A fuel cell driving method of an embodiment includes applying a voltage with a potential cycle including repetitions of low potential and high potential by use of a power supply connected to an anode and a cathode of a membrane electrode assembly having the anode, an electrolyte membrane, and the cathode. The low potential is 0.85 V or less for the cathode with reference to a potential of the anode. The high potential is 1.10 V or more for the cathode with reference to a potential of the anode.

An electric power adjustment system includes a fuel cell connected to a load, and a multi-phase converter connected between the fuel cell and the load. The multi-phase converter is constituted of a plurality of phases and converts an output voltage from the fuel cell by a predetermined required voltage ratio. The electric power adjustment system includes a ripple current characteristic switching unit configured to switch a ripple current characteristic with respect to an input current to the multi-phase converter by changing at least one of a drive phase number and the voltage ratio of the multi-phase converter according to an operation state of the fuel cell and a required electric power of the load.

There is provided a fuel cell system. This fuel cell system comprises a fuel cell configured to generate electric power using reactive gases; a voltage sensor configured to measure a voltage output from the fuel cell; a converter configured to boost an input voltage that is input from the fuel cell; and a controller configured to control the converter. In the case where the voltage output from the fuel cell to the converter is to be boosted after a changeover of an operating state of the fuel cell system from an intermittent operation to an ordinary operation, when a duty ratio D1 calculated by Mathematical Formula I is greater than a duty ratio D2 calculated by Mathematical Formula II, the controller causes the converter to boost the voltage output from the fuel cell at the duty ratio D2.

[00001]$\begin{array}{cc}\left[\mathrm{Math}..Math.1\right].Math.& \\ D.Math..Math.1=1-\frac{\mathrm{Vltrg}}{\mathrm{VH}}& \left(I\right)\end{array}$

where VH (V) denotes a value of output voltage that is output from the converter, and Vltrg (V) denotes an estimated value of voltage that is output from the fuel cell,

[00002]$\begin{array}{cc}\left[\mathrm{Math}..Math.2\right].Math.& \\ D.Math..Math.2=1-\frac{\left(\mathrm{Vl}+\mathrm{Vlmrg}\right)}{\mathrm{Vhul}}& \left(\mathrm{II}\right)\end{array}$

where Vl (V) denotes a measured value of voltage of the fuel cell by the voltage sensor, Vlmrg (V) denotes a cor

An electrical system includes: a battery; a fuel-cell pack; a load electrically coupled to the fuel-cell pack; a switching arrangement electrically coupled to the battery, the fuel-cell pack and the load; a DC-DC converter; and a control system. The switching arrangement configures the electrical system in at least one of a battery-charge mode and a combined-drive mode. In the battery-charge mode the battery is coupled in series to the fuel-cell pack and the load via the DC-DC converter for simultaneous charging of the battery and driving of the load by the fuel-cell pack. In the combined-drive mode, the battery is coupled in series to the fuel-cell pack and the load via the DC-DC converter for driving of the load by both the battery and the fuel-cell pack. The control system is configured to: monitor a parameter of an electrical power provided to the load; and control the DC-DC converter.

A method of improving the electrical performance of an operating fuel cell catalyst-containing cathode in a fuel cell connected to an electrical load by: reducing the flow of air to the cathode; disconnecting the load from the fuel cell; connecting a potentiostat to the fuel cell; cycling an applied voltage, current, or power to the fuel cell one or more times; disconnecting the potentiostat from the fuel cell; reconnecting the load to the fuel cell; and resuming the flow of air to the cathode.

A method for controlling starting of a fuel cell vehicle is provided. The method includes measuring a time interval for stopping of a fuel cell and a cell average voltage of the fuel cell when the fuel cell vehicle stops. A starting mode is then switched to a catalyst activating mode when the time interval exceeds a predetermined time or the cell average voltage is greater than a predetermined voltage. The cell average voltage is decreased to be less than the predetermined voltage and the fuel cell is started by supplying air to a cathode of the fuel cell.

A control method of a cooling water pump of fuel cell vehicle is provided. The method includes comparing a derived temperature value, including a cooling water temperature of a fuel cell or an estimated temperature of a stack of the fuel cell, with predetermined temperature criteria and comparing a required output value of the stack of the fuel cell with predetermined output criteria. The cooling water pump is then operated in a normal mode when the derived temperature value is greater than the temperature criteria or when the required output value is greater than the output criteria. Additionally, the cooling water pump is operated in a stop mode when the derived temperature value is less than the temperature criteria and, simultaneously, when the required output value is less than the output criteria.

A fuel cell power controller tracks load current and fuel cell output voltage, and alerts on excessive fuel cell ramp rate, so another power source can supplement the fuel cell and/or the load can be reduced. A power engineering process makes efficient use of available fuel cell power by ramping up power flow rapidly when power is available, while respecting the ramp rate and other power limitations of the fuel cell and safety limitations of the load. Power flow decreases after an alert indicating an electrical output limitation of the fuel cell. Permitted power flow increases in response to a power demand increase (actual or requested) from the load in the absence of the alert. Power flow may increase or decrease in a fixed amount, a proportional amount, or per a sequence. A power controller relay may trip open on a low fuel cell output voltage or high load current.

A control method of a cooling water pump of fuel cell vehicle is provided. The method includes comparing a derived temperature value, including a cooling water temperature of a fuel cell or an estimated temperature of a stack of the fuel cell, with predetermined temperature criteria and comparing a required output value of the stack of the fuel cell with predetermined output criteria. The cooling water pump is then operated in a normal mode when the derived temperature value is greater than the temperature criteria or when the required output value is greater than the output criteria. Additionally, the cooling water pump is operated in a stop mode when the derived temperature value is less than the temperature criteria and, simultaneously, when the required output value is less than the output criteria.

Charging initiation methods for flow batteries, controllers for flow batteries and flow battery systems are disclosed. A charging initiation method for a flow battery which allows charging of the flow battery from an AC power supply with a power converter having a minimum operational DC voltage is described. Details of the flow battery construction are provided. The charging initiation method so described includes a pre-charging initiation condition that varies depending on a DC voltage threshold or a current threshold.