Optimal specification of the rotor voltage of a DFIG to maximize energy production with reactive power constraint
Wind power; Wind turbines; DFIG; Optimization.
Since the discovery of electricity, there has always been a search for the development of new means of power generation or ways to improve existing generation processes. Among the renewable energy sources, wind energy stands out in the world scenario regarding the growth potential of generation. In Brazil, this highlight is justified by data released by the Global Wind Energy Council (GWEC), which places Brazil as the ninth in the world list of countries with higher installed capacity for wind power generation. Within this general panorama it is important to mention that there are different wind turbine technologies. Many wind farms installed in Brazil and worldwide use the Doubly-Fed Induction Generator (DFIG), due to the evolution of the power electronic devices, vector control techniques of the machine and pitch control, which allow DFIG generators generate power at a wide wind speed range. This wind generator technology uses the asynchronous winding rotor machine, whose stator is connected to the grid and the rotor is powered from two bidirectional AC-DC converters in back-to-back connection, one of them being connected to the rotor and the another connected to the same stator bus. This type of asynchronous generator power supply coupled with the vector control techniques allows the control of the active and reactive energy production, as well as the control of losses in the generator, from the variation of the modulus and phase parameters of the rotor voltage. These controls are possible even with the machine operating at speeds below the synchronous speed, a characteristic that justifies its use in the most diversified wind power generation environments. This work seeks to study the different types of control applied to the aerogenerator of the DFIG type, and using optimization techniques to reach optimum values of modulus and phase of the rotor feed voltage for the various operating conditions of the aerogenerator considering the limitations imposed by the environment or by the asynchronous generator used.