US 2011/0031756 A1 · SELF-STARTING DARRIEUS WIND TURBINE

Abstract

A Darrieus rotor supported by a bearing system to rotate about a vertical axis for capturing wind energy has an alternator that is directly-driven by the rotor and converts rotational power from the rotor into electrical power. An electronic controller controls the electrical load applied to the alternator and the power output from the alternator to an output. The alternator is constructed having a substantially constant reluctance torque for all angular positions of rotation of the rotor. The bearing system includes upper and lower rolling element mechanical bearings that provide radial support of the rotor against wind load and axial support of the rotor, and a magnetic bearing that provides axial lift that reduces the axial load on the mechanical bearings and reduces the starting torque for rotating the rotor. The electronic controller applies minimal electrical load to the alternator until the rotor is at a rotational speed greater than a deadband for the rotor in the instantaneous wind speed, whereby the electronic controller, the alternator and the bearing system together avoid retarding forces that would otherwise prevent passive self-starting.

Claims20

Dependent claims

A Darrieus wind turbine that is capable of passively self-starting by aerodynamic forces comprising:

a Darrieus rotor that is supported by a bearing system to rotate about a vertical axis for capturing wind energy;
an alternator that is directly-driven by said Darrieus rotor and converts rotational power from said Darrieus rotor into electrical power;
an electronic controller for controlling the electrical load applied to said alternator the power output from said alternator to an output;
said electronic controller, said alternator, and said a bearing system cooperate to facilitate said passive self-starting;
said alternator is constructed of a permanent magnet rotor and an aircore armature, wherein magnets on said permanent magnet rotor drive magnetic flux across an armature airgap, and said aircore armature is constructed of windings in a substantially non-ferromagnetic structure where located inside said armature airgap;
said bearing system comprises upper and lower rolling element mechanical bearings and a magnetic bearing;
said mechanical bearings provide radial support of said Darrieus rotor against wind load and axial support of said rotor;
said magnetic bearing provides axial lift that reduces the axial load on said mechanical bearings and reduces the starting torque for rotating said Darrieus rotor;
said electronic controller applies substantially no electrical load to said alternator until said Darrieus rotor is at a rotational speed greater than a deadband for said Darrieus rotor in the instantaneous wind speed.

6 more elements

A Darrieus wind turbine that is capable of passively self-starting by aerodynamic forces comprising:

a Darrieus rotor, and an alternator, electronic controller and a bearing system that cooperate to facilitate said passive self-starting;
said Darrieus rotor is supported by said bearing system to rotate about a vertical axis for capturing wind energy;
said alternator is coupled to said Darrieus rotor and converts rotational power from said Darrieus rotor into electrical power, and said electronic controller controls the electrical load that is applied to said alternator and the power that is delivered to an output;
said alternator is constructed having a substantially constant reluctance torque for all angular positions of rotation of said rotor;
said bearing system comprises upper and lower rolling element mechanical bearings and a magnetic bearing;
said mechanical bearings provide radial support of said Darrieus rotor against wind load and axial support of said rotor;
said magnetic bearing provides axial lift that reduces the axial load on said mechanical bearings and reduces the starting torque for rotating said Darrieus rotor;
said electronic controller applies minimal electrical load to said alternator until said Darrieus rotor is at a rotational speed greater than a deadband for said Darrieus rotor in the instantaneous wind speed, whereby said electronic controller and alternator together avoid applying retarding forces that would otherwise prevent passive self-starting.

5 more elements

Dependencies are inferred from the claim text.

Self-starting darrieus wind turbine

Life of this patent

Self-starting darrieus wind turbine

Life of this patent

Abstract

Claims20