High frequency inverter circuit for UPS systems

In this paper an On-Line UPS system is proposed. The traditional inverter in the double conversion On-Line UPS system is replaced with a high frequency inverter so that the size and hence the performance of the UPS is improved. The input as well as the output frequencies of the proposed UPS is still 50 Hz, however the internal operating frequency of the UPS inverter is higher than 50Hz. The challenge in this proposed circuit is to keep the 50 Hz go through the transformer windings without altering the transformer high-frequency design. The results presented in this paper are shown at 500 Hz and this is mainly to demonstrate the idea. However, a much higher frequency can be used.