Session: 09-05-05 Wave Energy: Oscillating Water Columns

Submission Number: 181188

Towards Performance Optimization of an Oscillating Water Column Wave Energy Converter via Turbine Control and Impedance Matching 

This study investigates performance optimization strategies for an Oscillating Water Column (OWC) wave energy converter. The OWC is equipped with a full impulse turbine Power-Take-Off (PTO) system that is being dry tested in the laboratory using a piston to push air through the system, simulating the effect of regular waves at different wave periods. The device’s pneumatic power characteristics are understood based on previous wave-basin experiments with geometrically similar OWC configurations. The first objective for performance optimization is to maintain turbine operation at its optimal efficiency point through real-time closed-loop control. A PID controller regulates an electromagnetic control torque applied to the generator via a DC–DC converter, depending on the current rotational speed and airflow of the turbine. The second objective is to enhance the overall hydrodynamic power transfer by matching the impedances of the air chamber and the PTO. The idea here is to adjust the OWC's geometry accordingly to have impedance matching for a representative sea state. The system is currently being prepared for more dry testing to evaluate these control and impedance-matching strategies. Both approaches are first developed and validated in MATLAB/Simulink prior to experimental implementation. This paper presents the current progress, with emphasis on the coupled hydrodynamic and electrical models and their integration within the Simulink environment.

Presenting Author: Clara Vanessa Encke University of Hawaii

Presenting Author Biography: C. V. Encke is a PhD candidate at the Ocean and Resources
Engineering (ORE) Department at the University of Hawaii (UH) at
Manoa. Her research focuses on Wave Energy Converter Optimizations and Fluid-Structure Interactions.

Authors:

Clara Vanessa Encke University of Hawaii
Kyle Pappas University of Hawaii
Kumar Rajagopalan University of Hawaii
Ersegun Deniz Gedikli University of Hawaii
Terry Lettenmaier Williwaw Engineering
Troy Heitmann University of Hawaii
Patrick Cross University of Hawaii