Browsing by Author "Eghbali Dogaheh, Seyed Hamed"

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    Offline Parameter Estimation of a 18.5 kW Doubly fed induction generator
    (Stellenbosch : Stellenbosch University, 2018-12) Eghbali Dogaheh, Seyed Hamed; Vermeulen, H. J.; Gule, Nkosinathi; Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering.
    ENGLISH ABSTRACT: In the past years, technology advancements have allowed the wind energy to become one of the most economical forms of power generation in the field of renewable energies. Nowadays, wind turbines that produce electricity make use of the advance and mature technologies and generate sustainable sources of energy. In the areas where the wind is plentiful, it is a major rival to the conventional sources of energy. Many countries worldwide have vast resources of it but still, haven’t used its capacity to the fullest. The upsides of wind energy are: . Omitting the emission of greenhouse gases. . The energy supplies can be increased and diversified using wind energy. . In comparison to the other power sources, a shorter time is required for planning, design, and construction.  The flexibility of such projects so that the current wind farms can host more turbines in case of higher demand for energy. . Finally, a significant saving in terms of materials, labor and investment. The extracted energy from the wind, is in the form of kinetic energy and is harnessed by the rotor blades and turned into mechanical energy. Then, this mechanical energy is transformed into the electrical energy by a wind turbine generator. The nominal power extracted from the wind varies based on the size of the rotor and the wind speed, regardless of the losses. The power ratings for wind generators varies from some hundred watts to multi-megawatt generators depending on the utilization and where they are stationed. Nowadays, a vast percentage of the larger scale wind generators employ the geared topologies, AC outputs connected to the power grid through power electronic converters, while it seems that the dynamic in the market is gradually changing towards employing the permanent magnet, gearless topologies by using the fully-rated power electronic converters. On the other hand, the small-scale turbines usually employ the direct drive generators with DC outputs and aeroelastic blades. However, the use of wind generators in a direct drive topology accompanied by the aeroelastic blades and DC outputs is rarely used and still under development. It is impossible to have the exact same power generation from the wind each year due to its variable nature. Furthermore, the wind generators can only be used in areas where a minimum speed of 4.5 m/s or higher is available. The suitable sites are chosen based on the measurements on the site and the data from a wind atlas. There are several methods for analyzing the dynamic behavior of the wind turbines. Employing the parameters of such systems is a suitable way to analysis the machine dynamic behavior and reduces complexities regarding the use of higher order models. The problem is that these parameters are subject to change in different operating conditions and need to be estimated accurately by some methods. This study concentrates on estimating the parameters of a doubly fed induction generator by employing the previously proposed Mathlab c-code and s-function codes and investigates the practical application of that method on a 18.5 kW doubly fed induction generator.