An approach for the transient behavior of horizontal axis wind turbines using the blade elementtheory

Abstract

In this work, an efficient mathematical model applied to transient behavior of Horizontal-Axis Wind Turbines (HAWT) was developed. The influence of the power drive on HAWT dynamic modelling was taken into account, in order to present an improved approach for the design of wind power systems. In all simulations, a rotor with 30 m diameter operating at 20 m/s wind velocity was used. The driveline comprises the mass-moment of inertia, electromagnetic torque, and the friction torque of whole system. To solve the nonlinear dynamic equation at each time step, 4th order Runge-Kutta numerical method was considered, while a Newton-Raphson scheme was applied to the steady-state regime. In addition, to calculate the aerodynamic torque, the Blade Element Theory (BET) was implemented, since such a parameter is usually obtained through approximated mathematical functions, mainly those applied to large wind turbines as described in several works available in the literature. BET is a well-known method applied to design and aerodynamic analysis of wind turbines, which presents good agreement with experimental data. To conclude, the results show the rotational speed, output power and torque dependents on time, and depict good behavior when compared with Bao and Ye (2001). An application using BET was also carried out, which yielded consistent results.