Disclosed are an apparatus for measuring an impedance of a fuel cell in a system to which a DC-DC converter is applied and a method thereof. The method includes calculating an impedance of a fuel cell stack based on an impedance of an output terminal of the fuel cell stack measured in a state in which the output of the fuel cell stack is drawn and the impedance of the output terminal of the fuel cell stack measured in a state in which the drawing of the output of the fuel cell stack is stopped.

A method of controlling a fuel cell device includes: a step of determining whether impedance between a fuel electrode and an oxidant electrode is greater than a predetermined threshold during a steady operation of the fuel cell device; a step of decreasing a flow rate of a gas circulating via a circulation passage connecting a gas introduction passage of the gas supply unit to a gas discharge passage when the impedance is greater than the predetermined threshold; a step of measuring the voltage between the fuel electrode and the oxidant electrode when the impedance is equal to or less than the predetermined threshold, and determining whether the voltage is equal to or less than a first predetermined threshold; and a step of increasing the flow rate of the gas circulating via the circulation passage when the voltage is equal to or less than the first predetermined threshold.

A computer-implemented method determines a degradation state of a turbo and/or a humidifier of a fuel cell system for a vehicle. The fuel cell system includes a fuel cell stack, the turbo and the humidifier. The method includes obtaining a fuel cell system efficiency value which corresponds to a measured efficiency decrease of the fuel cell system during use with respect to a first reference efficiency, obtaining a fuel cell stack efficiency value which corresponds to a measured efficiency decrease of the fuel cell stack during use with respect to a second reference efficiency, and determining the degradation state of the turbo and/or the humidifier based on a difference between the fuel cell system efficiency value and the fuel cell stack efficiency value.

A system and a method for measuring impedance of a fuel cell stack are disclosed. The system includes: an energy consumption device, a cooling device, and a high-voltage battery connected in parallel to a main bus end of a fuel cell stack; a relay provided at the main bus end and configured to electrically connect or disconnect the cooling device and the high-voltage battery to or from the fuel cell stack; an impedance measurement unit configured to apply an AC current to the fuel cell stack and to measure the impedance of the fuel cell stack; and a controller configured to turn off the relay during measurement of the impedance of the fuel cell stack.

A method and system for controlling air flow is arranged to reduce power consumption of an air blower or an air compressor by controlling air flow, enhance stack performance by preventing stack dry-out that is more likely to occur in a low-flow range, and improve durability of the stack by decreasing frequency of exposure to high voltages.

There is provided a fuel cell system having a fuel cell, which determines whether an operating state thereof is a low-temperature-startup operation or a normal-running operation and performs recovery control for increasing a concentration gradient of water in an electrolyte membrane of the fuel cell to be greater than that in the normal-running operation when it is determined that the operating state is the low-temperature-startup operation.

A control method for a fuel cell system that includes a solid oxide fuel cell configured to generate power upon receipt of supply of an anode gas and a cathode gas includes an anode protection execution determination process of performing execution determination of an anode protection process of applying a predetermined protection current to the fuel cell in order to restrain catalyst oxidation in an anode of the fuel cell. In the anode protection execution determination process, an internal impedance of the fuel cell at an anode response frequency at which an anode reaction resistance of the fuel cell is detectable is acquired, and based on the internal impedance at the anode response frequency, whether the anode protection process is to be executed or not is determined.

A method for controlling a fuel cell system including a fuel cell, includes generating electric current via an electrochemical reaction between a fuel gas and an oxidant gas by the fuel cell including a solid polymer electrolyte membrane. An impedance of the fuel cell is detected. It is determined whether the impedance reaches a threshold impedance. The electric current generated by the fuel cell is increased when the impedance is determined to reach the threshold impedance.

An energy conversion arrangement configured to convert chemical energy into electrical energy. The energy conversion arrangement comprises plural cell groups (30, 32, 34, 36), each cell group being configured to convert chemical energy into electrical energy. The energy conversion arrangement also comprises at least one measurement arrangement (38,40,42,44,46) configured to make measurements at each of the plural cell groups (30, 32, 34, 36). Each energy conversion arrangement is configured to determine a condition of at least one of: each of the plural cell groups; and the energy conversion arrangement. The condition is determined in dependence on the measurements made at each cell group and a model of each cell group.

An apparatus and method for controlling operation of a fuel cell system is provided. The method includes measuring a stack current and a stack insulation resistance. The measured stack current is compared with a predetermined current reference value and the measured stack insulation resistance is compared with a predetermined first insulation reference value. An air supply amount to a fuel cell stack is increased during a predetermined time when the measured stack current is less than the predetermined current reference value and the measured stack insulation resistance is less than or equal to the predetermined first insulation reference value.