Page 38: of Marine Technology Magazine (April 2016)

Offshore: Wave Energy Prize

AquaHarmonics (Portland, Ore.)

AquaHarmonics’ Wave Energy Device is a point ab- sorber device consisting of a simple Power Take Off (PTO) system mounted in a cone/cylinder shaped hull with a single mooring line that has a power cable at its core. The PTO System consists of a sheave ? xed to a shaft mounted in bearings within a sealed com- partment and directly coupled to a pair of axial ? ux generators. The device only generates power on the rise of the wave, and during the fall of the wave the generators are operated as motors to reel in the moor- ing line for the next wave cycle.

During reel in, the control system of the device can provide additional energy input to achieve phase lock- ing with any wave frequency. This control method is known as “de-clutching,” which has been shown to ef- fectively increase the operational bandwidth of a wave energy device. The generated power is far greater than that consumed during the wave cycle with some en- ergy stored on board for periods of low wave activity.

The power is conditioned on board and sent to shore via a slipring on the shaft connected to the power cable located at the core of the mooring line.

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