State-Space Averaged Model of Three-Phase Four-Wire Shunt Active Power Filter Based on Current-Controlled VSI

Abstract

This work presents a universal state-space average model of three-phase four-wire shunt active power filter based on current-controlled voltage-source inverters. In this type of inverters two topologies are commonly used, namely the Four-Leg Full-Bridge (FLFB) topology, and the Three-Leg Split-Capacitor (TLSC) topology. Combining these topologies, a third topology can be obtained, namely the Four-Leg Split-Capacitor (FLSC) topology. This last topology exhibits very interesting characteristics for active filter applications. By means study of FLSC topology a state-space average model can be obtained, which will allow long-time simulations with a low cost of computation time. The behaviour of FLFB and TLSC converters can be obtained as particular cases of this universal model. Likewise, a generic technique for injected current control is proposed, offering as main advantage a decoupled control of the different legs, so full-bridge converters can be implemented without using space-vector based current control techniques.