Abstract: A method of controlling power provided by a generator to an end system in which power is diverted from the output of said generator to an auxiliary system during periods of excessive power output from the generator. The diverted power is stored in an energy store and, during periods of lower power output from the generator, is returned to the end system by discharging the energy store. The diversion and return of power is controlled to maintain the power delivered to the end system at a desired mean power level. Diversion of power from the generator also has the effect of preventing the generator from producing excessive voltage levels.

Abstract: A displacement system for a submersible electrical system such as a tidal turbine system, the displacement system comprising a base for the turbine or related electrical components, a vessel having a buoyant body and at least three rigid legs each displaceable relative to the body between a raised and a lowered position, and in which the base is adapted to be secured to and displaceable by the three legs in order to allow the base to be deployed or retrieved from the seabed using the legs, which legs can also be utilised to raise the body of the vessel out of the water to provide a stable work platform above the deployment site.

Abstract: The present invention provides an adaptive hydroelectric turbine system comprising a base for a hydroelectric turbine or other electrical component, the base having four ground contacting feet, at least one of which is displaceable relative to the remaining of the base such as to ensure that all four feet can contact the seabed to provide improved stability and load bearing capabilities.

Abstract: The present invention provides a hydroelectric turbine for generating electricity by extracting power from the tidal flow of water through the turbine, the turbine comprising a shaftless rotor which results in the eccentric rotation of the rotor relative to the stator, which can result in uneven generation of power through differences in the spacing between rim mounted magnets and coils forming a generator of the turbine, the turbine thus employing groupings of equally spaced and serially connected coils.

Abstract: The present invention relates to a hydroelectric turbine recovery system, and in particular a system which significantly reduces the complexity of recovering a base mounted hydroelectric turbine from a deployment site on the seabed by providing a frame having an open mouth which can be advanced around the turbine before the frame is fully lowered into locking engagement with the base, thereby allowing the base, with the turbine thereon, to be recovered from the seabed.

Abstract: A control system for controlling an operation of a hydroelectric turbine. The control system comprises a converter system to convert AC power, supplied by a generator connected to the turbine, and having a voltage and frequency that is a function of a rotational speed of the turbine, to AC power having a voltage and frequency of a transmission system for transmitting the AC power to a receiving station. The system further comprises a control unit that is arranged to co-operate with the converter system to adjust the AC voltage supplied by the generator in response to a water flow speed through the turbine to thereby control rotation of the turbine. The converter system comprises a first-stage converter and a second-stage converter, with a DC link provided between the first and second-stage converters. The first-stage converter is arranged to convert the AC power supplied by the generator to DC power.

Abstract: A hydroelectric turbine array system comprises an array of turbine systems and a supervisory controller. Each turbine system of the array comprises a hydroelectric turbine and a control system. The control system includes a converter system arranged to convert AC power, supplied by a generator connected to the hydroelectric turbine and having a voltage and frequency that is a function of a rotational speed of the hydroelectric turbine, to AC power having a voltage and frequency of a transmission system for transmitting the AC power to a receiving station and a control unit co-operable with the converter system to adjust the AC voltage supplied by the generator.

Abstract: The present invention is concerned with a method of transporting a hydroelectric turbine system, and a vessel suitable for use in implementing said method, whereby the vessel comprises a raised or raisable section, which enables the vessel to pass over a portion of a base of the hydroelectric turbine system, when located in a flooded dry dock, which portion of the base projects above the water line in the dock.

Abstract: An electrical machine comprising a stator and a member arranged to move relative to said stator. The stator comprises a first stator structure incorporating a first plurality of windings disposed along the direction of relative motion and displaced from the movable member in a direction perpendicular to the direction of motion, and a second stator structure incorporating a second plurality of windings displaced in a second direction from the movable member, so that the movable member lies between the two stator structures. The movable member is arranged to electrically couple with the windings. The first plurality of windings includes a single phase winding connected to a first single-phase ac supply, and the second plurality of windings includes a single phase winding of the same pole pitch being displaced in the direction of relative motion from first plurality of windings and connected to a second single-phase ac supply whose phase is displaced from that of the first supply.

