Abstract: A vehicle includes: a prime mover; a hydraulic fluid manifold; a hydraulic machine; a hydraulic accumulator; one or more hydraulic actuators; a valve arrangement; and a controller. The controller is configured to receive an actuator demand signal indicative of a demand to move the one or more hydraulic actuators; and to control the hydraulic machine and the valve arrangement to cause movement of the one or more actuators in accordance with the actuator demand signal by bringing the hydraulic accumulator into fluid communication with a first actuator chamber of the one or more hydraulic actuators, and to synchronise therewith changing a pressure in a second actuator chamber of the one or more hydraulic actuators. The second actuator chamber is in fluid communication with the hydraulic machine.

Abstract: A hydraulic apparatus including an electronically commutated machine having a plurality of working chambers which are controlled on each cycle of working chamber volume to carry out active or inactive cycles of working chamber volume allows only a plurality of defined fractions of cycles to be active cycles to avoid generating frequencies of active cycles which cause low frequency resonances. The demand signal may be quantised into fractions m/n where n is an integer below a threshold selected to avoid repeating patterns of active cycles of more than a cut-off length.

Abstract: A hydraulic transmission comprising a variable displacement pump and motor, at least one having cylinders having valves which are controllable on each cycle of cylinder working volume to determine the net displacement of working fluid by the cylinder. The transmission has a valve control module which determines a displacement of the pump and the motor by specifying a displacement demand. The pump and/or motor valve control module determine the frequency of intensity peaks in the frequency spectrum of the pattern of cylinders carrying out active and inactive cycles of cylinder working volume using a first procedure and, if these will fall within disallowed frequency bands including the resonant frequency of components with which the transmission is in mechanical communication, the displacement demand, or another input, is periodically modified to suppress generation of those frequencies. The hydraulic transmission is useful for example in a wind turbine generator, or a vehicle.

Abstract: A hydraulic transmission comprising a variable displacement pump and motor, at least one having cylinders having valves which are controllable on each cycle of cylinder working volume to determine the net displacement of working fluid by the cylinder. The transmission has a valve control module which determines a displacement of the pump and the motor by specifying a displacement demand. The pump and/or motor valve control module determine the frequency of intensity peaks in the frequency spectrum of the pattern of cylinders carrying out active and inactive cycles of cylinder working volume using a first procedure and, if these will fall within disallowed frequency bands including the resonant frequency of components with which the transmission is in mechanical communication, the displacement demand, or another input, is periodically modified to suppress generation of those frequencies. The hydraulic transmission is useful for example in a wind turbine generator, or a vehicle.

Abstract: It is intended to provide a power generating apparatus of renewable energy type which obtains desired torque rapidly in response to changes of the renewable energy as well as a method of operation such an apparatus.

Abstract: In view of the problems above, it is an object of the present invention is to provide a power generating apparatus of renewable energy type which can achieve a desired output of the hydraulic motor and a stable power generation regardless of changes of the renewable energy as well as a method of operation such an apparatus.

Abstract: An object of the present invention is to provide a wind turbine generator system and an operation control method thereof, which has a superior operation efficiency and stability at a low wind speed and during the occurrence of a gust and is equipped with Ride Through function at Grid low voltage condition. The wind turbine generator comprises a hydraulic pump of a variable displacement type which is rotated by the main shaft, a hydraulic motor of a variable displacement type which is connected to the generator, and a high pressure oil line and a low pressure oil line which are arranged between the hydraulic pump and the hydraulic motor. An accumulator is connected to the high pressure oil line via an accumulator valve. ACC valve control unit controls opening and closing of the accumulator valve based on at least one of wind speed and the state of the grid.

Abstract: A wind turbine generator (100), or other energy extraction device, has a hydraulic circuit comprising a hydraulic pump (129) driven by a rotating shaft (125) and a hydraulic motor (131) driving an electricity generator (157), or other load. A high pressure manifold (133) extending between the pump and motor is in communication with an accumulator (145, 147, 149). A controller receives a control signal and regulates the displacement of working fluid by the hydraulic pump and the hydraulic motor relative to each other. Thus, power input through the rotating shaft and output to the load can be decoupled for at least a period of time and the energy output of energy extraction device can be varied, for example to smooth the total power output to an electricity grid (101), without compromising power input. A group of energy extraction devices can be controlled in concert to maximise power input while providing smooth power output.

