This paper proposes a high current direct three-phase AC-DC rectifier with high-frequency transformer isolation configured as open-delta. The three-phase input voltages are modulated by two AC to AC converters to generate a high-frequency link at 20 kHz. The high-frequency link is then interfaced to two three phase rectifiers configured in 12-pulse by means of a high-frequency open-delta transformer arrangement. A phase shift modulation is introduced to achieve zero voltage switching and to regulate the output DC voltage. The overall three-phase input currents are of high quality and near unity power factor due to the cancellation of 5th and 7th harmonics. Derivation of a new small signal model of the converter is discussed for the design of DC closed loop. Preliminary results demonstrate the validity of the concept.
