La conception de méthodes permettant de réduire le volume d'un convertisseur de puissance dédié aux centrales photovoltaiques

Abstract

The market for photovoltaic systems has experienced a very high growth rate in recent years. This growth is mainly due to photovoltaic systems linked to the electricity distribution network. The disparity of voltage levels and currents between the sources (photovoltaic panels) and the electricity distribution network obviously requires high performance power converters. The technical performance and reliability of converters are parameters that can significantly affect the production of electrical energy, the profitability and the financial costs of a system. These facts led to an international race for low profile power converters, which exposed several limitations to the use of conventional magnetic component structures. This last structure takes a volume of 70% in the power converter, which makes the integration of passive components an inevitable solution. The objective of this thesis is to design power converters with very small sizes dedicated to the photovoltaic system by designing low profile magnetic passive components (inductor). The work started with the implementation of the design and the dimension of the planar inductor model to be integrated in the DC-DC Boost converter, taking into account the specified space, which must not be exceeded. Following a comparison of planar coils of different shapes, we opted for the square geometry. This coil has been improved to take advantage of mutual inductance. Thus, we designed a dual-layer inductor. In-depth studies were carried out in order to opt for the optimal conductor thickness and the width of the gap. These parameters are two very disturbing elements and generate significant energy losses. It should be noted that the thickness of the conductor was neglected by the literature and does not appear in any formula to the calculation of the inductance value. The design of an equivalent circuit of the dual-layer inductor has validated its correct operation and that of the converter which contains it. To correct the drop in the converter’s output voltage, we designed an MPP block that keeps it constant. This block MPP, allowed us to designed a smart converter which stabilizes automatically, its output voltage whatever the input voltage coming from the PV module. The study of electromagnetic and thermal behaviour is an essential operation in designing of our dual-layer inductor. The results obtained by different simulation using COMSOL Multiphysics confirmed that a very thin conductor thickness and too narrow gap between the two stacked coils of the dual layer inductor are not recommende