Dissertação
Metodologia de otimização de conversores estáticos com paralelismo de células boost aplicado à célula a combustível
Fecha
2019-02-28Autor
Bridi, Éder
Institución
Resumen
This thesis presents an optimized design methodology for non-isolated static converters with Nboost
cells in parallel, that process energy between a renewable energy source and a DC bus. The
method scans for the best solution in view of the maximum efficiency for the minimum volume.
It combines distinct technologies and cell numbers and picks a set of solutions in accordance to
the preselected discrete parameters range for each operation point, which is described by three
parameters ( IL@fs@J). It also searches in databases for the components in which the arrangement
leads to the best performance regarding the design requirements. Among the possible
solutions, the method chooses the solution that yields the maximum efficiency and/or the minimum
volume for the continuous conduction mode as well as for the discontinuous conduction
mode. Thus, it is possible to design converters with high efficiency and reduced volume for high
static gain applications. This study also presents the components modeling and the converter
static gain curves, considering parasitic resistances and their impact. By identifying the parameters
that prevent converters, as simple as a boost converter, from achieving high static gain,
it is possible to apply techniques that mitigate the impact of these undesired effects, allowing
converters to operate closer to their ideal static gain. The input and output filter design of the
converter reflects the dynamic behavior of a fuel cell, making it possible to reduce its volume
and to increase its efficiency without hindering or damaging the power supply operation. As
auxiliary tools to design a project and to understand the results, in this proposal, the behavior
of the input and output currents and the impact that they produce on the output converter
voltage are analyzed. By selecting the adequate number of cells and the operation mode, it is
possible to find operation conditions where the current ripple is drastically reduced. As a result,
the filtering capacitors can be significantly reduced and there is also the possibility of reducing
the inductor size irrespective of the operation mode used.