Improved Single-Phase AC–DC–AC Current Source Converter With Reduced DC-Link Oscillation

In this paper, a synchronization technique for single-phase ac-dc-ac current source converters is presented. The technique aims to minimize the double-line-frequency dc-link current oscillation, thus, increasing the power density of the converter. The technique is applied to an improved back-to-back crossed switches current source converter (CSC) named X-type CSC, which presents independent full quadrant operation, lower dc-link current value, higher efficiency when compared with similar ones, and high ac output voltage waveform quality. The deduction of how the dc-link oscillation is influenced by both input and output angles is presented, as well its mitigation. Simulation and experimental results of a 200-W prototype are presented in order to validate the theoretical approach, and to demonstrate the synchronization phenomenon.