Airborne wind energy system with enhanced power transfer

Abstract

An improved wind power device for wind energy conversion or vehicle propulsion. Among many possibilities contemplated, the device may have a moving sail with tethered wings ( 101 ), moving in elliptical trajectory, utilize separate sheave ( 503 ) and cable drum ( 505 ), use a block and tackle ( 411 ), attached to the tether and utilize a cable having a flexible jacket with aerodynamically streamlined cross section ( 603 ).

What is claimed is: 
     
         1 . A device for conversion of wind energy into electric energy, comprising:
 an airborne wing, adapted to move in the air under power of wind;   a round or aerodynamically streamlined cable, coupled to the airborne wing by one of the cable's ends;   a perforated belt, attached to another end of the cable;   a ground level platform;   an electrical generator, installed on the platform;   a sprocket, rotationally coupled to a rotor of the electrical generator, the sprocket adapted to be engaged by the perforated belt.   
     
     
         2 . The device of  claim 1 , further comprising a drum for the perforated belt. 
     
     
         3 . The device of  claim 2 , wherein the sprocket has smaller diameter than the belt drum, thereby achieving higher angular speed of the sprocket. 
     
     
         4 . The device of  claim 1 , further comprising an electronic control system, including a first control element installed on the platform, a second control element, installed on the wing, and a network link between them. 
     
     
         5 . A method of converting wind power into electric power, comprising:
 providing an electrical generator on the ground;   harvesting wind power using an airborne wing with an attached cable, the cable having a streamlined or round section, the airborne wing pulling the attached cable while flying mostly cross wind;   converting the pull of the cable into a linear motion of a perforated belt by connecting a free end of the belt to the cable;   converting the linear motion of the perforated belt into rotational motion of a sprocket by engaging the sprocket by the perforated belt;   converting the power of the rotational motion of the sprocket into electrical power using the electrical generator through rotational coupling between the sprocket and a rotor of the electrical generator.   
     
     
         6 . The method of  claim 5 , further comprising a step of providing a drum for the perforated belt and further comprising two alternating operational phases:
 the first phase comprising the airborne wing moving away from the sprocket, the perforated belt reeling off the drum and electrical power being generated by the electrical generator;   the second phase comprising the airborne wing moving toward the sprocket, the perforated belt reeling on the drum and electrical power being consumed;   wherein significantly more electrical energy is generated in the first phase than consumed in the second phase.   
     
     
         7 . The method of  claim 5 , further comprising the step of utilizing an electronic control system to control the electrical generator, the drum, the motion of the airborne wing and to synchronize reel on/reel off of the belt with the motion of the airborne wing.