Tow tank testing and performance evaluation of a permanent magnet generator based small vertical axis hydrokinetic turbine

Vertical axis turbines using permanent magnet generators are being considered as options for use in hydrokinetic energy conversion. As a precursor to development of full-scale systems, scale-model turbines need to be tested in controlled environment. In this article, the results of tow tank testing of a small vertical axis turbine employing a permanent magnet generator are presented. Effects of rotor submersion, ripple propagation, and start-up behavior are presented along with relevant qualitative discussions. Results indicate an overall peak conversion efficiency of 22%. The critical limitations of these tests and general observations are also summarized at the end of this paper.