Enhancing Vertical Axis Wind Turbine Performance Investigation at Low Wind Speed Using Electrical Approach

This research provides an objective for a new approach to increase the hybrid Savonius-Darrieus Tip Speed Ratio range in a low-wind speed experiment (0–12 m/s) by considering the effect of power loss from the DC generator used. The models used are hybrid Savonius-Darrieus and single Darrieus with 4 blades. 2 stages of Savonius with 0.2 overlap and a 135° bucket angle are used as internal rotors, while the external rotor is a NREL S809 Darrieus airfoil with a cord length of 7 cm. A DC generator with a maximum voltage of 12 V is used. The friction, copper, and iron loss coefficients of the DC generator are 4.131, and 0.013, respectively. In the low wind speed experiment, the maximum Tip Speed Ratio that can be measured is around 1. Furthermore, by applying the improvement method in measurement, which involves applying constant current and variable voltage, the Tip Speed Ratio can reach 3.5-4. Thus, according to the findings, the hybrid Savonius-Darrieus and single Darrieus have maximum Power Coefficients of 0.30 at the Tip Speed Ratio of 1.5 and 0.33 at the Tip Speed Ratio of 3.3, respectively.