Abstract: For carrying out a heterogeneously catalyzed reaction, such as the generation of hydrogen from hydrocarbons or alcohol, a reaction mixture comprising a hydrocarbon and water is supplied to a catalyst, which is produced by pressing at least one catalyst powder into a layer. Instead of a metallic housing, stacked layers are sealed by an edge seal, introduced into the layer or applied on the layer.

Abstract: A method for removing carbon monoxide from a gas stream, in which the gas stream loaded with CO is guided through a device, and the CO is removed from the gas stream through adsorption on the working electrode. As a function of an electrical voltage between the working electrode and the counter electrode, or between the working electrode and the reference electrode, an electrode cleaning mode is enabled by triggering a current flow between the working electrode and the counter electrode, and the CO adsorbed on the working electrode is oxidized to CO2.01.

Abstract: Techniques for determining root mean square (RMS) values of a signal for controlling operation of grid-linked converters, such as DC-to-AC inverters, via squaring the signal, sampling the squared signal n times during a cycle period to obtain n samples, summing the first n−1 samples to obtain a first value, multiplying the first value by a sampling time and a frequency of the signal to obtain a second value, determining a compensation factor, adding the compensation factor to the second value to obtain a third value, and determining a square root of the third value to obtain a RMS result.

Abstract: A process for preparing a graft copolymers is provided comprising exposing a polymeric base material to a dose of ionizing radiation, and then contacting the irradiated base material with a microemulsion comprising at least one fluorostyrenic monomer, water and water-miscible solvent. The graft copolymer may be formed into a membrane, including ion exchange membranes.

Abstract: A process for manufacturing a membrane electrode assembly for an electrochemical cell comprises: feeding a sheet of ion exchange membrane material through a double belt press; feeding at least one electrode substrate through the double belt press; and applying heat and pressure to bond a portion of the membrane material and the electrode substrate within a process zone of the double belt press. An apparatus for manufacturing membrane electrode assemblies for an electrochemical cell comprises a double belt press. The present process can further comprise cutting a membrane electrode assembly, such as by longitudinal slitting to obtain strips of the desired width and/or cross-cutting of the strips to obtain a membrane electrode assembly of the desired length.

Abstract: A method for embossing expanded graphite sheet material comprises removing at least a portion of the gas from within the material by exposing the material to a pressure less than atmospheric pressure, and then embossing the material. The pressure to which the material is exposed is preferably no greater than about 400 torr. An apparatus for embossing expanded graphite sheet material at a pressure less than atmospheric pressure comprises: an embossing device, a compression device adapted to urge the embossing device against the material, an embossing chamber comprising the at least one embossing device and adapted to receive the material and to be substantially gas-tight at least when the embossing device is urged against the material by the pressing device, and an evacuation device for reducing the pressure within the embossing chamber.

Abstract: A dual power module architecture employing a high degree of modularity, that allows a base power module to be quickly, easily, and cost effectively configured to address a large variety of applications.

Abstract: A power module employs at least one capacitor electrically coupled across the input terminals to reduce voltage overshoot. The capacitor may be surface mounted to a high side collector plating area and a low side emitter plating area.

Abstract: An ultracapacitor based power storage device suitable for use in hybrid fuel cell systems and other power systems includes circuitry for simulating the response of a battery. A voltage current limiting circuit may be employed with a variety of electrical storage devices, for example, ultracapacitors and batteries.

Abstract: A power converter utilizes a high frequency capacitor and a bulk capacitor coupled across the DC terminals to reduce high frequency effect and voltage overshoot, leading to space and cost savings in power converter design. Each capacitor may be physically coupled adjacent the gate driver board via clips, clamps, and/or fasteners.

Abstract: An array of fuel cell systems are electrically couplable in series and/or parallel combinations to provide a variety of output powers, output current and/or output voltages. The fuel cell systems are “hot swappable” and redundant fuel cell systems may automatically replace faulty fuel cell systems to maintain output power, current and/or voltage, with or without switching. The configuration of fuel cell systems may be automatic and may be based on desired power, current and/or voltage, and/or based on the operating parameters of the fuel cell systems and/or power supply system.

