Online calculation of torque balance for power control of a DFIG connected to an electrical grid

A Newton-Raphson based algorithm is proposed for the solution of the transcendental equation that describes the torque balance between a Wind Energy Conversion System (WECS) and an Electrical grid. The WECS is considered operating in a different condition than the maximum power and with a passivity-based controller. The torque balance is calculated online to feed the control and regulate the active and reactive power dispatched to the grid for different wind speeds. The number of iterations is adjusted for a convergence criterion of 0.0001. The maximum time required by the proposed algorithm at each integration step on the passivity-based controller is 0.00366 s. The numerical results were obtained using commercial software on a 8 GB RAM computer with 1.8 GHz processor. The accuracy of the algorithm is verified with results reported in literature.