An analysis into bridgeless inverted buck-boost PFC with ZVS capabilities

Abstract

This paper proposes a buck type PFC which is based on a new bridgeless inverted buck-boost circuit. The circuit can achieve ZVS for the full range via triangular current mode (TCM) and unlike conventional buck PFC, the circuit can operate for the entire cycle. The bridgeless topology has fewer numbers of components in the conduction path than any other bridgeless boost PFC circuits. The ideal full control is discussed and a simplified control is also proposed which has almost the same efficiency with a simulated peak value of ~97.5%. This circuit also exhibits an interesting property of higher efficiencies at low load conditions which could be of interest for SMPS for laptops and computers.