Nonlinear variable speed control of wind turbines

While variable speed operation of wind turbines has several advantages, it poses difficult challenges in the design of control systems. The purpose of this work is to present a nonlinear variable speed control method for wind turbines. This method is based on the regulation of excitation winding voltage of the generator. Based on both mechanical and electrical dynamics, a nonlinear control algorithm is derived which is able to achieve smooth and asymptotic rotor speed tracking. The effectiveness of the method is verified via computer simulation with varying operating conditions.