Photovoltaic power control based on differential flatness approach of multiphase interleaved boost converter for grid connected applications

Abstract

A proposed parallel power converter with interleaving algorithm is chosen to boost a low dc voltage of photovoltaic (PV) to a dc bus utility level and then follows by inverter. Converters are controlled by interleaved switching signals, which have the same switching frequency and the same phase shift. By virtue of paralleling the converters, the input current can be shared among the cells or phases, so that high reliability and efficiency in power electronic systems can be obtained. In this paper, a nonlinear-control algorithm based on the flatness property of the system is proposed. Flatness provides a convenient framework for meeting a number of performance specifications on the power converter. To validate the proposed method, a prototype PV power converter (1.2-kW two-phase boost converters in parallel) is realized in the laboratory. The proposed control law based on the flatness property is implemented by digital estimation in a dSPACE 1104 controller card. Experimental results in the laboratory corroborate the excellent control scheme.