Abstract: A marine power system including multiple of fuel cells, multiple of D C/AC converters and at least one propulsion motor. In the marine power system, each fuel cell of the multiple of fuel cells is connectable to an input of a DC/AC converter of the multiple of DC/AC converters and at least one group of multiple of DC/AC converters is connectable to the at least one propulsion motor to provide variable frequency and amplitude voltage to the at least one propulsion motor. Further, at least one of the multiple of DC/AC converters is connectable to a fixed frequency AC bus to provide voltage with a fixed frequency and amplitude to the fixed frequency AC bus.

Abstract: A fuel cell power system and a method of starting a fuel cell power system. The fuel cell power system includes a fuel cell system having one or more voltage outputs, one or more DC/DC converters each having an output and an input, the input being connectable to the voltage outputs of the fuel cell system, a DC voltage link connectable to the output of the one or more DC/DC converters, and a local load connectable to the DC voltage link. In the system, the local load is adapted to draw power from the fuel cell system to decrease the voltage of the fuel cell system.

Abstract: A DC voltage distribution arrangement and method of controlling a DC voltage distribution system, the DC voltage distribution system including a DC voltage bus, a fuel cell electrically connected to the DC voltage bus, an energy storage and an energy storage converter, wherein the input of the energy storage converter is connected to the energy storage and the output of the energy storage converter is connected to the DC bus. The method comprises providing a DC voltage reference for the energy storage converter, the energy storage converter controlling the voltage of the DC voltage bus by providing power from the energy storage or to the energy storage, detecting power flow of the energy storage converter, and changing the DC voltage reference on the basis of the detected power flow to change the power taken from the fuel cell.

Abstract: A marine power system including multiple of fuel cells, multiple of D C/AC converters and at least one propulsion motor. In the marine power system, each fuel cell of the multiple of fuel cells is connectable to an input of a DC/AC converter of the multiple of DC/AC converters and at least one group of multiple of DC/AC converters is connectable to the at least one propulsion motor to provide variable frequency and amplitude voltage to the at least one propulsion motor. Further, at least one of the multiple of DC/AC converters is connectable to a fixed frequency AC bus to provide voltage with a fixed frequency and amplitude to the fixed frequency AC bus.

Abstract: An electric power generation system and a method in an electric power generation system.

Abstract: A DC voltage distribution arrangement and method of controlling a DC voltage distribution system, the DC voltage distribution system including a DC voltage bus, a fuel cell electrically connected to the DC voltage bus, an energy storage and an energy storage converter, wherein the input of the energy storage converter is connected to the energy storage and the output of the energy storage converter is connected to the DC bus. The method comprises providing a DC voltage reference for the energy storage converter, the energy storage converter controlling the voltage of the DC voltage bus by providing power from the energy storage or to the energy storage, detecting power flow of the energy storage converter, and changing the DC voltage reference on the basis of the detected power flow to change the power taken from the fuel cell.

Abstract: An electric power generation system and a method in an electric power generation system.

Abstract: An arrangement is disclosed for supplying propulsion power to a contra rotating propellers (CRP) propulsion system in a marine vessel, which arrangement can include a first propeller driven by a rotating power unit, and a second propeller driven by an AC motor. The second propeller can be rotated in an opposite direction relative to the first propeller, wherein an AC generator is driven by the rotating power unit and the AC generator is electrically connected to the AC motor. The rotation speed of the second propeller is between for example 95% and 150% of the rotation speed of the first propeller. The AC motor and the AC generator have the same electrical frequency. The pole number of the AC generator is from for example 2 to 40 and the pole number of the AC motor is from for example 2 to 40.

Abstract: An arrangement is disclosed for supplying electric power to a propulsion system of a marine vessel having a propeller motor, which is connected to an AC generator. The AC generator supplies electric energy to the propeller motor. The AC generator is rotated by a rotating power unit. A frequency converter is electrically connectable in parallel to the AC generator and the frequency converter supplies electric power from a second power unit.