MPPT for photovoltaic systems using Fractional Power Processing Architecture

Abstract

This study presents a novel investigation, with conceptual contributions, into how a fractional power processing (FRPP) architecture can be used to track the maximum power point of a photovoltaic (PV) system while using PV modules as the auxiliary source. Two configurations are proposed for fractional power processing within the photovoltaic system. The first, referred to as coupled FRPP (CFRPP), utilizes only photovoltaic modules as the auxiliary energy source, with direct connection to a converter. The second, referred to as decoupled FRPP (DFRPP), incorporates an energy storage system (ESS) alongside the PV modules, allowing the two PV arrays to function independently. Simulations were conducted to validate the theoretical analysis of a PV system under these two FRPP architecture configurations and to compare their performance to different power processing architectures. The results indicate that the proposed model equations are valid. It is concluded that fractional power processing enables converters designed for lower power levels to regulate the generation of higher. When applied to photovoltaic systems, both types of FRPP have demonstrated the ability to achieve maximum power while using low-power, low-complexity converters, since they are non-isolated and can even adopt simple topologies, such as buck or boost. However, each type exhibited significantly different capabilities. The DFRPP configuration demonstrates its viability by delivering superior performance compared to other power processing architectures. In contrast, the CFRPP architecture exhibits performance limitations, making it less advantageous under comparable conditions