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Wave energy converters incorporating the components of an induction generator that are integrated with the components of a pneumatic spring are provided. The wave energy converters have a buoy having an interior guide, motion of the buoy representing a first degree of freedom and a spar mounted with

Wave energy converters incorporating the components of an induction generator that are integrated with the components of a pneumatic spring are provided. The wave energy converters have a buoy having an interior guide, motion of the buoy representing a first degree of freedom and a spar mounted within the interior guide so as to be movable therein, motion of the spar representing a second degree of freedom. There is a pneumatic spring between the spar and the buoy to provide restoring forces when the spar departs from a quiescent position relative to the buoy. There is damping element in the form of an induction generator having an armature and a stator, with one of the stator and armature fixed to the spar and the other of the stator and armature fixed to the buoy to generate power when the spar moves relative to the buoy in the presence of excitation by ocean gravity waves. The mass of the wave energy converter and dimensions of the buoy are such that in use, the buoy floats in a partially submerged position.

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1. A wave energy converter with two degrees of freedom comprising: a buoy having an interior guide, motion of the buoy representing a first degree of freedom;a spar mounted within the interior guide so as to be movable therein, motion of the spar representing a second degree of freedom;a pneumatic s

1. A wave energy converter with two degrees of freedom comprising: a buoy having an interior guide, motion of the buoy representing a first degree of freedom;a spar mounted within the interior guide so as to be movable therein, motion of the spar representing a second degree of freedom;a pneumatic spring between the spar and the buoy to provide restoring forces when the spar departs from a quiescent position relative to the buoy; anda damping element in the form of an induction generator having an armature and a stator, with one of the stator and armature fixed to the spar and the other of the stator and armature fixed to the buoy to generate power when the spar moves relative to the buoy in the presence of excitation by ocean gravity waves;wherein the mass of the wave energy converter and dimensions of the buoy are such that in use, the buoy floats in a partially submerged position. 2. The wave energy converter of claim 1, wherein the pneumatic spring is an asymmetric pneumatic spring having a hard spring characteristic in one direction and a soft spring characteristic in the other direction. 3. The wave energy converter of claim 2, wherein: the spar provides a secondary mass and also functions as a piston of the pneumatic spring;the induction generator comprises: the stator mounted to the top of the spar;the interior guide of the buoy functioning as the armature. 4. The wave energy converter of claim 1, further comprising at least one valve for adjusting a pressure within the pneumatic spring. 5. The wave energy converter of claim 1, wherein the interior guide of the buoy comprises the armature, the armature comprising a cylinder of aluminum mounted within a cylinder of steel. 6. The wave energy converter of claim 1, further comprising: bearing assemblies to maintain a specified separation between the stator and the armature in the presence of a magnetic attraction force between the armature and the stator. 7. The wave energy converter of claim 2, wherein: the spar provides a secondary mass and also functions as the armature;the induction generator further comprises the stator mounted at a bottom of the buoy. 8. The wave energy converter of claim 1, wherein the spar has a streamlined projected area. 9. The wave energy converter of claim 8, wherein the streamlined projected area has a hemispherical or prolate spheroid shape. 10. The wave energy converter of claim 1, wherein the spar has a diameter that is small at the water line and is made larger at depth by incorporating a streamlined change in the spar diameter. 11. The wave energy converter of claim 1, wherein the pneumatic spring is a symmetric pneumatic spring. 12. The wave energy converter of claim 11, wherein the pneumatic spring comprises a pneumatic cylinder above the interior guide of the buoy, the pneumatic cylinder functioning as the distributed armature of the induction generator; the wave energy converter further comprising a piston within the pneumatic cylinder connected to the spar with at least one connecting rod;the stator is integrated into the piston assembly;wherein a first chamber of the symmetric pneumatic spring is defined between a bottom of the piston and a bottom of the pneumatic cylinder, and a second chamber of the symmetric pneumatic spring is defined between a top of the piston and a top of the pneumatic cylinder. 13. The wave energy converter of claim 12, further comprising at least one valve for adjusting a pressure within the first chamber, and at least one valve for adjusting a pressure within the second chamber. 14. The wave energy converter of claim 12, further comprising: bearing assemblies that support the spar within the interior guide. 15. The wave energy converter of claim 12, wherein the at least one connecting rod comprises an elliptical connecting rod. 16. The wave energy converter of claim 1, wherein the induction generator comprises a two-sided stator. 17. The wave energy converter of claim 16, wherein: the pneumatic spring comprises a pneumatic cylinder above the interior guide for the spar, the pneumatic cylinder functioning as the armature of the induction generator;the wave energy converter further comprising a piston within the pneumatic cylinder connected to the spar with at least one connecting rod;the induction generator comprises a first stator inside the pneumatic cylinder supported by the piston, and a second stator outside the pneumatic cylinder that is connected to the spar with at least three equispaced connecting rods;wherein a first chamber of the pneumatic spring is defined between a bottom of the piston and a bottom of the pneumatic cylinder, and a second chamber of the pneumatic spring is defined between a top of the piston and a top of the pneumatic cylinder. 18. The wave energy converter of claim 17, further comprising guides for the connecting rods in a top plate of the interior guide so as to constrain the relative rotational motion between the spar and the buoy. 19. The wave energy converter of claim 1, wherein the armature comprises a ladder arrangement having alternate placement of aluminum and steel rings inside or outside a steel component. 20. The wave energy converter of claim 1, wherein the induction generator is tubular. 21. The wave energy converter of claim 1, further comprising: a vector controller that controls force and flux density independently. 22. The wave energy converter of claim 1, wherein the armature is a distributed armature. 23. The wave energy converter of claim 1, wherein the armature has a ladder construction. 24. The wave energy converter of claim 1, wherein the wave energy converter is configured to provide a bandwidth that matches or is included in a bandwidth of an average wave height spectrum for a site of interest.