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The major objective of the investigation reported in this article is to demonstrate the feasibility of controlling a Doubly Fed Induction Generator actuating directly on the rotor voltage produced by the Rotor Side Converter, as its reference value may be determined analytically, after definition of the control objective. Two usual objectives are here considered: maximum power extraction from wind (MPPT) and stator reactive power equal to zero. This last objective defines the reference slip to be considered in the formulation of developed power that, jointly with the reactive power equation, forms the system to calculate the rotor reference voltages. The process is completed by specifying the desired dynamical response. Thus, the angular velocity of the rotor should quickly reach its reference value, which requires maximal power acceleration at the beginning, but respects the restriction that no overshoot should be allowed. This is achieved by means of a constrained optimization process solved in real time. Following recent trends, only measurements obtained from stator (voltages and currents) sensors are used. This way, angular velocity and rotor currents are estimated in real time. An algorithm for inductance estimation is also included, which prevents deviations of nominal values that could lead to false reference voltages.

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This work presents a description of the development of a model for representation of simplified grid applied in hybrid load flow for calculation of the voltage variations in steady-state provoked by wind farm on power system with two different treatments for boundary buses. At the beginning of the analysis process on system, lead for the wind producer, it has as base given technician data supplied by the concessionaire. The main aim consists to propose models of simplified networks that allow to the necessity of the knowledge only of the data referring the internal network, that is, the parcel of the network of interest for analysis. This way, it is intended to supply forms for auxiliary in the systematization of the relations between the sector agents. The model of simplified network proposed identifies the internal network, external network and the boundary buses from a vulnerability study of the grid, testing to the boundary buses active and reactive powers floating model (slack buses) and determination of powers by optimization process using Particle Swarm Optimization. It was opted to apply the cited model in a hybrid load flow, composite by Gauss Seidel Zbus and Summation Power methods. Finally, presents the results obtained for a developed computational environment of FORTRAN, with their respective analysis and conclusion.