Downhole energy harvesting device

A method to operate a downhole energy harvesting device, the method comprising:

• receiving a fluid within a cavity of a stator having a longitudinal stator axis, the stator having a rotor disposed within the cavity, the rotor being adjacent to an armature having at least one winding and being operable to nutate along a longitudinal rotor axis, the longitudinal rotor axis being an offset of the longitudinal stator axis;
• nutating the rotor along the longitudinal rotor axis to generate an electrical current in the at least one winding;
• and
• transmitting the electrical current to an electrical component coupled to a downhole generator to power the electrical component;
• wherein the rotor is rotatably coupled to a magnetic gearing having a plurality of magnetic members, and wherein the magnetic gearing is rotatably mounted within a housing;
• and
• rotating the magnetic gearing along the longitudinal stator axis to generate the electrical current.

A downhole power generating system, the system comprising:

• at least one electrical component;
• and
• an energy harvesting device electrically coupled to the at least one electrical component, the energy harvesting device comprising:
• an outer stator having a first cavity formed therein;
• a rotor disposed within the first cavity, the rotor comprising a second cavity, at least one radial slot, and a helical slot extending from a first end of the rotor towards a second end of the rotor;
• an inner stator disposed within the second cavity;
• an armature adjacent to the rotor, the armature coupled to at least one winding coupled to the at least one electrical component to provide an electrical current to power the at least one electrical component;
• and
• a housing fixedly coupled to the outer stator;
• wherein the rotor is free to nutate between the inner stator and the outer stator;
• wherein the armature is stationary and is coupled to the housing;
• a magnetic gearing, wherein the magnetic gearing is coupled to the second end of the rotor and is rotatably mounted within the housing, and wherein the magnetic gearing is free to rotate within the housing;
• wherein the magnetic gearing comprises a plurality of magnetic members aligned around a surface of the magnetic gearing, and wherein the plurality of magnetic members is operable to generate the electrical current in the at least one winding;
• and
• wherein the armature is operable to generate the electrical current to power the at least one electrical component.