A pitch system for rotating a blade of a wind turbine relative to a hub. The pitch system comprises a blade bearing including an inner bearing ring and an outer bearing ring, wherein the outer bearing ring is rotatable relative to the inner bearing ring, and an actuator system configured to control relative rotational movement between the inner bearing ring and outer bearing ring, comprising. The actuator system comprises a first load transfer beam arrangement spanning at least first and second fixing positions associated with the inner bearing ring, a second load transfer beam arrangement spanning at least first and second fixing positions associated with the outer bearing ring, and a first linear actuator coupled between the first load transfer beam arrangement and the second load transfer beam arrangement. A benefit of the pitch system of the invention is that it achieves a reduction in mass yet retains a stiff connection between the hub and an associated blade. Therefore, larger and heavier blades can be coupled to the pitch system whilst mitigating a proportional increase in mass of the pitch system.

A pitch system for rotating a blade of a wind turbine relative to a hub. The pitch system comprises a blade bearing including an inner bearing ring and an outer bearing ring, wherein the outer bearing ring is rotatable relative to the inner bearing ring, and an actuator system configured to control relative rotational movement between the inner bearing ring and outer bearing ring, comprising. The actuator system comprises a first load transfer beam arrangement spanning at least first and second fixing positions associated with the inner bearing ring, a second load transfer beam arrangement spanning at least first and second fixing positions associated with the outer bearing ring, and a first linear actuator coupled between the first load transfer beam arrangement and the second load transfer beam arrangement. A benefit of the pitch system of the invention is that it achieves a reduction in mass yet retains a stiff connection between the hub and an associated blade. Therefore, larger and heavier blades can be coupled to the pitch system whilst mitigating a proportional increase in mass of the pitch system.

A wind turbine including a lower mount; a nacelle; a hub rotatably coupled to the nacelle and configured to rotate about a longitudinal axis of the hub; a generator housed within the nacelle and configured to convert kinetic energy of the hub to electricity; a plurality of pivotable blades coupled to the generator and configured to rotate with the hub, each pivotable blade of the plurality of pivotable blades configured to pivot about a longitudinal axis of the pivotable blade; and an annular shroud fixed to the lower mount and located radially outward of the plurality of pivotable blades, the annular shroud coupled to the nacelle by at least one support member that is inclined so as to extend frontward and radially outward from the nacelle to the annular shroud; wherein the lower mount is configured to passively rotate about a mast.

A first aspect of the invention provides a pitch controlled wind turbine comprising a tower, a nacelle mounted on the tower, a hub mounted rotatably on the nacelle, and at least three wind turbine blades, wherein each wind turbine blade extends between a root end connected to the hub via a pitch mechanism, and a tip end, wherein each wind turbine blade comprises: a first blade portion having a shell that defines a suction side, a pressure side, a leading edge, a trailing edge, and a first spar cap portion, the first blade portion further including a first blade portion end surface at one end of the first blade portion; a second blade portion having a shell that defines a suction side, a pressure side, a leading edge, a trailing edge, and a second spar cap portion, the second blade portion further including a second blade portion end surface at one end of the second blade portion, wherein the first blade portion and the second blade portion are configured to be coupled together at the first and second blade portion end surfaces; and a connection joint for coupling the first and second blade portions together, wherein the connection joint includes a connector for connecting to the first blade portion end surface and to the second blade portion end surface, and wherein the pitch controlled wind turbine further comprises at least three blade connecting members, each wind turbine blade comprising a first connection point and a second connection point, wherein each blade connecting member extends between from a first connection point on one wind turbine blade and towards a second connection point on a neighbouring wind turbine blade, where each connection point on a given wind turbine blade is on the connector of the connection joint of that wind turbine blade.

The invention provides for controlling a wind turbine comprising pitch-adjustable rotor blades. The invention involves determining, based on detected wind conditions, wind turbine control parameters for controlling the wind turbine in accordance with a defined wind turbine control strategy, where the control parameters include a reference pitch angle for the rotor blades. The invention involves obtaining bearing control parameters each indicative of a parameter for controlling pitch bearings of the wind turbine that is for adjusting pitch of the rotor blades. The invention involves determining whether a defined set of operational parameters of the wind turbine, including the bearing control parameters, in combination correspond to a combination of operational parameters defined to be indicative of a level of wear above a threshold wear level. The pitch bearings are then controlled based on the reference pitch angle and on the threshold determination.