Enhanced Three-Phase Shunt Active Power Filter Interfacing a Renewable and an Energy Storage System

This paper presents an enhanced three-phase shunt active power filter (SAPF) that, besides its inherent functionalities of power quality problems compensation, also allows the interface of a renewable energy source (RES, namely solar photovoltaic – PV panels) and an energy storage system (ESS, namely batteries) through its dc-link. On the power grid-side, a three-phase four-wire voltage-source ac-dc converter is connected with the power grid, operating as an SAPF, whereas the RES-interface and the ESS-interface are made through a three-port multilevel dc-dc converter connected to the dc-link of the SAPF. Besides, to compensate power quality problems related to currents, the SAPF also permits the controllability of the bidirectional power exchanged between the power grid and the dc interfaces, i.e., the RES and the ESS. The operation principle of the whole system, as well as the detailed control algorithms, are described in the paper. A validation was performed through computer simulations, where it is possible to analyze the different operation modes of the enhanced SAPF interfacing a RES and an ESS through the dc-link.