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 voltage synchronization method and system are provided. The system includes a main controller that is configured to determine whether voltage synchronization is possible. When the voltage synchronization is determined to be possible, the main controller is configured to transmit a voltage synchronization command to a plurality of auxiliary controllers. The plurality of auxiliary controllers are configured to adjust sensed voltages based on an output voltage of a fuel cell stack when the transmitted voltage synchronization command is received.

A system control method is provided for measuring a distance between a smart key and a vehicle. When the distance between the smart key and the vehicle is changed based on a predetermined distance whether a hydrogen leak occurs is detected by a hydrogen sensor detection controller. A driver is then informed of a hydrogen leak via a display on a cluster, a turn-on of an emergency light, and a warning sound of the vehicle. Alternatively, a starting-impossible state of the vehicle or shutting-down starting of the vehicle is maintained to ensure safety measures based on the concentration of the leaking hydrogen.

A device for protecting a converter and a control method thereof, the device including: a voltage detection unit that detects at least one of an input-stage voltage and an output-stage voltage of a converter; a switching device that connects an output stage of the converter and a load connected to the output stage, or blocks a connection; a controller that determines whether the detected input-stage voltage or output-stage voltage is out of a preset voltage range, and, when the voltage is out of the range, controls the switching device to cut off the connection between the output stage of the converter and the load; and a driving unit that controls an operation of at least one of the fuel cell and the battery so that a driving force of the vehicle is not generated by the fuel cell and the battery when the connection is cut off.

In order for a vehicle to which a fuel cell module is mounted to fully secure an electric connection between a vehicle body and the fuel cell module, a vehicle is provided, which includes a conductive plate-like member, constituting at least a part of a floor portion of a vehicle body of the vehicle, and having a protruded portion protruded upwardly in the gravity directions and extended from the front to the rear of the vehicle, a fuel cell module, provided downward in the gravity directions from the plate-like member, and accommodating a fuel cell, and a grounding wire, electrically connecting the fuel cell module with the plate-like member within a range when seen in the gravity direction where the protruded portion exists.

In one aspect, an apparatus and a method for monitoring a hydrogen storage system of a vehicle to always monitor the hydrogen storage system of the vehicle are provided. The apparatus comprises a first temperature sensor that measures an internal temperature of a hydrogen tank, a second temperature sensor that measures an outdoor temperature, a comparator that determines whether a hydrogen leak occurs based on the result of comparing the internal temperature with the outdoor temperature and outputs a wake-up signal, and a controller that performs failure diagnosis of a hydrogen storage system, when receiving the wake-up signal.

A system and method for recovering an output of a fuel cell is provided. The system and method for recovering an output of a fuel cell includes: an output recovering device connected to a fuel cell stack through at least one coolant heater line; and a vehicle controller configured to communicate with the output recovering device and control supply of a coolant, air, and hydrogen to the fuel cell stack. The output recovering device also includes a current supplier configured to supply a current to the fuel cell stack and a controller configured to communicate with the vehicle controller and control the current supplied from the current supplier.

The disclosure generally describes a method for venting pressurized hydrogen gas from a device for simulating a refueling operation for a fuel cell electric vehicle (FCEV).

Systems and methods are provided for monitoring and controlling pump speeds to maintain a balanced pressure drop between each of the multiple fuel cell systems or circuits. In systems where a single radiator is used to maintain desired temperatures of multiple fuel cells, back flow can nevertheless be avoided. Control maps may be used to meet minimum pump speeds as a function of a flow splitting valve position and target flow rate (to prevent or avoid fluid back flow through a fuel cell stack). Control maps may also be used to determine a minimum pump speed as a function of three-way valve position (to prevent fluid back flow across a radiator path).

A fuel cell vehicle is provided. The fuel cell vehicle includes a fuel cell including a cell stack configured such that a plurality of unit cells is stacked, a drive motor unit disposed below the fuel cell, a purge valve / drain valve assembly configured to discharge unreacted hydrogen and first condensate water flowing together out of the fuel cell, an air exhaust line configured to discharge unreacted oxygen and second condensate water flowing together out of the fuel cell, and a hydrogen exhaust line connecting the purge valve / drain valve assembly to the air exhaust line and disposed so as to avoid interference with the drive motor unit.