Unified control of two-stage bidirectional converter with an active filter for eliminating low frequency ripple

This paper presents a bidirectional two-stage topology consisting of a boost converter connected in cascade with an inverter. In order to increase the power density is it proposed to use an active filter comprising a half bridge inverter. The control strategy proposed for the active filter eliminates the need to feedback the inverter input current, simplifying the analysis and design, enabling control by average output current and filter bus voltage. Simulations are performed in order to validate the proposed control strategy. The THD of inverter output current, power factor and the ripple at the DC link voltage are analyzed.