Modeling and Control of Grid-Connected Photovoltaic Power Plants utilizing a Simplified Model of the Modular Multilevel Converter

The intent of this paper is to implement a simplified model for a modular multilevel converter (MMC) to be used as an interface between a photovoltaic power plant and the ac grid. MMC-based topologies as well as photovoltaic (PV) arrays feature a large number of components, and therefore difficult to be simulated in detail. Because of this, researchers have developed simplified models for both the MMC and PV arrays to account for their terminal behavior. This paper makes use of terminal behavioral modeling techniques for MMCs and PV arrays proposed in the literature, developing a full model for a single-stage grid-connected PV power plant. The paper demonstrates via computer simulations the ability of the MMC to perform maximum power point tracking while injecting adjustable reactive power, similar to that of conventional two-level voltage source converters.