Abstract: It is intended to provide a power generating apparatus of renewable energy type and an operation method of the power generating apparatus, which can achieve both variable speed operation and grid connection without a frequency converting circuit and which uses a hydraulic transmission. In the power generating apparatus of renewable energy type 1, renewable energy received via a blade 4 is transmitted to a synchronous generator 20 via a rotating shaft 8 and a hydraulic transmission 10. The synchronous generator 20 is driven by a hydraulic motor 14 of the hydraulic transmission 10 to generate power. The synchronous generator 20 is connected to a grid without a frequency converting circuit and the power generated by the synchronous generator 20 is supplied to the grid 50. The power generating apparatus 1 is also provided with a transmission controller 40 which controls the hydraulic transmission 10.

Abstract: A hydraulic machine in which the volume of working fluid displaced by each cylinder is selectable on each cycle of working chamber volume by active control of one or more electronic valves has a controller configured to select specified groups of cylinders to repetitively carry out active cycles until a change in selection is made. The groups are selected to reduce torque ripple and/or bearing side load. The cam profile may be varied to further reduce torque ripple.

Abstract: An object of the invention is to provide a wind turbine generator or a tidal current generator which is equipped with a hydraulic transmission and achieves a superior power generation efficiency, and a operation method thereof. The wind turbine generator 1 comprises a hydraulic pump 12 of a variable displacement type which is rotated by the main shaft 8, a hydraulic motor 14 of a variable displacement type which is connected to the generator 20, and a high pressure oil line 16 and a low pressure oil line 18 which are arranged between the hydraulic pump 12 and the hydraulic motor 14. The pump controller 32 obtains a target torque of the hydraulic pump 12 at which a power coefficient becomes maximum, and then sets a displacement Dp of the hydraulic pump 12 based on the target torque and the pressure in the high pressure oil line 16.

Abstract: A power generating apparatus includes a rotating shaft, a hydraulic pump driven by the rotating shaft, a hydraulic motor driven by pressurized oil supplied from the hydraulic pump, and a generator coupled to the hydraulic motor. Each of the hydraulic pump and motor includes working chambers each defined by a cylinder and a piston, a high pressure manifold and a low pressure manifold. Each of the high and low pressure manifolds includes branch channels connected to the working chambers and a merging channel connected to a high or low pressure oil line. The branch channels are equipped with high or low pressures valves, joined together and merged into the merging channel.

Abstract: A wind turbine generator includes a hydraulic pump rotatable by a main shaft, a hydraulic motor connected to a generator, and a high pressure oil line and a low pressure oil line which are arranged between a hydraulic pump and a hydraulic motor. An operation mode selection unit switches an operation mode between a normal operation mode and a low rotation speed operation mode depending on environment conditions. The low rotation speed operation mode has a rated rotation speed of the main shaft lower than that of the normal operation mode, at least one of a rated displacement of the hydraulic pump and a rated pressure of the high pressure oil line that are greater than that of the normal operation mode and a rated output of a generator substantially same as that of the normal operation mode.

Abstract: A wind turbine generator, or other energy extraction device, has a hydraulic circuit comprising a hydraulic pump driven by a rotating shaft and a hydraulic motor driving an electricity generator. When the electricity generator is switched off, it executes one or more pumping cycles to pressurise the high pressure manifold and therefore recover angular kinetic energy from the electricity generator rotor which can later be used to reaccelerate the electricity generator rotor to the correct operating speed for an electricity grid. Overall energy efficiency is increased and the minimum operating high pressure manifold pressure may be reduced as a result.

Abstract: An object of the invention is to provide a wind turbine generator or a tidal current generator which is equipped with a hydraulic transmission and achieves a superior power generation efficiency, and a operation method thereof. The wind turbine generator 1 comprises a hydraulic pump 12 of a variable displacement type which is rotated by the main shaft 8, a hydraulic motor 14 of a variable displacement type which is connected to the generator 20, and a high pressure oil line 16 and a low pressure oil line 18 which are arranged between the hydraulic pump 12 and the hydraulic motor 14. The pump controller 32 obtains a target torque of the hydraulic pump 12 at which a power coefficient becomes maximum, and then sets a displacement Dp of the hydraulic pump 12 based on the target torque and the pressure in the high pressure oil line 16.

Abstract: An object of the present invention is to provide a wind turbine generator and an operation control method thereof, which takes measures against issues such as noise, bird strike and a friction heat of a bearing shaft. The wind turbine generator 1 comprises a hydraulic pump 12 of a variable displacement type which is rotated by the main shaft 8, a hydraulic motor 14 of a variable displacement type which is connected to the generator 20, and a high pressure oil line 16 and a low pressure oil line 18 which are arranged between the hydraulic pump 12 and the hydraulic motor 14. An operation mode selection unit 38 switches an operation mode between a normal operation mode and a low rotation speed operation mode.