Abstract: A power generator for a hydro turbine is axially coupled to the hydro turbine. The generator comprises a rotor arranged to rotate about an axis in response to fluid flow through said turbine. A first stator structure incorporates at least a first winding disposed circumferentially around the axis and axially displaced in a first inboard direction from the rotor. A second stator structure incorporates a least a second winding disposed circumferentially around the axis and axially displaced in a second outboard direction from the rotor, the rotor being arranged to electrically couple with the windings.

Abstract: A control system for controlling an operation of a hydroelectric turbine. The control system comprises a converter system to convert AC power, supplied by a generator connected to the turbine, and having a voltage and frequency that is a function of a rotational speed of the turbine, to AC power having a voltage and frequency of a transmission system for transmitting the AC power to a receiving station. The system further comprises a control unit that is arranged to co-operate with the converter system to adjust the AC voltage supplied by the generator in response to a water flow speed through the turbine to thereby control rotation of the turbine. The converter system comprises a first-stage converter and a second-stage converter, with a DC link provided between the first and second-stage converters. The first-stage converter is arranged to convert the AC power supplied by the generator to DC power.

Abstract: A system and method for electrical power conversion, with the system being intended for use in converting a high voltage DC power output from a turbine generator to an AC power signal that is suitable for connecting to an AC power grid. The system utilizes a mechanical coupling between a synchronous motor driving a synchronous generator in order to provide isolation, as well as allowing for control of the real power output by the system.

Abstract: A method of controlling power provided by a generator to an end system in which power is diverted from the output of said generator to an auxiliary system during periods of excessive power output from the generator. The diverted power is stored in an energy store and, during periods of lower power output from the generator, is returned to the end system by discharging the energy store. The diversion and return of power is controlled to maintain the power delivered to the end system at a desired mean power level. Diversion of power from the generator also has the effect of preventing the generator from producing excessive voltage levels.

Abstract: A method of controlling power provided by a generator to an end system in which power is diverted from the output of said generator to an auxiliary system during periods of excessive power output from the generator. The diverted power is stored in an energy store and, during periods of lower power output from the generator, is returned to the end system by discharging the energy store. The diversion and return of power is controlled to maintain the power delivered to the end system at a desired mean power level. Diversion of power from the generator also has the effect of preventing the generator from producing excessive voltage levels.

Abstract: A method of testing a hydroelectric turbine before the turbine is installed and secured on the seabed, in order to ensure that the turbine is operating as expected, the method involving securing the turbine to a vessel and displacing the vessel through water in order to effect rotation while monitoring one or more operating parameters of the turbine.

Abstract: The present invention provides a hydroelectric turbine system comprising an array of turbines in series and a cabling system for use in connecting together adjacent turbines in the array, the cabling system being designed to allow the majority of the cabling connecting adjacent turbines to be laid substantially in line with the direction of tidal flow in order to reduce stress on the cabling system when the turbines are deployed on the seabed at sites of high tidal flow.

Abstract: An electrical machine comprising a stator and a member arranged to move relative to said stator. The stator comprises a first stator structure incorporating a first plurality of windings disposed along the direction of relative motion and displaced from the movable member in a direction perpendicular to the direction of motion, and a second stator structure incorporating a second plurality of windings displaced in a second direction from the movable member, so that the movable member lies between the two stator structures. The movable member is arranged to electrically couple with the windings. The first plurality of windings includes a single phase winding connected to a first single-phase ac supply, and the second plurality of windings includes a single phase winding of the same pole pitch being displaced in the direction of relative motion from first plurality of windings and connected to a second single-phase ac supply whose phase is displaced from that of the first supply.

Abstract: According to the present invention there is provided a hydroelectric turbine system comprising a base comprising a frame, and a plurality of legs extending from the frame, the base being provided with one or more load bearing members in the form of outriggers extending from the base at a position adapted to resist, in use, overturning of the base, in particular during extreme tidal conditions.

Abstract: A method of installing an off-shore tidal hydroelectric turbine generator is described. The method provides for a number of safety features, ensuring that all components are safe to handle during the installation operation, and also ensuring that the turbine will not start spinning during the installation operation.