Low frequency power is transmitted over long distances from a surface power supply to a subsea rotating machine, such as a pump or compressor. The low frequency power is used to rotate a motor at low speed. A liquid filled magnetic step-up gear module might be used to increase the low speed motor shaft to a higher speed output shaft that can be used to operate the rotating machine. The magnetic gear module can be configured as a fixed ratio, and the surface power supply can be configured to adjust the power frequency to change the speed of a single subsea rotating machine. In other embodiments, the magnetic gear module can provide a variable gear ratio. A fixed low frequency might be transmitted from the surface and multiple subsea loads can be operated from the same power source, each having their own variable magnetic gear module.

Systems and methods for controlling operation of a power converter based on grid conditions are provided. In particular, a first gating voltage can be applied to a switching element of a power converter associated with a wind-driven power generation system. The first gating voltage can be greater than a threshold voltage for the switching element. A grid event associated with an electrical grid coupled to the power generation system can be detected. A second gating voltage can be applied to the gate of the switching element during the detected grid event. The second gating voltage can be greater than the first gating voltage.

A method of maintaining an offshore power plant. A power generating craft is attached to a tow cable on a floating vessel. The floating vessel is moved to an offshore power generating site. The power generating craft is maintained in an airborne state while the floating vessel is moving to the offshore power generating site. The power generating craft is detached from the tow cable and attached to a first end of a tether line at the offshore power generating site. The second end of the tether line is anchored to an underwater floor. The power generating craft is operated in an airborne state.

A method of generating power. An airborne power generating craft is connected to an anchor using a tether line. The anchor is secured to an underwater floor. Power is generated based on movement of the airborne power generating craft in response to a wind force. The tether line is maintained at a constant length between the airborne power generating craft and the anchor as the airborne power generating craft moves in response to the wind force. The airborne power generating craft is connected to an electrical transmission system through at least part of the tether line. The generated power is transmitted to the electrical transmission system. A condition is sensed in which transmitting power to the electrical transmission system is not desired. The airborne power generating craft is electrically isolated to prevent power from being transmitted from the airborne power generating craft to the electrical transmission system.

The present invention relates to a method for operating a power generating assembly in the event of a fault, wherein the power generating assembly comprises a PMG comprising at least first and second sets of stator windings, wherein each set of stator windings is connected to a power converter via a controllable circuit breaker, the method comprising the steps of detecting a fault associated with the first set of stator windings, and lowering, such as interrupting, the current in the second set of stator windings, and, after a predetermined delay, lowering, such as interrupting, the current in the first set of stator windings. The present invention also relates to a power generating assembly being capable of handling such faults, and a wind turbine generator comprising such a power generating assembly.

A system for assembling a generator, preferably a permanently excited generator of a wind turbine, comprising a rotor and a stator. A vertical assembly device connectable to the rotor and the stator is proposed, for guiding the rotor in parallel and coaxially aligned to the stator during assembly, the vertical assembly device comprising a first assembly element being connectable to the rotor, a second assembly element being connectable to the stator, and guiding means for guiding the first assembly element coaxially aligned to the second assembly element.

A stator assembly includes a stator frame structure having an outer annular frame with an outer edge running around a center axis; a plurality of stator segments mounted at the outer edge along a circumferential direction of the outer edge, each stator segment comprising at least one electric coil; and a wiring arrangement electrically connecting the stator segments with an electric power interface. The wiring arrangement comprises a plurality of wiring assemblies, each wiring assembly electrically connecting one of the plurality of stator segments with the power interface is provided. Each wiring assembly is routed along and next to the outer annular frame and comprises electric cables connected in between the electric interface and the respective stator segment, wherein the electric cables are provided with electric insulation structures each surrounding one of the electric cables. Further described is an electric generator and a wind turbine with such a stator assembly.

A ram air turbine having: a strut assembly having an outer housing enclosing a first inner chamber; a generator housing operatively connected to the strut assembly, the generator housing having an outer surface enclosing a second inner chamber, the second inner chamber being fluidly connected to first inner chamber; a turbine assembly operably connected to the strut assembly, the turbine assembly in operation rotates in freestream air; and a power generation device mechanically connected to the turbine assembly and located within the second inner chamber, the power generation device generates power as turbine assembly rotates. The strut assembly includes a first screen portion having a plurality of inlet holes integrally formed in the outer housing. The generator housing includes a second screen portion having a plurality of outlet holes integrally formed in the outer surface. Freestream air passes through inlet holes, over the power generation device, and out outlet holes.

A method for controlling a converter, preferably a generator-side active rectifier of a power converter of a wind power installation, comprising: specifying a target value for the converter; specifying a carrier signal for the converter; capturing an actual value; determining a distortion variable from the target value and the actual value; and determining driver signals for the converter on the basis of the distortion variable and the carrier signal.

A method of mitigating high frequency harmonics in an output current of an electrical power system connected to a power grid includes providing an active harmonic filter in a stator power path connecting a stator of the generator to the power grid. Further, the method includes controlling, via a controller, the active harmonic filter to selectively extract a high frequency harmonic component from the output current. The method also includes determining, via the controller, whether the high frequency harmonic component is a positive sequence harmonic or a negative sequence harmonic. Moreover, the method includes compensating, via the controller, for the high frequency harmonic component based on whether the high frequency harmonic component is the positive sequence harmonic or the negative sequence harmonic to mitigate the high frequency harmonics in the output current.