Emergency power supply system, aircraft having such an emergency power supply system and a method for providing at least electric power and hydraulic power in case of an emergency in an aircraft

An aircraft comprising:

• at least one AC bus;
• at least one hydraulic network;
• and
• at least one emergency power supply system comprising:
• at least one fuel cell having an electric outlet for providing electric power with a DC supply voltage;
• a conversion unit for conversion of electric power, the conversion unit being couplable with the electric outlet of the at least one fuel cell and with at least one of the at least one AC bus and a DC bus of the aircraft;
• and
• at least one hydraulic pump having an electric motor and a motor control electronics unit and being couplable with the at least one hydraulic network of the aircraft for providing hydraulic power,
• wherein the conversion unit is adapted for converting the DC supply voltage of the electric outlet of the at least one fuel cell to at least one of an AC voltage matching a predetermined voltage at the at least one AC bus and a DC voltage matching a predetermined voltage at the DC bus,
• wherein the electric motor is selectively couplable with the at least one fuel cell and the at least one AC bus, wherein the electric motor is adapted for being selectively operated by the supply of electric power either from the at least one fuel cell or the at least one AC bus, wherein a direct current supplied from the at least one fuel cell is converted to an alternating current, and
• wherein the electric motor comprises a stator having a set of interconnected stator windings, the electric motor being configured for changing a connection scheme of the stator windings while maintaining three phases, wherein the connection scheme of the stator windings is selectable from at least two patterns, wherein a first pattern of the at least two patterns enables the electric motor to be operated with a first voltage delivered from the at least one AC bus and wherein a second pattern of the at least two patterns enables the electric motor to be operated with a second voltage delivered by the at least one fuel cell.

A method for providing at least hydraulic power and electric power in an aircraft, the method comprising:

• providing electric power by at least one fuel cell having an electric outlet with a DC supply voltage;
• converting electric power by a conversion unit provided by at least one of an AC bus and a DC bus of the aircraft and the electric outlet of the at least one fuel cell and to at least one of an AC voltage matching a predetermined voltage at the AC bus and a DC voltage matching a predetermined voltage at the DC bus;
• supplying the converted electric power to at least one of the AC bus and the DC bus;
• and
• providing hydraulic power to a hydraulic system of the aircraft by at least one hydraulic pump having an electric motor and a motor control electronics unit,
• converting a direct current supplied from the at least one fuel cell to an alternating current, and
• selectively changing a connection scheme of a set of interconnected stator windings of a stator of the electric motor to a first pattern that enables the electric motor to be operated with a first voltage delivered from the AC bus or to a second pattern that enables the electric motor to be operated with a second voltage delivered by the at least one fuel cell while maintaining three phases.