A power conditioning system includes a fuel cell connected to a load, a fuel cell converter connected between the fuel cell and the load and converting an output voltage of the fuel cell at a predetermined required voltage ratio, a battery connected to the load in parallel to the fuel cell and serving as a power supply source different from the fuel cell, and a battery converter connected between the battery and the load and converting an output voltage of the battery at a predetermined required voltage ratio. The power conditioning system includes a current bypass path configured to couple the fuel cell and the load while bypassing the fuel cell converter, an alternating-current voltage application unit configured to apply an alternating-current voltage signal to an output side of the fuel cell converter, and an internal state estimation unit configured to estimate an internal state of the fuel cell on the basis of a predetermined physical quantity when the alternating-current voltage signal was applied by the alternating-current voltage application unit.

A power supply device includes a power supply, a conversion unit performing voltage conversion on electric power to be supplied from the power supply, and a control unit generating a first control signal for inputting or outputting a target voltage or a target current to and from the conversion unit by a feedback loop, and controlling the conversion unit based on the first control signal and a second control signal for detecting a state of the power supply, generated outside the feedback loop. The control unit sets a specific parameter of the second control signal based on a feedforward term based on the output of the power supply and a feedback term in which the specific parameter included in at least one of electric power output from the power supply and input into the conversion unit and electric power output from the conversion unit, is a feedback component.

A fuel cell system that includes a fuel cell body that is formed by a membrane electrode assembly including an anode catalyst and a cathode catalyst between which an electrolyte membrane is sandwiched and a pair of separators forming an anode-catalyst-side flow channel and a cathode-catalyst-side flow channel, a fuel supply system configured to supply fuel gas to the fuel cell body, an oxidant supply system configured to supply oxidant gas to the fuel cell body, a control device that controls these supply systems in accordance with an operating state of the fuel cell system and a catalyst deterioration recovery device that recovers deterioration of the anode catalyst. The catalyst deterioration recovery device includes a plurality of catalyst deterioration recovery means, a specific operating state detecting means configured to detect a specific operating state of the fuel cell system and a selecting means configured to selectively activate the plurality of catalyst deterioration recovery means in accordance with the specific operating state.

A control apparatus for a vehicle plant, which is capable of reducing computational load and a storage capacity in a case where the vehicle plant is controlled using a plurality of periodic function values having a plurality of frequencies different from each other. A control apparatus for a fuel cell device includes a first ECU and a second ECU. The second ECU calculates a superposition sine wave value of one of frequencies Z to nZ (Hz) based on a frequency command value by a thinning method using a data group of one set of reference sine wave values, stored in a map. The second ECU executes an AC superposition control using the superposition sine wave value, and calculates impedance of the fuel cell device during execution of the AC superposition control. The first ECU executes an FC humidification control process such that the impedance becomes equal to a target value.

A method for calculating voltage loss of a fuel cell is provided. The method includes sensing an open circuit voltage that is generated in a stack when the switch is opened and detecting an operation voltage and an operation current that are generated in the stack when the switch is closed. A first change graph of voltage data over time is calculated using the voltage data and current data from a time when the switch is opened in a state where the switch is closed. A first voltage of a point at which a trend line for an interval where the voltage data linearly varies with the time meets the first change graph is sensed and then an ohmic resistance voltage loss is calculated using a difference between the first voltage and the operation voltage.

A technique of diagnosing a fuel cell stack is provided. In particular, current and voltage of a fuel cell stack are measured during driving of a fuel cell vehicle and the current and voltage are sequentially stored. It is then determined based on the stored current whether the vehicle is being operated at constant current. Different factors are analyzed depending on whether the vehicle is being operated at constant current, and then it is determined whether the fuel cell stack is in a normal state. A moisture supply into the fuel cell stack is calculated if it is determined that the fuel cell stack is not in the normal state. Based on the calculated moisture supply, whether the fuel cell stack is in a dryout state is diagnosed.

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.

A system for measuring the insulation resistance of a fuel cell vehicle is provided. The system includes a fuel cell that supplies power, a rechargeable high-voltage battery, and a bidirectional converter, disposed between an output terminal of the fuel cell and the high-voltage battery, to adjust a voltage at the output terminal of the fuel cell. A fast measurement unit measures the insulation resistance of the fuel cell vehicle by being connected to the output terminal of the fuel cell and a second measurement unit measures the insulation resistance of the fuel cell vehicle by being connected to the output terminal of the high-voltage battery. A controller operates the bidirectional converter based on the state of the fuel cell vehicle and measure the insulation resistance of the fuel cell vehicle using the first measurement unit or the second measurement unit.

An apparatus includes a stack voltage monitor that measures a voltage of each channel of a plurality of channels of a fuel cell stack. Each of the channel of the plurality of channels includes a predetermined number of unit cells. The stack voltage monitor calculates impedance of each of the channel from the measured voltage. The apparatus further includes a controller that diagnoses a state of the fuel cell stack based on the impedance of each of the channel.

A method for controlling a fuel cell system includes (i) performing a low-temperature start-up process of the fuel cell system, (ii) monitoring internal resistance of a fuel cell stack in the fuel cell system, and (iii) determining that the low-temperature start-up process of the fuel cell system is abnormal based on the appearance of an inflection point in the internal resistance of the monitored fuel cell stack.