The potential of wave energy source in the US is estimated to be 64% of the total electricity generated in 2010. Over 53% of the US population lives within 50 miles of the coasts, so ocean waves offer ready opportunity to provide electricity for the population without long-distance electricity transmission. The power takeoff - the machinery to convert the mechanical energy into electricity - is considered as the single most important element in wave energy technology, and underlies many of the failures of ocean wave energy systems to date. Revolutionary power takeoff is urgently needed in order to realize the high electricity potential from the untapped ocean waves. The objective of this Grant Opportunity for Academic Liaison with Industry (GOALI) project is to experimentally and theoretically investigate the design, modeling and control of an innovative ocean power takeoff mechanism to solve the most fundamental challenge in wave energy harvesting. The power takeoff offers much higher energy conversion efficiency, enhanced reliability, and unmatched compactness, and completely eliminates hydraulic components for potential environmental pollution. It can be integrated into the point absorbers, wave attenuators, wave terminators, or other type of wave energy converter whenever oscillatory wave motion is involved. Therefore, the success of this research will help establishing the leadership role of the US in the area of ocean wave energy. This project is expected to pave a sustainable energy pathway of harvesting vast but untapped ocean wave sources to meet the increasingly urgent national demand for energy and energy security.
Multidisciplinary research on energy manufacturing, marine hydrodynamics, mechatronics design, multi-physics modeling, control, and in-field study will be conduct in this project. The state-of-the-art ocean wave energy technology either uses direct-drive power takeoffs with linear electromagnetic generator or indirect-drive power takeoffs using intermediate fluid. The direct drives are simple and reliable but require heavy and bulk permanent magnets; the indirect drives are more compact but suffer from serious shortcomings on the complexity, reliability, and efficiency. The research team will create and investigate a "mechanical motion rectifier" based power takeoff to uniquely convert the irregular oscillatory wave motion into regular unidirectional rotation of the generator, having the advantages of direct and indirect drives. The research team will also systematically study the vibration energy harvesting synthesis from new perspective of modern electrical engineering including diodes and transistors. Multi-body dynamic motion magnification will also be investigated to significantly enhance the power extraction capacity.
