Output power control of a wind energy conversion system based on a doubly fed induction generator

In this paper, a control of a variable wind energy conversion system (WECS), based on a doubly fed induction generator (DFIG) is proposed. The wind turbine and the machine model are both presented. The DFIG control structure contains rotor currents and stator powers loops where PI controllers are used. This control could be obtained by applying a DFIG active and reactive power decoupling strategy based on stator flux orientation method. For the wind turbine, a nonlinear controller based on a sliding mode theory is adopted to maximize the extracted power. This controller works in the partial load region. Another control algorithm has been used to work in full load region. It controls the generator output power via the pitch angle so as not to exceed the rated power of the system. Proposed MPPT and pitch control algorithms provide good static and dynamic performances. Validity of proposed strategies is analyzed throw simulation.