Multi-stable mechanism of an oscillating-body wave energy converter

Li, Liang and Zhang, Xiantao and Yuan, Zhiming and Gao, Yan (2019) Multi-stable mechanism of an oscillating-body wave energy converter. IEEE Transactions on Sustainable Energy. ISSN 1949-3029

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    Abstract

    The present research aims to utilize the multi-stable mechanism to increase the energy conversion of the oscillating-body wave energy converter (WEC). Considering that a majority of WEC concepts are linear and single-stable, a nonlinear spring-damper model is proposed to achieve the multi-stable mechanism. The system is either monostable or bistable depending on the initial condition of the springs. The energy conversion of a heaving point-absorber with the nonlinear spring-damper model is investigated in the present research. Firstly, a state-space dynamic model of the heaving point-absorber is developed. Then the energy conversion at both the monostable mode and the bistable mode is simulated. The present research also illustrates the response feature at the two stable modes. It is found the nonlinear point-absorber behaves like a linear system in the monostable mode. The energy conversion is just increased slightly. Nevertheless, the energy absorption is increased substantially in the bistable mode. It is found that the velocity phase is adjusted in the bistable mode, leading to the enhancement of the energy conversion.