A DC voltage distribution arrangement and method of controlling a DC voltage distribution system, the DC voltage distribution system including a DC voltage bus, a fuel cell electrically connected to the DC voltage bus, an energy storage and an energy storage converter, wherein the input of the energy storage converter is connected to the energy storage and the output of the energy storage converter is connected to the DC bus. The method comprises providing a DC voltage reference for the energy storage converter, the energy storage converter controlling the voltage of the DC voltage bus by providing power from the energy storage or to the energy storage, detecting power flow of the energy storage converter, and changing the DC voltage reference on the basis of the detected power flow to change the power taken from the fuel cell.

Systems and methods are provided for using fuel cell staging to reduce or minimize variations in current density when operating molten carbonate fuel cells with elevated CO.sub.2 utilization. The fuel cell staging can mitigate the amount of alternative ion transport that occurs when operating molten carbonate fuel cells under conditions for elevated CO.sub.2 utilization.

Disclosed are self-powering biofuel cell and sensor devices, systems and techniques. In some aspects, a self-powered biosensing system includes an electronic circuit; an anode including an enzymatic layer electrically coupled to a power supply voltage terminal of the electronic circuit and configured to interact with an analyte in a fluid, such as glucose or lactate; and a cathode electrically coupled to a ground voltage terminal of the electronic circuit, where the electronic circuit is operable to control and use the electrical energy generated at the anode and cathode for powering the biosensing system and detecting a concentration of the analyte in the fluid.

A fuel cell system includes a fuel cell stack and a control device. The control device raises the voltage of the fuel cell stack until a predetermined voltage condition is met, by supplying a cathode with an oxidant gas before current sweep is started when the fuel cell system is started and a value measured by a temperature sensor is equal to or less than a temperature determined in advance. The control device executes stand-by control, in which a current command value is kept constant, when a measured voltage value reaches a control start voltage value smaller than a voltage command value in a transition period, and ends the stand-by control by permitting a change in the current command value when the measured voltage value reaches a permission voltage value equal to or more than the voltage command value during execution of the stand-by control.

A fuel cell system includes: a fuel cell; a target operating point determination unit that determines a warm-up target operating point based on a required electric power amount during warm-up and a required heat generation amount during warm-up; an operation control unit; and a failure state identification unit that identifies whether an electric power consumption device that operates by consuming generated electric power generated by the fuel cell has failed. When a failure of the electric power consumption device is identified, the target operating point determination unit determines an operating point that satisfies a required electric power amount during a failure that is set to be smaller than the required electric power amount during the warm-up and a required heat generation amount during the failure that is set to be smaller than the required heat generation amount during the warm-up as a target operating point during the failure.

A catalyst deterioration suppression device includes: a first device obtaining a fuel cell voltage V (=catalyst voltage V.sub.cat) as a variable to estimate a response speed (time constant τ) at which a coverage ratio of an oxide film of catalyst particles contained in a fuel cell cathode changes; a second device reading out a time constant τ.sub.t corresponding to the voltage V at a current time t from a pre-made map A representing a relationship between the voltage V and the time constant τ and corresponding to the catalyst particles; a third device generating a continuous-time type dynamic filter F(s, τ) by using the time constant τ.sub.t and converting the continuous-time type dynamic filter F(s, τ) to a discrete-time type dynamic filter F(z, τ); and a fourth device inputting a target voltage Vr to the discrete-time type dynamic filter F(z, τ) and outputting a corrected target voltage V.sub.r-fil.

Proposed is a fuel cell power control system. A fuel cell generates electric power. A load unit is electrically connected to the fuel cell. A DC/DC converter is disposed between the fuel cell and the load unit to convert the electric power between a low side of the DC/DC converter electrically connected to the fuel cell and a high side of the DC/DC converter electrically connected to the load unit. A battery is electrically connected to the high side of the DC/DC converter to be parallel to the load unit. A controller monitors a voltage of the load unit, the battery, or the high side of the DC/DC converter, and controls the electric power input to the load unit or output from the load unit in accordance with the monitored voltage.

A fuel cell system in which a fuel cell is coupled to a motor driving battery and a vehicular auxiliary machine is coupled to the motor driving battery via a first voltage converter, the fuel cell system including a fuel cell auxiliary machine coupled to the first voltage converter; and a second voltage converter that couples the fuel cell auxiliary machine to the fuel cell.

A method of controlling a fuel battery system of the present disclosure is a method of controlling a fuel battery system, including a measurement process in which a power generation voltage at a predetermined current density of a fuel battery cell is measured, a first calculation process in which a poisoning rate of an electrode catalyst at the power generation voltage measured in the measurement process is calculated from a predetermined relationship between the power generation voltage at the predetermined current density and the poisoning rate of the electrode catalyst of the fuel battery cell, and a second calculation process in which a generation rate of hydrogen peroxide at the poisoning rate of the electrode catalyst calculated in the first calculation process is calculated from a predetermined relationship between the poisoning rate of the electrode catalyst and the generation rate of hydrogen peroxide of the fuel battery cell.

A fuel cell system includes a supply valve for supplying an anode gas into an anode system, a purge valve for discharging an off-gas from the anode system, a pressure detecting portion configured to estimate or measures a pressure inside the anode system, a supply valve control portion configured to control an open/close operation of the supply valve based on a load of the fuel cell, a purge flow rate estimating portion configured to estimate a purge flow rate of the off-gas discharged from the anode system through the purge valve based on a pressure decrease inside the anode system in a supply valve close state, and a purge valve control portion configured to open the purge valve in synchronization with the supply valve close state.