Simulador de Generador Eólico Doblemente Alimentado
[EN] This work begins in a laboratory of the Instituto de Ingeniería Energética (IIE) of the UPV to launch a wind simulator with a doubly-fed generator (DFIG) of 11 kW. The published works dealing with this type of wind turbine models work mostly with wound rotor generator on two axes that ignore th...
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| Tipo de recurso: | tesis doctoral |
| Fecha de publicación: | 2016 |
| País: | España |
| Institución: | Universitat Politècnica de València (UPV) |
| Repositorio: | RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia |
| Idioma: | español |
| OAI Identifier: | oai:riunet.upv.es:10251/62689 |
| Acceso en línea: | https://riunet.upv.es/handle/10251/62689 |
| Access Level: | acceso abierto |
| Palabra clave: | Generador doblemente alimentado Sincronización Hueco Reactiva INGENIERIA ELECTRICA |
| Sumario: | [EN] This work begins in a laboratory of the Instituto de Ingeniería Energética (IIE) of the UPV to launch a wind simulator with a doubly-fed generator (DFIG) of 11 kW. The published works dealing with this type of wind turbine models work mostly with wound rotor generator on two axes that ignore the iron losses. This paper presents an equivalent circuit model for the steady state study considering the losses in the stator iron and iron losses variables rotor is proposed. These losses are significant in small machines, which power are less than 30 kW [22]. It is found that the equivalent iron loss resistances can be located either in parallel to the magnetizing reactance, or in circuit terminals. The model allows having a practical expression to the electromechanical power. An iterative procedure is proposed for the generated electric power. The procedure uses known models of wind turbines from scientific literature. Reactive power consumed by the stator to optimize the efficiency of the wind turbine is obtained, which allows determining the appropriate battery capacitors for these machines. It is noted that the connection of this battery to the stator before connecting to the grid can improve the synchronization because reduces the required rotor voltage. An alternative synchronization method first connects the stator to the grid, then allows the current to stabilize and finally connects converter. This method is useful for prototyping simulators because it allows operating the switch that connects the stator to the grid manually. Electronic converter switches act faster than a conventional switch, which, for synchronization with a strong changing wind, may be advantageous for small wind turbines with low inertia. An advantage of these generators is the use of reduced power converters (approx. 1/3 of the generator electric power), Li [27]. The proposed model determines the maximum speed of the generator that provides greater efficiency with an adequate power converter. Converter electronic components are very sensitive to over currents and over voltages. Therefore a controller that prevents operation in extreme conditions is required. These types of conditions are presented in the transients and the proposed dynamic models allow analyzing the most common transients in wind turbines. The generator dynamic model also includes the iron losses by equivalent resistances at the terminals of the circuit, which links to the steady state model which determines the initial conditions. In dynamic calculations conversion factors designed to simplify power calculations are used. A simple direct power control regulator model is proposed. It uses the targets of stator active power (Ps*) and stator reactive power (Qs*). This model with the other proposed dynamic models using Simulink (Matlab) allows analyzing the behavior under various conditions of normal operation: connection of converter with stator open, synchronization, synchronization to MPP transition or wind variation. The E.ON.Netz 2006 standard is compared with the procedure of Resolution 4/10/2006 12.3 of the General Secretariat of Energy and the response to a voltage sag is analyzed. The assembled prototype simulator consists of an induction motor squirrel cage and wound rotor generator, both of 600 W. The motor that simulates the turbine is fed with a variable frequency drive. A custom inverter has been developed to feed the generator rotor that is powered directly from the DC bus of the variable frequency drive and, therefore, a regenerative rectifier is not required. The prototype which incorporates five current sensors, three voltage sensors and a quadrature encoder with index has allowed verify some of the results obtained with the models presented. |
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