A power net system of a fuel cell vehicle is provided. The power net system includes a fuel cell and a high-voltage battery unit connected in parallel via a main bus and a first switching unit that is configured to form and block an electrical connection between an output terminal of the fuel cell and the main bus. A load device diverges and is connected between the output terminal of the fuel cell and the first switching unit. A reverse current blocking unit is connected between the first switching unit and a node from which the load device diverges. A second switching unit is configured to form and block an electrical connection between the output terminal of the fuel cell and the load device. A controller operates the first and second switching units and adjusts the electrical connection state between the main bus and the high-voltage battery unit.

A method and a system for controlling startup of a fuel cell are provided. The method includes sensing a startup request signal and boosting a Bi-directional high-voltage DC/DC Converter (BHDC) of a main bus stage when the startup request signal has been sensed by a controller. A valve of an air/hydrogen line is then opened together with the boosting of the BHDC and the startup of the fuel cell is completed by allowing an output of the fuel cell after the valve of the air/hydrogen line is opened.

A drive system includes a drive device including an electric power generator; a fuel cell; a secondary battery; a fuel cell step-up converter including a diode; a relay connected to wiring between the fuel cell step-up converter and the drive device; a secondary battery step-up converter connected; a fuel cell voltage sensor; a secondary battery voltage sensor; and a controller. The controller stops the secondary battery step-up converter when a short-circuit fault of the diode is detected, disconnects the relay when a voltage of the fuel cell is higher than a voltage of the secondary battery after stopping the secondary battery step-up converter, and when the voltage of the secondary battery is higher than or equal to the voltage of the fuel cell, executes a voltage control process which increases the voltage of the fuel cell relative to the voltage of the secondary battery, and disconnects the relay.

A fuel cell module has a hydrogen recirculation pump and a controller. The controller receives a signal indicating the response of the pump to changes in the density or humidity of gasses in the hydrogen recirculation loop. The controller is programmed to consider the signal in controlling one or more balance of plant elements that effect the removal of water from the stack. In a process for operating the fuel cell module, the signal is considered when controlling one or more balance of plant elements that effect the removal of water from the stack. For example, an increase in current drawn from a constant speed or voltage recirculation pump indicates an increase in humidity and suggests that water should be removed from the stack, for example by increasing a coolant temperature set point.

A drive system includes a drive device including an electric power generator; a fuel cell; a secondary battery; a fuel cell step-up converter including a diode; a relay connected to wiring between the fuel cell step-up converter and the drive device; a secondary battery step-up converter connected; a fuel cell voltage sensor; a secondary battery voltage sensor; and a controller. The controller stops the secondary battery step-up converter when a short-circuit fault of the diode is detected, disconnects the relay when a voltage of the fuel cell is higher than a voltage of the secondary battery after stopping the secondary battery step-up converter, and when the voltage of the secondary battery is higher than or equal to the voltage of the fuel cell, executes a voltage control process which increases the voltage of the fuel cell relative to the voltage of the secondary battery, and disconnects the relay.

A motor drive control method is provided for controlling a speed of a motor such that a measured speed value of the motor follows a speed command value. The motor drive control method includes an on/off driving operation of driving a torque of the motor based on the speed command value in such a way that the torque of the motor is repeatedly turned on/off on preset cycle and duty. The motor drive control method and system can markedly enhance efficiency of a motor by reducing switching loss and current ripple loss of an inverter in a low-speed driving period of a high-speed motor.

Ways of controlling a fuel cell and a battery are provided that include controlling a current of the battery using a current of the fuel cell and where a target battery state of charge is controlled using an actual state of charge of the battery. Systems and methods may employ an inner loop controller and an outer loop controller. The inner loop controller may be configured to control current of the battery using current of the fuel cell, where the inner loop controller includes an integrating controller operating on a time-averaged basis. The outer loop controller may be configured to control a target battery state of charge using an actual state of charge of the battery, where the outer loop controller includes a proportional controller operating using continuous modulation.

A compressor system is provided for a fuel cell system having at least one compressor stage with an electric motor. The compressor stage is set up to suck in and compress an air mass flow along a fluid path using the motor and to discharge the compressed air mass flow as a reactant feed. The compressor system also has a control unit configured to determine a current for supplying the electric motor and a rotational speed of the electric motor or a frequency of the current of the electric motor. In addition, the control unit is configured to ascertain a theoretical air mass flow value in the fluid path as a function of the current and the speed or as a function of the current and the frequency, and to control the motor as a function of the theoretical air mass flow value.

There is provided a fuel cell mounting structure including (i) a fuel cell which is configured to be disposed in a vehicle where a drive motor that drives rear wheels is placed in a vehicle rear portion, the fuel cell placed on the vehicle upper side of a suspension member disposed in a vehicle front portion and connected via a plurality of anti-vibration members to the suspension member, and (ii) auxiliaries that are attached to the fuel cell in a state in which the auxiliaries do not contact the suspension member and include at least an air compressor and a pump.

A reliable, end-to-end power supply solution for components of a telecommunications network provides either a primary source or a backup source of electrical power at various telecommunications sites for reliable operation of telecommunications equipment. One subsystem of the power supply solution includes one or more proton exchange membrane type fuel cells and an energy storage device for storing DC electrical power produced by the fuel cells. Another subsystem includes one or more microturbine generators, one or more rectifiers for converting AC electrical power produced by the microturbine generators to DC electrical power, and one or more proton exchange membrane type fuel cells for producing DC electrical power. The power supply solution ensures that voice and data traffic is reliably handled by a telecommunications network in situations where commercial electric utilities fail to supply power at certain points along the network.