Transient Behaviour of Double-Conversion On-Line UPS Systems Powering Multiple Load Transformers

Numerous industrial facilities involve the installation of load transformers with their respective loads. As these loads are engaged or dis-engaged, their transformers are also connected and dis-connected. A transient current which typically occurs when the transformer is switched-in, can easily be observed for double-conversion on-line UPS systems feeding such load transformers. This paper investigates the transient behaviour of conventional double-conversion on-line UPS systems and proposes a current control strategy to eliminate the possibility of any transient inrush current during switching-in of multiple load transformers. The current control scheme is validated by the simulation results. MATLAB is used to obtain simulation results.This research was supported by BK21PLUS program through the National Research Foundation of Korea funded by the Ministry of Education