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.

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 fuel cell voltage monitor (12a, 12b, 40, 140, 440) detects and may respond to, a problematic operating condition at or near a fuel cell (10) or within a subset (n) of fuel cells, as in a fuel cell stack assembly (110). Two or more co-planar, spaced voltage leads or contacts in a fuel cell plane, as at a separator plate, detect the presence of a voltage difference within the plate/plane as an indication of an operating problem at or near the fuel cell. Placement of such arrangements of at least two spaced voltage leads at various subset intervals (n), of fuel cells in a stack assembly allow monitoring for such problems throughout the stack assembly, either by analysis of voltage difference between co-planar leads at respective individual fuel cells or by comparison of voltage differences between aligned pairs of voltage leads at opposite ends of a subset.

A fuel cell system includes a fuel cell, a fuel gas supply/exhaust portion, an oxidant gas supply/exhaust portion, a cooling portion, and a controller. The controller performs at least one of a transient increase control process and a transient decrease control process. In the transient increase control process, the controller determines whether a temperature of a coolant is in a transient increase state. In the transient increase state, the controller performs an oxidant gas pressure increase process. In the transient decrease control process, the controller determines whether the temperature of the coolant is in a transient decrease state. In the transient decrease state, the controller performs at least one of the oxidant gas pressure increase process and an output increase process. In the output increase process, the controller controls the fuel cell to generate an output higher than a target output corresponding to a request output.

A fuel cell system that includes a fuel cell and a secondary battery, each acting as a power supply source. A first converter a second converter is provided between the fuel cell and the secondary battery and first and second loads. A first inverter is provided between the first and second converters and the first load and a second inverter is provided between the first and second converters and the second load. A first controller controls an output of the fuel cell by controlling the first converter, and a second controller is configured separately from the first controller. If one of the first controller and the second controller receives the failure information sent from the other, the first controller or the second controller that has received the failure information stops operation of the control target thereof.

A method of controlling a fuel cell system includes supplying a fuel gas from a fuel-gas storage container to a fuel cell via a drive valve provided in a fuel-gas path. A first pressure is detected in the fuel-gas path between a first decompression mechanism and a second decompression mechanism. A second pressure is detected in the fuel-gas path between the second decompression mechanism and the drive valve. An on-off valve is opened. The on-off valve is provided in a bypass path. The first pressure and the second pressure are compared after the on-off valve has been opened. The fuel cell system is controlled to decrease electric power generated by the fuel cell or to stop generating electric power in the fuel cell when the first pressure is not substantially equal to the second pressure.

A method for operating a fuel cell vehicle includes supplying electric power to a vehicle drive motor from at least one of a fuel cell and a battery. It is determined whether an electric potential of electric power output from the fuel cell is within a deterioration acceleration region in which the fuel cell is deteriorated due to a platinum oxidation-reduction reaction. The fuel cell is controlled in a deterioration suppressing mode when the electric potential is within the deterioration acceleration region in a state where the fuel cell and the battery supply electric power to the vehicle drive motor.

A fuel cell system to be installed on a vehicle includes a fuel cell, a secondary battery, an SOC detector that detects a temperature and a state of charge of the secondary battery, an accelerator position detector that detects an accelerator depressed amount, and a controller that controls power to be generated by the fuel cell. The controller includes: a required generation power calculator that calculates required generation power based on the accelerator depressed amount and the temperature and the state of charge of the secondary battery; and a maximum required power calculator that calculates maximum required power based on the accelerator depressed amount and the temperature and the state of charge of the secondary battery. The maximum required power includes allowable charging power correlated with a maximum value of charging power. If determining that a condition for rapid reduction in consumption power of a motor is satisfied, the controller sets the allowable charging power to zero and calculates the maximum required power. If the required generation power exceeds the maximum required power, the controller makes the fuel cell generate power responsive to the maximum required power.

An apparatus and a method for measuring the internal ohmic resistance of a fuel cell system, in which the resistance can be easily measured through a current interruption method even while the fuel cell system is operated. An interrupter and an external energy consumption device are connected in parallel to each other between a fuel cell and a main energy consumption device such that current to the external energy consumption device is applied and interrupted by switching the interrupter on/off even while the fuel cell system is maintained in operation as is, thereby making it possible to easily measure the internal ohmic resistance of the fuel cell.

In a fuel cell system for supplying a fuel gas from a fuel container to a fuel cell through injectors, in a case where a generated current of the fuel cell is equal to or greater than a detection-effective current threshold, failure determination for the injectors is performed based on a fuel gas pressure command value and a gas pressure detection value detected by each of pressure sensors provided downstream of the injectors.