Tesis doctoral de Raul Santiago Muñoz Aguilar
The control of the stand-alone the wound rotor synchronous generator has been analyzed in this dissertation. For this islanded configuration, the mechanical speed determines the frequency, and the rotor voltage is used to set the stator voltage amplitude. Due to the electrical time constant is so fast compared with the mechanical time constants, the mechanical speed was considered constant and externally regulated and the research was focused on the stator voltage amplitude regulation. four different controllers based on sliding mode control techniques were designed in the dq reference frame. The obtained control laws regulate the stator voltage amplitude irrespectively of the load value. Furthermore, only voltage and rotor position measures (to compute the dq transformation), are required. The stability of the obtained equilibrium points was proved at least using small-signal analysis. simulation and experimental validation of each controller containing several scenarios were carried out. The obtained results validate the designs and show the main advantages and disadvantages of each closed loop system. chapter 2 covers the modeling issues of the wound rotor synchronous machine. From the general three-phase dynamical equations, and using the park transformation, the dq-model of the stand-alone wound rotor synchronous generator feeding both a resistive and an inductive load are obtained. Equilibrium points of the obtained systems are analyzed and, after defining the control objective, the desired equilibrium points are computed. finally, linear approximated models are obtained and their transfer functions are also presented. pi controllers are the most used in the industry because they offers good performance and are easily implementables. In chapter 3 we obtain the tuning rule for the pi controller, and we analyze these results in order to propose new controllers which improve the classic pi approach. the sliding mode control scheme for the wrsg connected to a resistive load is designed in chapter 4. It also includes a complete stability analysis of the closed loop system. chapter 5 presents two sliding mode designs to regulate the stator voltage amplitude for a stand-alone wound rotor synchronous generator. Both use the stator voltage d-component error in the switching function. The first case is a nested controller, where an outer pi loop is added to provide the proper d-voltage component reference. In the second approach an integral term is added to the switching function. the case of feeding an inductive load is studied in chapter 6. The controller introduces a dynamic extension because the stator voltage amplitude is a zero relative degree output. As result, a robust controller, which neither depends on the machine parameters nor on the load values, is obtained. in chapter 7 the simulation and the experimental results of the designed controllers for the stand-alone wound rotor synchronous generator are presented. Firstly, a complete description of the bench is provided. It also includes details of the data acquisition stage and the used dsp card. Secondly, the description of the simulation procedure is commented. Then, the simulation and experiments which contains several scenarios, with reference change and load variations evaluated for each controller are presented.
Datos académicos de la tesis doctoral «Sliding mode control of the stand alone wound rotor synchronous generator«
- Título de la tesis: Sliding mode control of the stand alone wound rotor synchronous generator
- Autor: Raul Santiago Muñoz Aguilar
- Universidad: Politécnica de catalunya
- Fecha de lectura de la tesis: 19/07/2010
Dirección y tribunal
- Director de la tesis
- Enric Fossas I Colet
- Tribunal
- Presidente del tribunal: domingo Biel soé
- Emilio José Bueno peña (vocal)
- vadim Utkin (vocal)
- Javier Poza lobo (vocal)