Nouvelles Architectures Electriques Optimisées de Générateurs Photovoltaïques à Haut Rendement - New Optimized Electrical Architectures of a Photovoltaic Generators with High Conversion EfficiencyAloña Berasategi Arostegi
This thesis focuses in the optimization of the efficiency of photovoltaic power conversion chain. In this way, different improvements have been proposed in the electrical architecture and its control algorithms in order to obtain high efficiency in a large rage of input power and long life-time of PV power conversion system. Using loss analysis, the benefits and drawbacks of parallel connection of power structures has been shown. This analysis has allowed the conception of a new optimized architecture constituted by parallelized power converters, called Multi-Phase Adaptive Converter (MPAC). The singularity of these power structures consists on the adaptation of the phases of the converter depending on the power production in real-time and looking for the most efficient configuration all time. In this way, the MPAC guarantees high conversion efficiency for all power ranges. Another control law is also implemented which guarantees a rotation of the phases to keep their working time uniform. Thus, the stress of the components of all the phases is kept homogenous, assuring a homogeneous aging of the phases. Since the global stress of the component is lower, the MPAC presents a longer life-time. The improvements in the power conversion stage are shown by experimental prototypes. Experimental tests have been done for global validation. Comparison with a classical power conversion stage shows the improvement in the global conversion efficiency.
