High Frequency Link Type DC/AC Converter for UPS with a New Voltage Clamper

This paper proposes a new type of high frequency DC/AC converter developed for flexible, compact and high efficiency uninterruptible power supply (UPS) systems. The proposed DC/AC converter consists of a high frequency inverter, a high frequency transformer and a cycloconverter with a new voltage clamper. This cycloconverter is capable of being operated by both sourcecommutation and self-commutation (commutation by turning off the switching device). Consequently, by choosing between the two commutating methods, based on consideration and the internal voltage drop caused by commutating reactance, a commpact and efficient UPS can be realized. The voltage clamper effectively reduces power loss of the conversion system. Fabrication of a 10 kVA high frequency link type DC/AC converter is described and its loss reduction effect is demonstrated.