On the Modeling of an OWC Wave Power System

Abstract

Considering the nonlinear characteristics of the Wells turbine and random and irregular characteristics of ocean waves, a mathematical model of OWC wave power system in time domain is more useful. The model currently used in time domain is written in the form of a differential-integral equation by using impulse response function, which is not convenient for the research of control problem especially when modern control methods are applied in the research. So, a state space model is useful for the study of OWC wave power system. In this paper, system realization techniques are applied to establish a state space model for OWC wave power system from the impulse response function. The integral term of the differential-integral equation is replaced by a linear part system whose output is equal to the integral term and the motion velocity of OWC is looked as the input of the system. System parameters of the part system are optimally determined by using Gauss-Newton least square method. Two fixed terminator type OWC wave power devices are considered as calculation examples. Simulating results show that the state space model is in good agreement with the impulse response function model. Besides OWC wave power system, the modeling techniques proposed in the paper can also be used in the modeling of other ocean dynamic systems.