Platform for generating electricity from flowing fluid using generally prolate turbine

Abstract

A platform-like device for generating electricity from moving fluids has two has at least two fluid turbines coupled to one another through a frame. The fluid turbines are adapted to rotate in opposite directions. The fluid turbines also provide buoyancy for the platform so that the platform is self supporting in the water. The fluid turbines preferably have helicoid flights (screw-like threads) mounted to generally prolate casings. The fluid turbines preferably connect to electric generators through belt, chain-drive, or other transmission systems. The platform may additional support a wind turbine.

What is claimed is: 
     
         1 . An electricity-generating platform having a buoyancy, comprising:
 (A) a frame;   (B) at least two fluid turbines, each fluid turbine coupled to the frame and adapted to rotate about an axis when placed in a stream of flowing water, said fluid turbines collectively providing a substantial majority of the buoyancy for the platform, wherein
 (i) a first of the at least two fluid turbines is adapted to rotate in a first direction around its axis of rotation, and 
 (ii) a second of the at least two fluid turbines is adapted to rotate in a second direction around its axis of rotation, said second direction being opposite the first direction; and 
   (C) at least one electric generator coupled to at least one of the at least two fluid turbines and adapted to generate electricity in response to rotation of the at least one of the at least two fluid turbines.   
     
     
         2 . A platform as in  claim 1  wherein the fluid turbines collectively provide substantially all of the buoyancy for the platform. 
     
     
         3 . A platform as in  claim 1  wherein the platform buoyancy is configured to bias the frame to a position where the at least one generator is above the water line. 
     
     
         4 . A platform as in  claim 1  wherein said at least one electric generator comprises at least one generator for each of the at least two fluid turbines. 
     
     
         5 . A platform as in  claim 1  wherein said at least one electric generator comprises at least two generators for each fluid turbine. 
     
     
         6 . A platform as in  claim 1  wherein said at least one electric generator comprises two turbines and two generators for each fluid turbine. 
     
     
         7 . A platform as in  claim 1  wherein a fluid turbine couples to a generator through a chain drive. 
     
     
         8 . A platform as in  claim 1  wherein a fluid turbine couples to a generator through a belt drive. 
     
     
         9 . A platform as in  claim 1  wherein a fluid turbine comprises:
 (A) a generally prolate casing, and 
 (B) at least one helicoid working member fixedly attached to the casing. 
 
     
     
         10 . A platform as in  claim 1  further including a slack mooring coupled to the frame. 
     
     
         11 . A platform as in  claim 1  further comprising a housing coupled to the frame, and the platform buoyancy is configured to bias the frame to a position where a housing is above the water line. 
     
     
         12 . A platform as in  claim 11  further includes electric power distribution circuitry electrically coupled to the at least one generator, comprising:
 (A) a first rectifier converting AC electricity from a first generator into DC electricity; 
 (B) a second rectifier converting AC electricity from a second generator into DC electricity; and 
 (C) an inverter converting combined DC electricity from the first and second rectifiers into AC electricity. 
 
     
     
         13 . A platform as in  claim 12  wherein the electric power distribution circuitry further includes an electricity storage element. 
     
     
         14 . A platform as in  claim 1  further comprising an electricity generating wind turbine coupled to the frame. 
     
     
         15 . A platform as in  claim 14  further comprising electric power distribution circuitry configured to receive electricity generated by a fluid turbine and electricity generated by the wind turbine. 
     
     
         16 . A platform as in  claim 15  wherein the electric power distribution circuitry includes:
 (A) a rectifier circuit converting AC electricity generated by at least one fluid turbine into DC electricity; 
 (B) a rectifier circuit converting AC electricity generated by the wind turbine into DC electricity; and 
 (C) an inverter converting combined DC electricity from the fluid turbine and the wind turbine into AC electricity. 
 
     
     
         17 . A platform as in  claim 16  wherein the electric power distribution circuitry includes an electricity storage element. 
     
     
         18 . A platform as in  claim 17  wherein the electricity storage element includes a battery.