A device for diagnosing a valve failure of a fuel cell system is capable of accurately and quickly determining whether an integrated valve in a fuel cell system is operated abnormally. and preventing problems caused by the operation abnormality of the integrated valve.

When an actual output value is less than an output command value, a current command value is increased. When the actual output value is equal to or greater than the output command value, whether the actual output value is within a range of a dead band is determined. When the actual output value is outside the range of the dead band, the current command value is decreased. When the actual output value is within the range of the dead band, the current command value is maintained.

An object is to provide a technique of reducing a potential failure to start a fuel cell system due to a temperature decrease in a vehicle with the fuel cell system mounted thereon. There is provided a vehicle that comprises a fuel cell system, a battery, a motor, and a determiner configured to determine that the fuel cell system has a frozen part when temperature measured by a temperature measurement unit is equal to or lower than a predetermined first temperature and at least one of conditions (1) to (3) is satisfied: (1) no purging process is performed after a change from an on state of the vehicle to an off state of the vehicle; (2) ambient temperature decreases to or below a predetermined second temperature in the off state of the vehicle and no purging process is performed; and (3) an inclination of the vehicle is equal to or greater than a predetermined inclination at a time of change from the off state of the vehicle to the on state of the vehicle.

The disclosed embodiments relate to the design of a portable and cost-effective fuel cell system for a portable computing device. This fuel cell system includes a fuel cell stack which converts fuel into electrical power. It also includes a fuel source for the fuel cell stack and a controller which controls operation of the fuel cell system. The fuel system also includes an interface to the portable computing device, wherein the interface comprises a power link that provides power to the portable computing device, and a bidirectional communication link that provides bidirectional communication between the portable computing device and the controller for the fuel cell system.

A Reversible Solid Oxide Fuel Cell (RSOFC) system includes a Reversible Solid Oxide Fuel Cell (RSOFC) unit, a bi-directional alternating current/direct current (AC/DC) converter, coupled to the RSOFC unit, a common bus, coupled to the bi-directional AC/DC converter and to a power grid, and a plurality of RSOFC subsystems, coupled to receive power only through the common bus. The RSOFC unit has a fuel cell mode, wherein the RSOFC unit produces electrical power from fuel, and an electrolysis mode, wherein the RSOFC unit consumes electrical power to produce the fuel. The bi-directional AC/DC converter is coupled to the RSOFC unit, and is configured to convert direct current (DC) electrical power produced by the RSOFC unit into outgoing alternating current (AC) power, and to convert incoming AC power into DC power for consumption by the RSOFC unit in electrolysis mode.

An illustrative example fuel cell power plant includes a cell stack assembly having a plurality of fuel cells configured to generate electricity based on an electrochemical reaction. The power plant includes a capacitor, a plurality of inverters, and at least one controller that is configured to control the plurality of inverters in a first mode and a second mode. The first mode includes the cell stack assembly associated with at least one of the inverters. A cell stack assembly and the associated inverter provide real power to a load external to the fuel cell power plant in the first mode. The second mode includes at least a second one of the inverters associated with the capacitor. The capacitor and the second one of the inverters selectively provide reactive power to or receive reactive power from a grid external to the fuel cell power plant in the second mode.

A fuel cell cooling system includes an air temperature estimating unit, an air temperature sensor and an abnormality determining unit. The air temperature sensor senses an air detection temperature of the air that flows out of the air cooler and is supplied to the fuel cell. The air temperature estimating unit estimates an air estimation temperature of the air, based on a temperature of a refrigerant flowing into the air cooler, a power supply quantity of a power supplied to the circulation pump, a temperature of the air flowing into the air cooler and a flow volume of the air. The abnormality determining unit determines that a circulation flow volume of the refrigerant is in an abnormal state when the air detection temperature is higher than the air estimation temperature by a value greater than or equal to a predetermined value.

A method and system for controlling a fuel cell vehicle are provided. The method includes determining, by a controller, a driving pattern of a driver based on driving information including acceleration and deceleration information. A condition for activation of an idling-stop of a fuel cell is then set based on the determined driving pattern and the fuel cell is stopped from generating electric energy when the condition for activation of the idling-stop is satisfied.

Each fuel cell apparatus among a plurality of fuel cell apparatuses is caused to transmit, as distinguishing information, at least one of a cumulative operating time and a rated power of the respective fuel cell apparatus to other fuel cell apparatuses. Each fuel cell apparatus is caused to receive distinguishing information transmitted by other fuel cell apparatuses. Each fuel cell is caused to select a fuel cell apparatus among the plurality of fuel cell apparatuses to be a master apparatus on the basis the distinguishing information of the respective fuel cell apparatus and the distinguishing information received from other fuel cell apparatuses.

A method of operating a redox flow battery string including at least first and second redox flow batteries and an outside power source includes: providing a least first and second redox flow batteries in a string electrically connected in a string, and each redox flow battery having a state-or-charge (SOC) and an electrical load, wherein the electrical load for at least one of the first and second redox flow batteries in the string is powered by the outside power source; obtaining an SOC value for each redox flow battery in the string; identifying a target SOC value in the string; and adjusting the SOC value for at least one of the first and second redox flow batteries to correspond to the target SOC value by using a portion of stored energy in the at least one first or second redox flow battery to supply power to the electrical load.