Novel electrical generators for use in unmoored buoys and the like platforms with low-frequency and time-varying oscillatory motions

Abstract

A buoy for generating electrical energy from an roll/pitch motion resulting from a passing wave. The buoy including: a body; a pendulum member rotatably disposed on the body at a first end of the pendulum member; a pendulum mass disposed at a second end of the pendulum member; an exciter mass positioned on the pendulum member between the first and second ends; and one or more generators for generating electrical energy, the one or more generators being positioned in the body such that swinging of the pendulum member due to the roll/pitch motion causes a portion of the exciter mass to engage the one or more generators to generate the electrical energy.

1 . A buoy for generating electrical energy from an roll/pitch motion resulting from a passing wave, the buoy comprising:
 a body;   a pendulum member rotatably disposed on the body at a first end of the pendulum member;   a pendulum mass disposed at a second end of the pendulum member;   an exciter mass positioned on the pendulum member between the first and second ends; and   one or more generators for generating electrical energy, the one or more generators being positioned in the body such that swinging of the pendulum member due to the roll/pitch motion causes a portion of the exciter mass to engage the one or more generators to generate the electrical energy.   
     
     
         2 . The buoy of  claim 1 , wherein the exciter mass has tips for engaging the one or more generators when the pendulum member swings in first and second directions. 
     
     
         3 . The buoy of  claim 1 , wherein the pendulum mass is releasably retained against a surface of the body and released by the roll/pitch motion. 
     
     
         4 . The buoy of  claim 1 , wherein the exciter mass is separate from the pendulum mass. 
     
     
         5 . The buoy of  claim 1 , wherein the one or more generators are piezoelectric generators. 
     
     
         6 . The buoy of  claim 1 , wherein the body has a cross-section such that it is stabile in a rotation direction. 
     
     
         7 . The buoy of  claim 1 , wherein the body has one or more fins so as to be stabile in a rotation direction. 
     
     
         8 . A method for generating electrical energy from an roll/pitch motion resulting from a passing wave, the method comprising:
 rotatably disposing a pendulum member on a body of a buoy at a first end of the pendulum member;   disposing a pendulum mass at a second end of the pendulum member;   positioning an exciter mass on the pendulum member between the first and second ends; and   generating electrical energy resulting from a swinging of the pendulum member due to the roll/pitch motion by causing a portion of the exciter mass to engage at least one generator to generate the electrical energy.   
     
     
         9 . The method of  claim 8 , further comprising offsetting the pendulum mass such that the body of the buoy is heeled to one side when floating in water. 
     
     
         10 . The method of  claim 9 , wherein the wherein the offsetting comprises releasably retaining the pendulum mass against a surface of the body. 
     
     
         11 . The method of  claim 10 , wherein the pendulum mass is released from the surface of the body by the roll/pitch motion to cause the exciter mass to engage the at least one generator to generate the electrical energy. 
     
     
         12 . The method of  claim 11 , wherein, after the release of the pendulum mass from the surface, the pendulum mass is releasably retained on another surface of the body. 
     
     
         13 . The method of  claim 12 , wherein the pendulum mass is released from the another surface of the body by the roll/pitch motion to cause the exciter mass to again engage the at least one generator to generate the electrical energy. 
     
     
         14 . A buoy for generating electrical energy from an roll/pitch motion resulting from a passing wave, the buoy comprising:
 a body;   an eccentric mass rotatably disposed on the body; and   at least one generator disposed around an engagement portion of the eccentric mass for generating electrical energy, the at least one generator being positioned in the body such that rotation of the eccentric mass due to the roll/pitch motion causes a portion of the exciter mass to engage the at least one generator to generate the electrical energy.   
     
     
         15 . The buoy of  claim 14 , wherein the portion comprises tips for engaging the at least one generator when the eccentric mass rotates. 
     
     
         16 . The buoy of  claim 14 , wherein the eccentric mass is releasably retained against a surface of the body and released by the roll/pitch motion. 
     
     
         17 . The buoy of  claim 14 , wherein the one or more generators are piezoelectric generators.