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Ocean Systems Engineering Volume 3, Number 3, September 2013 , pages 203-217 DOI: https://doi.org/10.12989/ose.2013.3.3.203 |
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Enhancement of wave-energy-conversion efficiency of a single power buoy with inner dynamic system by intentional mismatching strategy |
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I.H. Cho and M.H. Kim
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| Abstract | ||
| A PTO (power-take-off) mechanism by using relative heave motions between a floating buoy and its inner mass (magnet or amateur) is suggested. The inner power take-off system is characterized by a mass with linear stiffness and damping. A vertical truncated cylinder is selected as a buoy and a special station-keeping system is proposed to minimize pitch motions while not affecting heave motions. By numerical examples, it is seen that the maximum power can actually be obtained at the optimal spring and damper condition, as predicted by the developed WEC(wave energy converter) theory. Then, based on the developed theory, several design strategies are proposed to further enhance the maximum PTO, which includes the intentional mismatching among heave natural frequency of the buoy, natural frequency of the inner dynamic system, and peak frequency of input wave spectrum. By using the intentional mismatching strategy, the generated power is actually increased and the required damping value is significantly reduced, which is a big advantage in designing the proposed WEC with practical inner LEG (linear electric generator) system. | ||
| Key Words | ||
| WEC(wave energy converter); relative heave motion; inner dynamic system; LEG(linear electric generator); double resonance; maximum PTO(power take off); intentional mismatching; high performance band-width | ||
| Address | ||
| I.H. Cho : 1Department of Ocean System Engineering, Jeju National University, Jeju 690-756, Korea M.H. Kim: Department of Civil Engineering, Texas A&M University, College Station, Texas, 77843, USA | ||
