A fuel cell system includes a fuel cell generator, a rechargeable energy storage circuit, an auxiliary load, a converter circuit, and a switch circuit. The fuel cell generator is operable to generate electrical power in a stack output signal. The auxiliary load is powered by the rechargeable energy storage circuit while in a first mode, and powered by a local signal while in a second mode. The converter circuit is operable to convert the stack output signal into a plurality of recharge signals while in the first mode and in the second mode, and convert the stack output signal into the local signal while in the second mode. The switch circuit is operable switch the plurality of recharge signals to one or more electric vehicles, and switch the local signal to the auxiliary load while in the second mode.

A fuel cell system includes: a fuel cell that generates power by being supplied with a reaction gas; an air pressure regulator that regulates an air pressure, which is a pressure of an oxidant gas passing through the fuel cell; and a control device that controls a power generation amount of the fuel cell. When the air pressure is higher than a predetermined high-pressure reference value while a required output to the fuel cell shows a decreasing tendency, the control device limits or delays a reduction in the power generation amount of the fuel cell in response to a decrease in the required output. Alternatively, when the air pressure is lower than a predetermined low-pressure reference value while the required output to the fuel cell shows an increasing tendency, the control device limits or delays an increase in the power generation amount of the fuel cell.

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 condensate water drain control system for fuel cells includes a fuel cell stack configured to generate electric power through chemical reaction, a fuel supply line configured to recirculate fuel discharged from the fuel cell stack together with fuel introduced from a fuel supply valve, a water trap located in the fuel supply line, the water trap being configured to collect condensate water discharged from the fuel cell stack, a drain valve configured to discharge the condensate water stored in the water trap to the outside when opened, and a drain controller configured to determine whether the fuel supply valve is controlled such that pressure in the fuel supply line is maintained before the drain valve is opened and to sense discharge of fuel from the fuel supply line through the drain valve upon determining that the pressure is maintained.

A fuel cell system including an air discharge valve provided in an air discharge path, through which air discharged from a fuel cell stack flows, a bypass valve provided in a bypass path connecting an air supply path and the air discharge path and bypassing the fuel cell stack, and a controller for controlling the air discharge valve to make an opening degree of the air discharge valve smaller than full opening, controlling the bypass valve to make the opening degree of the bypass valve larger than fully closure, and controlling a compressor to supply air to the air supply path through which the air to be supplied to the fuel cell stack flows.

The present invention relates to a power converter system for a plurality of electrolysis cell stack units, comprising: a parallel arrangement of multiple DC/DC converter modules;

wherein each DC/DC converter module is configured to power a single electrolysis cell stack unit; and wherein each DC/DC converter module is capable of supplying the electrolysis cell stack unit with a predetermined variation of current, power and/or voltage such that near-thermoneutral operation at part load is enabled by matching the integral Joule heat production with the integral reaction heat consumption inside the electolysis cell stack unit, and/or wherein each DC/DC converter module is capable of reversing the current supplied to said electrolysis cell stack unit, causing said electrolysis cell stack unit to perform in fuel cell mode. The power converter system enables facilitated and inexpensive power distribution, long lifetime, as well as improved thermal management during operation of the electrolysis cell stacks. In further aspects, the invention relates to a power distribution system and electrolysis plant comprising said power converter system, as well as to related methods.

A fuel cell system for a load device may include a fuel cell, a battery, and a controller configured to control the fuel cell and the battery. The controller may be configured to: cumulatively calculate first accumulated electric energy generated by the fuel cell; cumulatively calculate a power generation efficiency average at the time of storage of the first accumulated electric energy; calculate required power generation efficiency to generate electric power that meets a power demand of the load device; under a first condition where the power generation efficiency average is lower than the required power generation efficiency, cause the fuel cell to generate electric power that meets the power demand; and under a second condition where the power generation efficiency average is higher, cause the fuel cell to generate electric power at a specific operating point and cause the battery to discharge deficient electric power.

A fuel cell system includes a controller for controlling an oxygen-containing gas supply device and a fuel gas supply device. The controller causes a fuel cell stack to perform specific power generation for a first predetermined time for increasing water in the fuel cell stack after stopping normal operation of the fuel cell system, and thereafter supplies an oxygen-containing gas to the fuel cell stack for a second predetermined time to reduce water inside the fuel cell stack.

A fuel cell vehicle includes a cell stack, a DC level converter, an output unit, a first switching unit disposed between a positive output terminal of the DC level converter and a positive input terminal of the output unit, a second switching unit disposed between a negative output terminal of the DC level converter and a negative input terminal of the output unit, a resistor and a third switching unit connected to each other in series between the positive output terminal of the DC level converter and the negative output terminal of the DC level converter, a fourth switching unit disposed between a contact point between the resistor and the third switching unit and the positive input terminal of the output unit, and a controller for controlling switching operation of the first, second, third and fourth switching units according to an operation mode.

A charging system may include a plurality of fuel cell stacks configured to receive hydrogen from a hydrogen supply unit and generate power, a plurality of charging dispensers configured to be electrically connected to a load device and configured to provide power upon connected to the load device, and a controller configured to distribute and supply the power generated by the plurality of fuel cell stacks to a charging dispenser to which the load device is connected, to compare a total available power amount of the plurality of fuel cell stacks with a total power demand amount of the charging dispenser to which the load device is connected, and to control a power generation amount of each of the plurality of fuel cell stacks according to a result of the comparing.