A wave energy converter includes a surface float including a non-axisymmetric profile, a reaction plate configured to be submerged below a water surface, and more than one flexible tether, each mechanically coupled to both the surface float and the reaction plate, the reaction plate having a moment of inertia in pitch and roll greater than a moment of inertia in pitch and roll of the surface float.

A power generation element and an actuator for vibration power generation is provided that can be mass-produced at low cost while achieving increase in electromotive force. A power generation element includes a main series magnetic circuit having a frame yoke made of magnetic material and provided with a fixed portion that is one end and a free portion that is the other end across a U-shaped bent portion, a main magnet that applies a magnetic bias to the frame yoke, and a first gap formed at a position in contact with the free portion; and an auxiliary series magnetic circuit having an auxiliary yoke made of magnetic material and attached to the frame yoke, an auxiliary magnet that gives a magnetic bias to the auxiliary yoke, a second gap formed at a position facing the first gap across the free portion, the frame yoke, the main magnet, and the first gap. The amount of change in a main magnetic flux passing in a coil wound around the frame yoke increases when the free portion vibrates due to application of an external force and a magnetic resistance of the first gap and a magnetic resistance of the second gap increase or decrease reciprocally.

The bluff body attaches to an elastic mount and is capable of generate vortex shedding when the elastic mount orients the bluff body in a flow-line traverse to a fluid flow and vibrates in response to the vortex shedding. A harvester is located within the bluff body and is capable of generating power above a specified threshold in response to the vibration.

The bluff body attaches to an elastic mount and is capable of generate vortex shedding when the elastic mount orients the bluff body in a flow-line traverse to a fluid flow and vibrates in response to the vortex shedding. A harvester is located within the bluff body and is capable of generating power above a specified threshold in response to the vibration.

The bluff body attaches to an elastic mount and is capable of generate vortex shedding when the elastic mount orients the bluff body in a flow-line traverse to a fluid flow and vibrates in response to the vortex shedding. A harvester is located within the bluff body and is capable of generating power above a specified threshold in response to the vibration.

The bluff body attaches to an elastic mount and is capable of generate vortex shedding when the elastic mount orients the bluff body in a flow-line traverse to a fluid flow and vibrates in response to the vortex shedding. A harvester is located within the bluff body and is capable of generating power above a specified threshold in response to the vibration.

A power generating apparatus includes a power generating element, a lever mechanism including a force point, a support point, and an action point, a first magnetic body disposed on the lever mechanism, and a second magnetic body having magnetic characteristics of being attracted to the first magnetic body. Upon the lever mechanism being pressed, the action point applies a load to the power generating portion and the first magnetic body approaches the second magnetic body while being attracted to the second magnetic body.

The bluff body attaches to an elastic mount and is capable of generate vortex shedding when the elastic mount orients the bluff body in a flow-line traverse to a fluid flow and vibrates in response to the vortex shedding. A harvester is located within the bluff body and is capable of generating power above a specified threshold in response to the vibration.

A power generation system includes a first power generation apparatus and a second power generation apparatus outputting alternating voltages by an input of vibrations; a first voltage-doubling rectifier circuit not only rectifying the alternating voltages output by the first power generation apparatus to store electricity, but also outputting enhanced voltages to the load instrument; a second rectifier circuit rectifying the alternating voltages output by the second power generation apparatus, and connected in series to the first voltage-doubling rectifier circuit, thereby outputting rectified voltages to the load instrument; a constant-current circuit connected in series to the load instrument, thereby limiting currents flowing to the load instrument to a predetermined current or less.

A sensor for sensing stress in a ferromagnetic material includes a non-magnetic substrate. The substrate has a first surface and a second surface opposite the first surface. A first coil is attached to or formed on the first surface of the substrate. The first coil is configured to induce a magnetic flux in the ferromagnetic material being driven by an alternating current (AC) signal. At least one second coil is attached to or formed on the first surface of the substrate. The at least one second coil is spaced from the first coil. In addition, the second coil is configured to detect changes in the magnetic flux induced in the ferromagnetic material.