Predictive control for an asymmetric multilevel converter for PV energy injection

Recent publications on multilevel converters show different topologies and control to obtain an improvement in the sinusoidal current waveform, controlling de DC voltage and the active/reactive power. This paper presents a 27-level asymmetric multilevel converter for photovoltaic injection using a predictive control algorithm that commands the three-phase converter to control the active power injected to the grid. The analyses include the detailed description of the converter valid states as well as the discrete time model of the equivalent circuit. The control strategy considers a master linear controller in charge to track the Maximum Power Point and a slave loop that includes a predictive controller, which is responsible of the current tracking. The proposal is validated through simulated results that illustrates the dynamic behavior of the converter under irradiance changes.