Analysis of the effects of duty cycle constraints in multiple-input converters for photovoltaic applications

Abstract

A multiple-input converter for photovoltaic-powered communication sites is analyzed. The study shows that the duty cycles of a multiple-input converter, which control the power delivered by each source, may have practical limitations when each photovoltaic module attempts to achieve its own maximum power point at the same time. This paper discusses an alternative circuit that has two coupled inductors in a common output stage, which may enable the multiple-input converter to overcome the limited duty cycles. The relationship between the duty cycles and the power supplied by each input is derived mathematically in order to theoretically analyze the effects given by the limitations. Power budgeting with respect to each source is also demonstrated with simulations.