upper limit value; and a priority instructor that instructs the power generation controller to prioritize the first control over the second control when the first control and the second control collide with each other.

Abstract: A fuel cell system includes: a converter disposed between a fuel cell and a load to increase an output voltage of the fuel cell; and a control unit that controls the converter at a predetermined duty ratio, wherein the control unit determines a duty command value for the converter from a feed-forward duty and a feed-back duty which are calculated using a command value of a reactor current that flows through a reactor in the converter and/or using a measurement value of the reactor current. In a low-load operation, the control unit sets, as a measurement value of the reactor current, a value obtained by multiplying a midpoint measurement value measured at an intermediate time of an on-duty period by a predetermined coefficient.

Abstract: A fuel cell system according to the present invention comprises: a fuel cell and a secondary battery, each acting as a power supply source; a first converter a second converter provided between the fuel cell and the secondary battery and first and second loads; a first inverter provided between the first and second converters and the first load and a second inverter provided between the first and second converters and the second load; a first controller that controls an output of the fuel cell by controlling the first converter; and a second controller configured separately from the first controller, the second controller controlling the second converter, the first inverter and the second inverter to thereby control outputs supplied to the first inverter and the second inverter, including an output from the secondary battery. The first and second controllers are connected so as to be able to communication with each other regarding failure information on respective control targets.

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: A fuel cell system comprising a fuel cell and a secondary cell as power supply sources to a load, in which, during normal operation, a first control part allows a first converter (boost converter at the fuel cell side) to control an output voltage of the fuel cell and a second control part allows a second converter (boost converter at the secondary cell side) to control an output voltage to a first load side, whereas during an occurrence of an abnormality of the secondary cell, the first control part allows the first converter to control an output voltage thereof and the second control part allows the second converter to control an output voltage to a second load side.

Abstract: The object of the present invention is to balance: the suppression of deterioration of a fuel cell and degradation of its durability and the optimization of the output control of the fuel cell. The present invention provides an output control apparatus for a fuel cell, being capable of switching a control mode between a power control mode in which an output power of a fuel cell connected to a load is controlled so as to be at a target power and a voltage control mode in which an output voltage of the fuel cell is controlled so as to be at a target voltage, wherein a control in the voltage control mode is performed when the output voltage of the fuel cell decreases below a predetermined low voltage threshold value.

Abstract: A manufacturing method for a chopper circuit that uses soft switching operation includes: identifying devices that constitute the chopper circuit and that are relevant to determining time at which a voltage applied to a main switching element during operation of the chopper circuit takes a minimum value; calculating a design representative value of an observed device that is at least one of the identified devices in such a manner that a plurality of the observed devices are prepared and then variations from a rated value in electrical characteristic of each observed device are subjected to statistical processing; and setting the representative value, instead of the rated value of the electrical characteristic of the observed device, in a switching control unit that controls the timings of switching of the main switching element and an auxiliary switching element on the basis of the electrical characteristics of the identified devices.

Abstract: In a fuel cell system which includes a high-electricity multiple-phase converter, noise generated due to an increase in reactor vibrations and due to a sound pressure increase caused by a plurality of reactors is effectively inhibited, and silence is improved. A fuel cell system includes a multiple-phase converter provided between a fuel cell and a load device. The fuel cell system includes: selecting means (e.g., a controller) for selecting a driving phase of the multiple-phase converter in accordance with the load of the load device; and driving means (e.g., a controller) for driving a plurality of driving phases, when selected by the selecting means, at carrier frequencies so that these driving phases are nearly opposite to each other.

Abstract: A fuel cell system includes: a converter disposed between a fuel cell and a load to increase an output voltage of the fuel cell; and a control unit that controls the converter at a predetermined duty ratio, wherein the control unit determines a duty command value for the converter from a feed-forward duty and a feed-back duty which are calculated using a command value of a reactor current that flows through a reactor in the converter and/or using a measurement value of the reactor current. In a low-load operation, the control unit sets, as a measurement value of the reactor current, a value obtained by multiplying a midpoint measurement value measured at an intermediate time of an on-duty period by a predetermined coefficient.

Abstract: In a fuel cell system which controls an operation of a converter on the basis of a duty command value including a feedforward term, the deterioration of a response of the converter at a time of a rapid increase (a rapid decrease) of a load is suppressed. There is disclosed a fuel cell system comprising a converter disposed between a fuel cell and a load device, and a controller for controlling the operation of the converter on the basis of the duty command value including the feedforward term, wherein the controller calculates the feedforward term by use of a command value of a physical amount concerning the converter in an operation range where a requested power from the load device is in excess of a predetermined threshold value.

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: A manufacturing method for a chopper circuit that uses soft switching operation includes: identifying devices that constitute the chopper circuit and that are relevant to determining time at which a voltage applied to a main switching element during operation of the chopper circuit takes a minimum value; calculating a design representative value of an observed device that is at least one of the identified devices in such a manner that a plurality of the observed devices are prepared and then variations from a rated value in electrical characteristic of each observed device are subjected to statistical processing; and setting the representative value, instead of the rated value of the electrical characteristic of the observed device, in a switching control unit that controls the timings of switching of the main switching element and an auxiliary switching element on the basis of the electrical characteristics of the identified devices.

Abstract: The power generation efficiency of a fuel cell system is improved. A fuel cell and an FC converter are integrally assembled so as to allow heat transfer therebetween, and are contained in the same casing. A control unit shifts a switching mode of a boost switch included in the FC converter from a soft switching mode to a hard switching mode when a temperature of the fuel cell is lower than a lower limit value of an allowable temperature range in accordance with an output of the fuel cell.