The demand for electricity from renewable sources continues to rise, and with it, the need for more efficient wind energy conversion systems. Wind turbines equipped with a wound-rotor induction machine can be operated in a more efficient configuration than currently popular, with little to no change in system hardware. By coupling the machine to the grid inversely to the norm, losses in the sys...

This paper presents results of a study concerning the dynamic behaviour of a wind energy system powered by a doubly fed induction generator with the rotor connected to the electric network through an AC-AC converter. A tendency to put up more and more wind turbines can be observed all over the world. Also, there is awareness in taking into account the requirements of a clean environment, due to...

Wind energy is often installed in rural, remote areas characterized by weak, unbalanced power transmission grids. In induction wind generators, unbalanced three phase stator voltages cause a number of problems, including overheating and stress on the mechanical components from torque pulsations. Therefore, beyond a certain amount of unbalance (for example 6%), induction wind generators are swit...

This chapter introduces the operation and control of a Doubly-fed Induction Generator (DFIG) system. The DFIG is currently the system of choice for multi-MW wind turbines. The aerodynamic system must be capable of operating over a wide wind speed range in order to achieve optimum aerodynamic efficiency by tracking the optimum tip-speed ratio. Therefore, the generator’s rotor must be able to ope...

This paper describes the transient behaviour of a doubly-fed induction generator (DFIG) driven by wind turbine after its disconnection from the grid. The induction machine runs at a specific speed with the stator disconnected from the grid (Is=0), the rotor is suddenly excited with slip-frequency voltages derived from voltage regulators so as to produce commended open-circuit stator terminal vo...

In this paper we propose a new configuration of the wind farm connecting with an electrical grid. The proposed Wind Energy Conversion System (WECS) is based on a two stages six-leg matrix converter using to drive a two Doubly Fed Induction Machines operating at different wind speeds. Each Doubly Fed Induction Generator (DFIG) is controlled through the rotor currents using the Finite Set Model P...

In this paper steady state characteristic of a variable speed Doubly fed induction generator (DFIG) is investigated. Torque and speed is used as design parameters for DFIG. From mathematical model it is found that on increase of rotor injection voltage and resistance, the torque speed response is shifted from over synchronous to sub synchronous range. The stability of DFIG operation is entirely...

This paper presents fuzzy logic control of Doubly Fed Induction Generator (DFIG) wind turbine in a sample power system. DFIG consists of a common induction generator with slip ring and a partial scale power electronic converter. Fuzzy logic controller is applied to rotor side converter for active power control and voltage regulation of wind turbine. Wind turbine and its control unit are describ...

This chapter presents the theoretical basics of the electric power generation using doublyfed induction drives in wind turbines. This type of drive is the most utilized in wind power plants nowadays. This is mainly due to its fast dynamic response and reduced power electronics on the rotor side. This latter aspect is responsible for less harmonic pollution in the network and reduced acquisition...

The doubly fed induction generator (DFIG) is one of the most popular technologies used in wind power systems. With the growing use of DFIGs and increasing power system dependence on them in recent years, protecting of these generators against internal faults is more considered. Loss of excitation (LOE) event is among the most frequent failures in electric generators. However, LOE detection stud...