The double-fed electric machines are electric motors or electric generators where both the field magnet windings and the armature windings are connected separately to equipment outside the machine. By feeding frequency adjustable AC power to the field windings, the magnetic field can be rotated, allowing variation in motor or generator speed. This is useful, for example, for generators used in wind turbines.
For a long time, electromechanical systems used squirrel cage induction motors, as main actuators; however, dual-feed induction motors, present with estimable advantages in variable speed drive. From this, the performance of the conventional speed controllers are sensitive to variations of motor parameters. Thus, in this work, the analysis of fuzzy speed controller performance is presented. The results of the simulation showed that the fuzzy logic controller ensures the best dynamic performance in rotor resistance and load variations.
The double feed induction machine using an AC-AC converter in the rotor circuit (Scherbius drive) has long been a standard drive option for high power applications involving a limited speed range. The power converter should only be rated to handle the rotor power. Vector control techniques for independent control of torque and rotor excitation current are well known, whereas Jones and Jones, for example, have demonstrated that a vector control strategy for the uncoupled power control Active and reactive extraction from the supply. Wind power generation is considered as a natural application for the Scherbius DFIG system, since the speed range (from shear to nominal wind speed) can be considered restricted.
Double-fed electric machines are electric generators that have windings on stationary and rotating parts, where both windings transmit significant power between the shaft and the electrical system. Rohini G writes about the technical knowledge of the advance mechanism used in wind power generation.
With industrial and demographic growth, energy consumption has increased significantly over the past three decades. The serious problem of the depletion of resources such as coal, gas and oil at a very rapid pace has motivated countries around the world to think of alternative natural resources that are inexhaustible, sustainable and environmentally friendly. Among non-conventional resources for electricity, wind energy has attracted great interest in recent decades and has undoubtedly been the fastest growing renewable energy source. Although the wind industry is young from the point of view of the power generation system, it has benefited significantly from the continuous technological advances made in the components related to the integration of the grid, the electric machine, the power converters and the Ability to control. The days of the simple squirrel cage induction machine have long since disappeared. Now we can control the actual and reactive power of the machine, limit the power output and control the voltage and speed.
Meanwhile, doubly-powered electric machines have only recently come into common use with the advancement of wind power technologies for power generation. They are three-phase induction machines with variable speed coil rotor with advantages over other types of generators when used in wind turbines. Double-fed electric machines are electric generators that have windings in both stationary and rotating parts, where both windings transmit significant power between the shaft and the electrical system.