Single-Phase UPC with Lithium-Ion Battery System

This paper proposes a new Direct DC-link voltage controlled single-phase Universal Power Compensator (UPC) in combination with Lithium-ion cell bank system. UPC not only handles the power quality issues related to current and voltage but also takes care of power interruption with an auxiliary supply system consisting of lithium-ion cells. The lithium-ion cells available may be from another system (like electric vehicles or any other system) or available as a dedicated source can be utilized affectively with the UPC system. The two compensators (for current and voltage compensation) of UPC system are equally allowed to handle the power rating from the common connected secondary source to the load, which is assumed to be a sensitive and emergency load. Since the load is sensitive, any kind of voltage disturbance from the supply side in the form of sag and swell is taken care of by the series compensator. Moreover, the shunt compensator takes care of the harmonics being introduced by the non-linear loads, to maintain the source side power quality in terms of keeping the source current THD below 5 %. The two compensators are also utilized equally to deliver the power from secondary source (Li-ion cells) to the emergency load, in case of source interruption, with a special arrangement of the configuration. The analysis of the proposed single-phase UPC system is carried out for different operating conditions using MATLAB/SIMULINK.