Single-phase shunt active power filter with UPS operation using a bidirectional Dc-Dc converter for energy storage interface

This paper presents a single-phase shunt active power filter (SAPF) with bidirectional dc-dc converter for uninterruptible power supply (UPS) operation. The proposed system comprises two power converters, namely a dc-ac converter to interface the power grid and a bidirectional isolated dc-dc converter connected to a battery pack, with both converters sharing the same dc-link. The arrangement of the converters allows the operation of the system in three different modes: (1) As SAPF, during normal operation; (2) As off-line UPS, in case of power grid outages; (3) As battery charging system, combined with the operation as SAPF. Simulation results of these three modes are presented in the paper to prove the operation feasibility of the proposed system. A reduced-scale prototype was developed, and the main parameters of the control stage, as well as the implemented control algorithms and power structure, are described in the paper. The experimental results obtained highlight the main benefits of the developed prototype.