There is provided methods and systems for controlling a multi-rotor wind turbine generator having at least two rotor nacelle assemblies mounted to a support arrangement by a common yaw control system and each having a wind direction sensor mounted thereto configured to measure a wind direction relative to forward direction of its rotor nacelle assembly. The methods comprise the steps of measuring, for each rotor nacelle assembly, wind power parameter data over a plurality of relative wind directions, determining, based on the measured data, an optimum relative wind direction, either based on the average of two directions at which the parameter is maximum or on a combined data set, and controlling the yaw system accordingly.

A multirotor wind turbine comprising a tower, a suspension arm, a nacelle, and a rotor carried by the nacelle and configured to rotate about a rotor axis to drive a drive train in the nacelle, wherein the tower holds the suspension arm, and the suspension arm holds the nacelle. To facilitate safer and better access to the nacelle or drive train, the suspension arm is configured as a platform to provide support for personnel e.g. during maintenance and repair of the nacelle.

A vertical axis turbine having a first rotor and at least one second rotor, the first rotor being configured to rotate around a first rotation axis that is vertical or more vertical than horizontal. The first rotor may be configured to be driven and/or rotated by wind or water flow. The at least one second rotor is provided on or coupled to the first rotor such that the first rotor is operable to move the second rotor upon rotation of the first rotor. The second rotor is operable to drive a power take off system. Each second rotor rotates around a respective second rotation axis that may be angled or perpendicular to the first rotation axis of the first rotor. The first and second rotors are configured so that the power take-off system can be driven without the need for a gearbox.

A turbine of a power generating system includes a rotary shaft, blades, stoppers and elastic members. Each of the blades includes a connecting side and an active side opposite to the connecting side, and the blades are disposed on the rotary shaft at intervals by a predetermined distance, in which the blades are pivotally connected to the rotary shaft through the connecting sides. The stoppers respectively correspond to the blades and are disposed over the rotary shaft for limiting expansion angles of the blades. Each of the elastic members includes a fixed end and a moving end opposite to the fixed end, and the fixed ends attach to the rotary shaft, and the moving ends respectively attach to the blades. Each of the blades pivots between an expanded position and a closed position.

A wind turbine includes twin cross-flow turbines connected to a generator. The generator includes a shaft configured to be rotated when the turbines rotate. The wind turbine includes a first turbine rotatably movable around a first axis of rotation and including several blades distributed around the first axis of rotation. A second turbine is rotatably movable around a second axis of rotation and includes several blades distributed around the second axis of rotation. The first axis of rotation and the second axis of rotation are symmetrical to each other relative to a vertical axis. The first axis of rotation and the second axis of rotation are inclined relative to the vertical axis at an angle of inclination of between 25? and 50?.

A method of damping oscillations in a multi-rotor wind turbine and a wind turbine are provided. The wind turbine comprises a wind turbine support structure and at least a first nacelle with a first rotor and a second nacelle with a second rotor, at least one of the nacelles being located at a position away from a central longitudinal axis of the wind turbine support structure. The method comprises the steps of receiving and processing motion data, selecting a damping algorithm and generating a pitch control signal. The processing comprises determining at least one prominent oscillation mode of the wind turbine support structure and selecting a corresponding damping algorithm.

Disclosed in the present invention is a dual-rotor microfluidic energy capturing and power generating device based on a piezoelectric effect. An inner ring of blades and an outer ring of blades are coaxially and movably sleeved, and rotate relatively. Sheet-like magnetic piezoelectric components and steel magnets are provided in an annular gap between the inner ring of blades and the outer ring of blades. Magnetic piezoelectric components are connected to an inner peripheral surface of the outer ring of blades, the magnetic piezoelectric components are magnetically repulsive to the steel magnets, and the outer sides of the magnetic piezoelectric components are axially arranged. The inner ring of blades and the outer ring of blades rotate relatively to drive the magnetic piezoelectric components and the steel magnets to rotate relatively, and further drive the magnetic piezoelectric components to oscillate to generate mechanical energy which is then converted into electric energy.

The present technology is directed to the design and relative placement of a plurality of rotor vanes against which a directional fluid flows thereby exerting a force against the vanes and rotating the vanes in a desired direction. The plurality of vanes is disposed about a central axis such that when the fluid exerts its force against the vanes the vanes rotate continuously about the central axis.

A wind turbine includes twin cross-flow turbines connected to a generator. The generator includes a shaft configured to be rotated when the turbines rotate. The wind turbine includes a first turbine rotatably movable around a first axis of rotation and including several blades distributed around the first axis of rotation. A second turbine is rotatably movable around a second axis of rotation and includes several blades distributed around the second axis of rotation. The first axis of rotation and the second axis of rotation are symmetrical to each other relative to a vertical axis. The first axis of rotation and the second axis of rotation are inclined relative to the vertical axis at an angle of inclination of between 25? and 50?.

A system with a first turbine rotating in a first direction and a second turbine rotating in a second direction, wherein there is negative clearance associated with blades of the first turbine and the blades of the second turbine.