| Micro-grid systems are emerging as a means of energy cogeneration of disperse plants, such as fotovoltaics and wind. These systems are connected to the mains via a power conditioner, that is, a 3-phase inverter, and the control of the status of the 3-phase power switches is commonly carried out with classical pulse width modulation techniques (PWM) due to its simplicity. These techniques compute the status of the 3-phase power switches in a pre-established way and guarantee a unitary power factor operation of the inverter-grid system.; However, the classic PWM techniques do not guarantee high performance because of, for example, load variations, and then, they are replaced by current source vector sliding mode control computing the status for the 3-phase power switches in real time; the synchronization with the mains and the inverter management are guaranteed by applying the Park's transformation.; Three novel current source vector sliding mode control strategies are described and several simulations show the performance of the inverter control. The strategies proposed are implemented in a FPGA.; The dissertation is divided as follows: chapter 1 is for the introduction, whereas chapter 2 is devoted to the theoretical fundamentals. Chapter 3 is about the Park's transformation and chapter 4 analyses some utility observers used to synchronize in phase and frequency the 3-phase inverter with the grid by using the Park's transformation.; In chapter 5, there are shown and analized in detail three current source vector sliding mode control strategies, both in five and three levels. It is also shown the equivalence between the five and three levels control when there are no zero sequence component in the 3-phase currents. An integral regulator for the 3-phase hysteresis band is also proposed to guarantee a constant switching frequency.; In chapter 6, the plant and the controller are dimensioned in such a way that the harmonic distortions fulfil the international harmonics normatives.; In chapter 7, the current source vector sliding mode control strategies proposed are implemented digitally in a FPGA.; Finally, the conclusions of the dissertation are in chapter 8. |
