A low flow control method for a fuel cell includes: determining whether or not the fuel cell enters a low flow control mode, dividing a low flow control operation into a plurality of low flow control stages upon determining that the fuel cell enters the low flow control mode, and controlling a power generation quantity of the fuel cell according to the low flow control stages.

A fuel cell system comprises: a fuel cell stack; a turbo compressor configured to supply a cathode gas to the fuel cell stack through a cathode gas supply line; a pressure regulation valve configured to regulate a pressure of the cathode gas; and a controller, wherein the controller is configured to calculate a target rotation speed of the turbo compressor and a target opening position of the pressure regulation valve, based on a target flow rate of the cathode gas and a target pressure of the cathode gas that are determined according to a required power output of the fuel cell stack and to control the turbo compressor and the pressure regulation valve using the calculated target rotation speed and the calculated target opening position, and the controller is configured, upon increase of the required power output, to: (a) determine an acceptable overshoot level of a flow rate of the cathode gas that is to be supplied to the fuel cell stack, the acceptable overshoot level being selected from a plurality of levels based on at least an increased amount of the required power output; and (b) set a time change in opening position of the pressure regulation valve such that an overshoot amount in a change of the flow rate of the cathode gas becomes smaller as the acceptable overshoot level gets lower, and perform control of the pressure regulation valve. This configuration suppresses an excessive overshoot in the flow rate of the cathode gas.

Methods and systems are provided for cold-start of fuel cell stack in fuel cell vehicles. In one example, a method may include in response to cold-start of fuel cell vehicle, limiting the load drawn from the fuel cell stack. In addition, a coolant pump may be operated at a higher rate through a bypass loop to get heat quickly to the fuel cell stack to increase the solubility of water in the fuel cell stack to prevent ice formation. The net effect is that the fuel cell stack is then operated within the ice capacity of the membrane, and start-up at lower temperatures is possible without experiencing an intermittent performance drop due to active area freezing. Once the fuel cell stack is sufficiently warmed up, the coolant pump rate and fuel cell stack may be adjusted according to the demand.

A fuel cell equipped vehicle system in which an external power supply is coupled to an electric power supply line, the electric power supply line being coupled to a fuel cell, an electric power being input/output to/from a vehicular battery through the electric power supply line, the fuel cell equipped vehicle system performing an insulation test of the electric power supply line before charging the vehicular battery, the fuel cell equipped vehicle system including an insulation test unit configured to perform the insulation test of the electric power supply line; a switch that couples and cuts off between the fuel cell and the electric power supply line; and a control unit configured to control a coupling and a cutoff to/from the electric power supply line of the vehicular battery and control the switch, wherein the control unit is configured to cut off the vehicular battery from the electric power supply line and control the switch to cut off the fuel cell from the electric power supply line, and then drive the insulation test unit.

The present disclosure makes it possible to store data on the cause of an output shortage in a memory while reducing the capacity of the memory for storing data on an output shortage. A fuel cell system of the present disclosure comprises: a drive motor for driving a vehicle; a plurality of power sources that include a fuel cell and a secondary battery; a memory that stores data on a failure of output of the drive motor; and a controller that controls writing of the data on the failure into the memory. When an actual output value of the drive motor is smaller than a reference value decided by an output request value, the controller stores in the memory data on operating state of one of power sources, with an actual output value smaller than a power source output request value.

A control apparatus includes a control unit which instructs a constant temperature mode to the fuel cell unit as one of operation modes, the constant temperature mode being a mode for performing an control to cover power consumption of the auxiliaries by power supplied from the outside and an control to keep a temperature of the power generation unit constant within a prescribed temperature range. In the constant temperature mode, power output from the power generation unit is at least smaller than the power consumption of the auxiliaries.

The application describes a method for operating an electrolyzer and a fuel cell which, in parallel with one another, are connected to a device-side converter connection of a common bidirectional converter, on

A fuel cell power system and a method of starting a fuel cell power system. The fuel cell power system includes a fuel cell system having one or more voltage outputs, one or more DC/DC converters each having an output and an input, the input being connectable to the voltage outputs of the fuel cell system, a DC voltage link connectable to the output of the one or more DC/DC converters, and a local load connectable to the DC voltage link. In the system, the local load is adapted to draw power from the fuel cell system to decrease the voltage of the fuel cell system.

A fuel cell system and a fuel cell system control method are proposed. The fuel cell system includes a controller configured to control the opening ratio of an air recirculation valve or the speed of a hydrogen recirculation pump according to the required output of the fuel cell stack and a magnitude of an output voltage or output current.

A fuel cell device is improved for operating conditions during a partial load operation. The fuel cell device comprises a cell stack formed by electrically connecting fuel cells for generating power by fuel gas and oxygen-containing gas; a fuel gas supply unit for supplying the fuel gas to the fuel cells; and a power adjustment unit for adjusting the amount of current that is supplied to an external load and a controller for controlling the fuel gas supply unit and the power adjustment unit. The controller adjusts, during the partial load operation of the fuel cell device and when the fuel gas supplied to the cell stack is at a low flow rate. The relationship between a fuel utilization rate of the cell stack and the amount of power generated by the cell stack can be nonlinear.