An air pressure in fuel cells of an electric power generation system comprising a fuel cell stack (PCS) is raised with a pressurized air cooling system with recirculation to values at least two times greater than typical values for an PCS with air cooling. The FCS is either placed in a high-pressure chamber to which air is injected, or air outgoing from the FCS is redirected via a duct back to the FCS inlet and a portion of pressurized fresh air is added thereto. The chamber or the duct is provided with a radiator by means of which circulating air heat is transferred into the external environment. Air recirculation in the chamber or the duct is effected by means of fans for cooling fuel cells. Useful capacity of electric power generation systems based on fuel cells is raised significantly, the necessity of using a humidifier is excluded, and the temperature range of fuel cell operation is expanded.

An energy regulation method for a fuel cell energy supply system including a plurality of fuel cell power generation modules, a plurality of power conversion modules, and a communication control module connected to the plurality of power conversion modules includes: calculating a parameter average value based on an energy state parameter of the fuel cell power generation module; calculating a compensation factor depending on the energy state parameter and the parameter average value; calculating a control parameter reference value of each of the power conversion modules based on a droop algorithm, and multiplying the control parameter reference value by the corresponding compensation factor to obtain a control parameter set value of the power conversion module; and regulating the corresponding fuel cell power generation modules depending on the control parameter set value.

A fuel cell system that generates electric power by supplying anode gas and cathode gas to a fuel cell includes a control valve adapted to control the pressure of the anode gas to be supplied to the fuel cell; a buffer unit adapted to store the anode-off gas to be discharged from the fuel cell; a pulsation operation unit adapted to control the control valve in order to periodically increase and decrease the pressure of the anode gas at a specific width of the pulsation; and a pulsation width correcting unit adapted to correct the width of the pulsation on the basis of the temperature of the buffer unit.

In order to improve estimation accuracy of a purging amount, a fuel cell system comprises a supply valve that controls a supply of an anode gas into an anode system, a purge valve that discharges an off-gas from the anode system, a pressure detecting unit configured to estimate or measures a pressure inside the anode system, and a purging amount estimating unit configured to estimate a purging amount of the off-gas discharged from the anode system through the purge valve based on a pressure change inside the anode system during a purge valve close duration in a supply valve open state and a pressure change inside the anode system during a purge valve close duration in a supply valve close state.

A fuel cell system includes a fuel feeder that supplies fuel, a fuel cell stack that generates power through an electrochemical reaction using air and a hydrogen-containing gas generated from the fuel, a temperature sensor that senses the temperature of the fuel cell stack, and a controller. The fuel cell stack has a membrane electrode assembly including an electrolyte membrane through which protons can pass, a cathode on one side of the electrolyte membrane, and an anode on the other side of the electrolyte membrane. The controller defines an upper limit of current output from the fuel cell stack on the basis of the temperature of the fuel cell stack and the supply of the fuel and keeps the current output from the fuel cell stack at or below the upper limit.

A fuel cell system includes a fuel feeder that supplies fuel, a fuel cell stack that generates power through an electrochemical reaction using air and a hydrogen-containing gas generated from the fuel, a temperature sensor that senses the temperature of the fuel cell stack, and a controller. The fuel cell stack has a membrane electrode assembly including an electrolyte membrane through which protons can pass, a cathode on one side of the electrolyte membrane, and an anode on the other side of the electrolyte membrane. The controller defines an upper limit of current output from the fuel cell stack on the basis of the temperature of the fuel cell stack and the supply of the fuel and keeps the current output from the fuel cell stack at or below the upper limit.

A fuel cell system comprising (i) at least one fuel cell stack (30) comprising at least one intermediate-temperature solid oxide fuel cell, and having an anode inlet (41) and a cathode inlet (61) and (ii) a reformer (70) for reforming a hydrocarbon fuel to a reformate, and a reformer heat exchanger (160); and defining: an anode inlet gas fluid flow path from a fuel source (90) to said reformer (70) to said fuel cell stack anode inlet (41); a cathode inlet gas fluid flow path from an oxidant inlet (140, 140′, 140″) through at least one cathode inlet gas heat exchanger (110, 150) to said reformer heat exchanger (160) to said fuel cell stack cathode inlet (61); wherein said at least one cathode inlet gas heat exchanger (110, 150) is arranged to heat relatively low temperature cathode inlet gas by transfer of heat from at least one of (i) an anode off-gas fluid flow path and (ii) a cathode off-gas fluid flow path; wherein said reformer heat exchanger is arranged for heating said anode inlet gas from said relatively high temperature cathode inlet gas to a temperature T.sub.3 at the anode inlet that is below a temperature T.sub.1 at the cathode inlet; and wherein oxidant flow control means (200) for controlled mixing of low temperature oxidant from the or each oxidant inlet (140, 140′, 140″) with high temperature cathode inlet gas to control a temperature T.sub.1 at the cathode inlet (61) relative to a temperature T.sub.3 at the anode inlet (41) and at a level higher than T.sub.3.

A pressurized air supply system supplies, to a pressurization object device, flowing air that includes at least one of compressed air, which is generated by compressing air supplied from an air supply source, or discharged air from a turbocharger compressor forming a turbocharger. The compressor is controlled such that a saturated steam temperature of the flowing air supplied from the air supply source to the pressurization object device is lower than a temperature in the pressurization object device, at startup.

A pressurized air supply system supplies, to a pressurization object device, flowing air that includes at least one of compressed air, which is generated by compressing air supplied from an air supply source, or discharged air from a turbocharger compressor forming a turbocharger. The compressor is controlled such that a saturated steam temperature of the flowing air supplied from the air supply source to the pressurization object device is lower than a temperature in the pressurization object device, at startup.

A method for operating a fuel cell assembly, the fuel cell assembly including a fuel cell stack having a solid oxide fuel cell, the solid oxide fuel cell having an anode, a cathode, and an electrolyte, the method including: determining a temperature setpoint for the fuel cell stack, for output products of the fuel cell stack, or both; and controlling a volume of oxidant provided to the anode in response to the determined temperature setpoint to control a temperature of the fuel cell stack, a temperature of the output products of the fuel cell stack, or both.