High Voltage Gain Isolated DC-DC Converter for Integration in Photovoltaic Modules

Abstract

Significant cost reduction of photovoltaic system components has changed the perspective of future application of these systems. Many installation sites currently discarded due to non-optimal orientations and partial shading conditions may become economically viable. Moreover, there is a tendency for the dissemination of building integrated photovoltaic systems (BIPV). An interesting approach to maximizing the power conversion Artigo submetido em 30/05/2019. Primeira revisão em 12/08/2019. Aceito para publicação em 09/12/2019 por recomendação do Editor Marcelo Cabral Cavalcanti. http://dx.doi.org/10.18618/REP.2019.4.0042 of these systems consider using parallel arrays of integrated modules (MIC) converters. In this approach all MICs operate independently of each other providing modularity and simplicity of installation and operation. In this work is proposed using a MIC topology based on a soft-switching high-gain isolated half-bridge dc-dc boost converter for this application. This converter is analyzed in detail and is proposed a new equation to determine the static gain of this topology considering the loss of cyclic ratio caused by the presence of the auxiliary switching inductance, a methodology for designing the auxiliary inductance aiming at guaranteeing the ZVS of all switches over a wide operating range, as well as the introduction of a cascaded control scheme for parallel operation of the MIC converters. Experimental results were obtained in similar 130 W prototypes operating with their outputs connected in parallel, demonstrating the viability of the topology for the application as well as the proposed control system.