High-frequency transformer isolated 3-Φ 3-level single-stage soft-switched AC-to-DC converter

This paper presents a new 3-phase, single-stage power factor corrected, ac-to-dc 3-level converter with high-frequency transformer isolation. This converter uses capacitive output filter so that the output full-bridge rectifier diodes turn off with zero current and the turn-off voltage spikes due to high di/dt are absent. Principle of operation and different operating modes are presented with analysis. Based on the analysis design example of a 1 kW, 48 V, 50 kHz 3-phase ac-to-dc converter is presented. PSPICE simulation results for the designed converter are presented. The results show soft-switching operation and low total harmonic distortion of this converter for a reasonably wide (10% -100%) range of load.