Phase Shedding Impact of Dc-Dc Interleaved Converters in the Efficiency of a Multistring Photovoltaic System

As grid-connected photovoltaic systems gain visibility, scientific efforts are oriented to efficiency maximization. On this regard, a widely used configuration is the multistring one. Although its characteristics made it suitable for high efficiency applications, these characteristics can be better improved by the use of dc-dc interleaved power converters operating in discontinuous conduction mode (DCM). Moreover, depending on solar resource availability, the system performance can be improved by changing the amount of active phases when the delivered maximum power changes. This strategy allows to reduce semiconductor losses but it may increase the dc-link ripple. In this sense, this paper presents the analysis of the phase shedding impact of dc-dc interleaved converters on the efficiency of multistring photovoltaic systems, by the evaluation of particular cases.