In this study, an in-house code to perform aerodynamic design and performance prediction of a small-capacity wind turbine rotor including furling system has been developed. The code was made to have GUI environment with Matlab. The aerodynamic design of a blade in the code is performed based on the blade element momentum theory, and Xfoil is used to obtain aerodynamic data for sections(airfoils) of the blade based on the panel method. The code was made to predict the rotor performance including a side-furling system which is commonly used as overspeed protection mechanism for small-capacity lift-type wind turbines. Also the code has a functionality to find out optimal torque schedule for power maximization and power regulation for below and above rated wind speed regions, respectively.
To validate the code without the furling system, a commercial wind turbine named SERI-8 was modeled and simulated using the program. The simulation results were compared with the simulation results available in the literature. The validation of the code with the furling system was also performed with a commercial wind turbine named Excel 10 with a side-furling system. The simulation results with the proposed code compared with the results obtained with the aero-elastic simulation tool, FAST developed by NREL, with the same (Excel 10) geometry and the wind turbine torque control method. For both simulations with two different wind turbines, the results from the proposed code were found to be close to the results in the literature or by FAST.
Finally, using the proposed code, the torque schedule of the Excel 10 wind turbine was optimized to maximize the power coefficient below the rated wind speed, and to regulate the power output not to exceed the rated power. The optimized torque schedule was found to increase the power production of Excel 10 substantially and to regulate the power better not to exceed the rated power compared with the performance of the same wind turbine available in the literature.