Common-Ground-Structured High-Reliability Single-Phase AC-AC Converters

This article proposes enhanced single-phase pulsewidth modulation buck, boost, and buck-boost-type ac-ac converters. The proposed converters, in which input and output voltages share a common ground, require no isolated voltage sensor and have no leakage current problem. The commutation problem is solved with series-connected switching cell structures without using a resistor-capacitor snubber. In addition, switching patterns are determined using only the polarity of input voltage, allowing the inductor currents to flow through switching devices during all operational modes. Because two switches are always turned on during a half-period of the input voltage, the switching loss is significantly reduced. Detailed analysis and experimental results are provided to verify the performance of the proposed converter.