Single-phase Delta-conversion UPS

A recently introduced reduced switch count converter family uses three switches in the legs of its single-phase, three-phase and four-leg converters. So far, the benefits and drawbacks of such converters have been widely investigated in the literature in several applications. This paper studies and proposes the single-phase six-switch converter to be implemented in delta-conversion uninterruptible power supply system. In this application the intrinsic limitations of the three-switch leg structure such as diminished dc bus voltage utilization is overcome and the attractive features of the conventional system are retained yet less number of power switches are employed. The proposed UPS enjoys integrated structure, effective performance and optimized utilization of device ratings at both series and parallel sides. The proposed configuration is presented and its control scheme and new hysteresis modulation are elaborated. The system operation is verified through simulation.