Electrical Generator Design for Darrieus-Type Wave Energy Converter

In this study, an electrical generator was designed for a wave energy converter in which the electricity is generated via horizontal axis-oriented Darrieus turbines installed in the naturally oscillating water near the breaking wave zone. The design goal is to achieve an average output power of >10 kW at 180 rpm, with safe underwater installation and waterproof construction. To verify the expected performance, a scaled-down generator was built with identical configurations, with the stack length reduced from 400 mm to 60 mm, and the expected output power reduced to >1 kW at 180 rpm under test conditions. The evaluation results showed that the desired characteristics were achieved with an output power of 1356 W at 180 rpm and an efficiency of 80.1%. Further, our height-adjustable platform ensures high efficiency at both low and high tide. The variable stack length in our WEC design allows the output power to be adapted to the specific location conditions. Once the experimental tests with the small-scale turbines are accomplished, we plan to conduct field tests with our full-scale wave energy converter.