Introduction of Automatic Braking System and auxiliary starting mechanism using wave force for Small Vertical Axis Wind Turbine

Abstract

Recently, wind power has become an energy source that is expected to increase installation in Japan as wind power prices decrease internationally. However, wind power generation in Japan is still low compared to international standards, and the cost of power generation is high. Therefore, we have been working on small-scale power generation, especially small vertical-axis wind turbines, to adapt the wind turbines to the wind conditions in Japan.
In this study, (1) an auxiliary starting mechanism using wave force was installed in the device, (2) designed and fabricated to compare with drag and lift types, and (3) a rotational speed detection mechanism to introduce a braking system into the system. The drag-type wind turbine was tested in a simple wind tunnel. As a starting aid mechanism, a float attached to the bottom of the float support is floated on the surface of the water, and its vertical movement is converted into horizontal rotation by a combination of gears to turn the wind turbine shaft. The size of the wind turbine is 0.58 [m] in diameter, 0.73 × 0.23 [m] in blades, and 6.70 [kg] in total weight. As a result of the characteristic test of the drag-type wind turbine, it was confirmed that the cut-in wind speed was 3.7 [m/s], the sustained wind speed was 3.3 [m/s], and the maximum power was 0.50 [W] at a load resistance value of 150 [Ω]. For the brake system, a torque of approximately 0.06 to 0.12 [N-m] was obtained to determine the braking strength.