Interleaved Boost Converter for a PV Source Roberto Buerger, Rene Alfonso Reiter, Adriano Péres Universidade Regional de Blumenau (FURB) Rua São Paulo, 3250 89030-000, Blumenau – SC – Brasil aperes.furb@gmail.com Adilson L. Stankiewicz Universidade Regional Integrada - Erechim Av. Sete de Setembro, 1621 99700-000, Erechim – RS – Brasil adilsonluis@uricer.edu.br Abstract—In this paper it is presented a interleaved boost converter (IBC) for photovoltaic systems (PVS). The purpose of this converter is to transfer the low DC PV voltage to a high DC voltage at its output. The low output voltage ripple and especially the low input current ripple (for MPPT) are analyzed, verified and compared to N cell IBCs. This paper also shows to determine the critical PV current needed to work in continuous conduction mode. Finally, a 1.9kWp dual IBC is experimentally tested to verify the theoretical approaches. Index Terms--Critical Inductance, Interleaved Boost Converter, Photovoltaic System, Ripple Analyze. I. INTRODUCTION The worldwide endeavor of states to supply their population and industry with renewable energy (RE), had a big compact to the renewable energy sources like wind craft, PV an Fuel Cell. These RE sources don’t emit pollution, and can be used as a decentralized supply system. The electric energy of these sources can’t be injected directly in the national energy grid, so it is necessary to process and appropriate that voltages and currents. In the case of the PV panel, the output is a DC voltage with current source characteristics [1]. When the PV system is used local and not injecting energy to the grid, a voltage controlled converter is charging a link of batteries. For grid connected sources a frequency converter has to be added in series. The converter has to control the Maximum Power Point (MPP). In many cases the duty cycle is adjusted like the Maximum Power Point Tracker (MPPT). Almost every MPPT technique requires a low input current and voltage ripple to work appropriate. The literature shows that an interleaved technique is a good way to reduce the current ripple coming from a source [2]-[5]. The merits of the use of an interleaved technology is not only the lower input current ripple, but also a lower output voltage ripple, which can be used to reduce the DC link capacitors [2]-[5]. Many works have focused the IBC in relation of current and voltage ripple, efficiency, analyzing, simplification of small signal model, coupling and decoupling inductances [2]- [5]. This paper is focused in the analysis of the current and voltage ripple of an interleaved boost converter to a photovoltaic application. The Fig. 1 shows the proposed IBC with four commutation cells. In this application the DC link voltage is not controlled, so it varies with the duty cycle in relation to the MPPT algorithm. Figure 1. Four cell IBC II. ANALYSIS OF THE INPUT CURRENT AND OUTPUT VOLTAGE RIPPLE A. Analysis of the Input Current The IBC’s voltage and current waveforms are similar to the conventional boost converter. The difference lay in the input current and output voltage ripple. Because of the N times commutation cells in parallel, the input current and output current work with a frequency N times the switching frequency. Where N is the number of cells in parallel. The DC link is equal to the conventional boost converter, but distinguishes in the value. The following analysis is made for Continuous Conduction Mode (CCM) and all components are considered ideal, e.g. have no losses, with no ESR. The analysis depends on the duty cycle. In general the quantity of parts depends on the commutation cells are used. So exist N operations parts with its limits in D with  (for example in the four cell IBC 25 . 0 D   ). The commands to the switches are  degrees shifted.