Determination of the Power Resonant Frequency of an OWC Converter Based on the RLC Circuit Analytical Approach

The oscillating water column is one of the most applicable and commercialized wave energy converters. There are some analytical-based simplified approaches like the rigid piston model for analyzing such converters in which the dynamic motion's damping, inertia, and stiffness are respectively modeled with a resistor, inductor, and capacitor (an RLC circuit). The power resonant frequency of wave energy converters is computed by solving the motion equation via its equivalent RLC circuit model. The free decay test is the other simple method for determining the resonant frequency and has been investigated experimentally. However, a comprehensive study is required. In this investigation, first, the effect of parameters like pressure, flow rate, and their phase difference on power resonant frequency, capture factor, etc., are conceptually investigated. Then, the relation between resonant frequency and free decay test frequency is studied for different chamber sizes. The results indicate that the free decay test frequency is generally close to the power resonant frequency.