A power generation control system of a fuel cell includes: the fuel cell generating a power through a chemical reaction between fuel and air; a consuming device connected to an output terminal of the fuel cell and consuming the power output from the fuel cell; a converter connected between the fuel cell and the consuming device in series or parallel and adjusting an output voltage of the fuel cell; a supply device supplying the air to the fuel cell; a voltage controller controlling the converter on the basis of a required power or current of the fuel cell required to be output; and a supply controller controlling the supply device on the basis of the required power or current of the fuel cell required to be output.

In a case that activation is implemented on a fuel cell, a variable voltage is applied to a membrane electrode assembly while a first gas is supplied to an anode and a second gas is supplied to a cathode. Thereafter, while a constant voltage is applied to the membrane electrode assembly, liquid water is generated at the anode or the cathode. Alternatively, the membrane electrode assembly is made to generate electricity. During the generation of electricity, liquid water is generated at the anode or the cathode.

A method of measuring impedance of a fuel cell stack in a vehicle during driving of the vehicle includes: determining whether an impedance measurement of the fuel cell stack is requested during driving of the vehicle driven by power of the fuel cell stack; turning off a first relay connected between the fuel cell stack and a battery charged by the fuel cell stack when the impedance measurement of the fuel cell stack is requested; connecting a stack load to the fuel cell stack via a second relay and supplying air to the fuel cell stack; and measuring the impedance of the fuel cell stack.

A fuel cell system is equipped with a fuel cell unit that is composed of a plurality of fuel cells including a first fuel cell and a second fuel cell, a first supply device and a second supply device that supply reactive gas to the first fuel cell and the second fuel cell respectively, and a control device that controls running of the first fuel cell and the second fuel cell and operation of the first supply device and the second supply device. The control device suspends electric power generation by the first fuel cell and drives the first supply device to hold an opening circuit voltage of the first fuel cell within a target range, and suspends electric power generation by the second fuel cell and stops driving the second supply device when an output P required of the fuel cell unit is equal to 0.

A cooling water temperature of a fuel cell 10 is detected by a sensor 94d. Based on the outside air temperature, a first threshold temperature and a second threshold temperature lower than the first threshold temperature are calculated. When it is judged that the cooling water temperature is lower than the first threshold temperature and higher than the second threshold temperature, first warmup processing is performed. When it is judged that the cooling water temperature is lower than the second threshold temperature, second warmup processing with an amount of heat generation greater than the first warmup processing is performed.

A voltage control system includes: a converter controlling portion; a current value acquisition portion; and a voltage value acquisition portion. The converter controlling portion sets a duty ratio in a present cycle by adding an addition term to a feedforward term, the addition term being determined by use of a current deviation, which is a difference between a target value of an output current in the present cycle and a current measured value in a previous cycle, and the duty ratio in the previous cycle, the addition term being corresponding to an increase of the output current in the present cycle.

A fuel cell system and a method for operating the fuel cell system, wherein the fuel cell system includes a fuel cell, a controller, a switch, an oxygen supply device and an output circuit. The fuel cell includes an anode and a cathode. The fuel cell is a cathode enclosed fuel cell. The controller is used to drive control signal for adjusting the electrochemical metering ratio of oxygen flow, supplied by the oxygen supply device, to output current, wherein the electrochemical metering ratio is ‘a’, and ‘a’ satisfies: 1≤a≤4. The method of the present disclosure uses the fuel cell system of the present disclosure, which optimizes the performance of a fuel cell and makes the output interruption time very short; hence it is highly beneficial for providing a more stable output.

A fuel cell system includes a fuel cell, a supply device configured to supply a cathode gas to the fuel cell; and a control unit configured to execute recovery processing of causing a catalyst of the fuel cell to recover from performance deterioration by lowering an output voltage of the fuel cell. The control unit is configured to, when the recovery processing that has been executed is completed, control the supply device to place the fuel cell in a power generation paused state while making a stoichiometric ratio of the cathode gas lower than a stoichiometric ratio of the cathode gas in a normal operation state that is a state before execution of the recovery processing.

A fuel cell system wherein the fuel cell comprises an electrolyte membrane; wherein the electrolyte membrane is a perfluorosulfonic acid (PFSA) membrane; wherein the controller has a data group showing a correlation between the current of the fuel cell and the temperature of the fuel cell which is necessary to keep a moisture content of the electrolyte membrane at a predetermined moisture content threshold or more; and wherein, when the temperature and voltage of the fuel cell become a predetermined first temperature threshold or more and a predetermined voltage threshold or more, respectively, the controller conducts a temperature dropping time power generation mode in which power generation is conducted while controlling the current of the fuel cell with reference to the data group, until the temperature of the fuel cell becomes a predetermined second temperature threshold which is lower than the first temperature threshold.

A power supply system controls a voltage converter of a fuel cell output unit that has started up first among a plurality of fuel cell output units so that an output voltage of the fuel cell of the fuel cell output unit or an output voltage of the voltage converter becomes a target voltage when the plurality of fuel cell output units are controlled. Further, the system controls the voltage converter of a fuel cell output unit that has started up after the fuel cell output unit that has started up first among the plurality of fuel cell output units so that an output current of the fuel cell of the fuel cell output unit or an output current of the fuel cell output unit becomes a target current.