Unified control design approach applied to four-wire shunt active power filter topologies

This paper presents a unified control design approach involving four topologies of shunt active power filters (SAPF), which can be applied to three-phase four-wire distribution systems. The SAPF structures are deployed by means of the following inverter topologies: full-bridge composed of three modules, four-legs, split-capacitor and neutral point clamped. The SAPFs are compared to each other through detailed theoretical studies, resulting in mathematical models that can properly represent each topology. After that, a generalized mathematical model that is able to represent each SAPF schemes is proposed. As a result, through of a unified control design specification, all the controller gains employed in the current and voltage control loops can be properly obtained. In order to evaluate and validate the theoretical development, simulation results are presented taking into account the SAPFs performing reactive power compensation, harmonic current suppression, as well as load unbalance compensation.