Analysis, modeling, control and operation of an interleaved three-port boost converter for DMPPT systems including PV and storage at module level

This paper presents the analysis, control and implementation of the interleaved three-port boost converter. The scope of this paper is the interfacing of photovoltaic systems that include storage. A new symmetrical PWM modulation strategy that prevents unwanted switching states without requiring external circuitry is presented. This modulation allows for proper sampling of the measurements, increasing thus their accuracy. Large- and small-signal models of the interleaved and non-interleaved three port boost converters are presented and transfer functions are derived for control design purposes. The different currents in the converter are controlled using control loops that govern the behavior of the converter. These loops are intuitively designed by treating them independently. With the proper loop bandwidth selection, the converter achieves fast response and good reference tracking and is suitable to interface photovoltaic and storage systems with different kinds of loads. The presented models, modulation and control loops are validated through simulation and with experimental results.