Abstract: A method fabricates fluid flow field plates that are suitable for use in an electrochemical fuel cell assembly. Pursuant to the method, a fluid flow field channel region such as, for example, substantially straight, parallel fluid flow field channels, is roller embossed in a sheet of compressible, electrically conductive material such as, for example, expanded graphite sheet material. A fluid distribution region such as, for example, a region containing manifold openings and supply channels, is then reciprocally embossed in the sheet material. A sheet pre-impregnated with a curable polymeric composition, such as pre-impregnated expanded graphite, can be employed, with the curing step being performed after the roller embossing and reciprocal embossing steps.

Abstract: Current pulsing improves the performance of fuel cells in a fuel cell stack based power system. Voltage clamping limits the voltage peaks that occur after a current pulse. In a hybrid power system, an electric storage device supplies the loads during current pulsing. The electric storage device may sink current to achieve the voltage clamping, and/or power system may employ other the voltage clamping circuits.

Abstract: Liquid cooled systems having coolant circulation loops must often operate in below freezing conditions. For instance, in various applications certain fuel cell systems must be able to tolerate repeated shutdown and storage in below freezing conditions. Conventional glycol-based coolants typically used for internal combustion engines are generally unsuitable for use in the associated fuel cell cooling subsystems due to the presence of additives and/or inhibitors which are normally included to deal with problems relating to decomposition of the glycol. With additives or inhibitors present, the coolant conductivity can be sufficiently high as to result in electrical shorting or corrosion problems. However, provided the purity of the coolant is maintained, a pure glycol and water coolant mixture may be used as a fuel cell system coolant to obtain suitable antifreeze protection. Adequate purity can be maintained by including an ion exchange resin unit in the cooling subsystem.

Abstract: Systems and methods for controlling and/or calculating the torque for a field oriented induction motor operating at a given stator frequency. The systems and methods include calculating the torque using a first algorithm when the motor is at or below a first predetermined stator frequency, a second algorithm when the motor is at or above a second predetermined stator frequency, and a third algorithm when the motor is between the first predetermined stator frequency and the second predetermined stator frequency.

Abstract: An electrochemical power generation system includes a fuel cell stack having an oxidant delivery system for delivering air from the ambient environment to the oxidant inlet of the stack, an oxygen sensor for measuring the oxygen concentration of ambient air in the vicinity of the power generation system. A controller coupled to the oxygen sensor is configured to cease operation of the power generation system when the oxygen concentration of the ambient air in the vicinity of the power generation system falls below an oxygen concentration threshold. The power generation system may also include a purge valve associated with a fuel outlet from the stack.

Abstract: Methods and systems for use with an electric machine which reduce magnetic leakage paths, improve d-axis flux, and/or reduce stress levels at high operating speeds.

Abstract: A fuel cell based power supply comprises a main power converter architecture that allows the fuel cell stack to operate independently of a desired output voltage. The fuel cell stack may be directly connected to the main power converter eliminating high current switches and diodes. Switches are operable to selectively power an auxiliary component such as a cooling fan to the fuel cell stack or to a storage device via an auxiliary power converter. A single auxiliary power converter can replace a dedicated cooling fan power supply. The power supply operates in a variety of states.

Abstract: A fuel cell based power supply comprises a main power converter and control that allows the fuel cell stack to be electrically shorted from time-to-time to improve performance. Additionally, the power converter may temporarily disconnect the fuel cell stack from the load after shorting, allowing the fuel cell stack to return to an open circuit voltage, and/or provide current limiting during a period after shorting to provide stable operation while the fuel cell stack powers the load and recharges a power storage device.

Abstract: A catalyst element for a stacked reactor for generating hydrogen from hydrocarbons includes a catalyst disc of porous material and a solid connection element. The catalyst-side end of the connection element is at least partially enclosed by the catalyst disc and is connected to this disc. The catalyst-side end of the connection element may have a mediator layer that is joined to the connection element over the entire area by sintering, soldering, or adhesive bonding. The mediator layer is joined to the catalyst disc over the entire area by sintering. Attachment means are provided at the exposed end, which is remote from the catalyst, of the connection element.