A 110V/220V grid voltage on-line UPS based on High Frequency isolated four-port circuit

This paper presents a double conversion Uninterruptible Power Supply (UPS) system with input voltage equal to 110Vac/220Vac and 24Vdc battery-set. To attend these features, a four-port circuit based on High-Frequency Transformer (HFT) isolated is employed, which consists in two input ports (grid side and battery source side) and two output ports (inverter side and battery-charger side). This topology is suitable for on-line single-phase UPS systems with limited range of power applications (≤ 2kVA). Due competitive market, an opportunity to develop a new UPS with high-frequency isolation and low cost is very attractive to replace the old UPS systems isolated in low-frequency, heavy and bulky. The principle of operation and simulation results, for Vi=110Vac/220Vac; Vb=24Vdc; Vo=110Vac; So=1000VA e fo=60 Hz, are presented.