PROJECT TITLE :

A High Step-Down Isolated Three-Phase ACDC Converter - 2017

ABSTRACT:

In this paper, one-stage 3-section isolated ac-dc converter topology utilizing SiC MOSFETs is proposed for power rectification with a stepped-down output voltage. Unlike the conventional two-stage [front-finish power factor correction (PFC) stage and isolated dc-dc stage] ac-dc converters, the complete/half bridge structure in dc-dc stage is eliminated during this structure. The high-frequency pulsating voltage is obtained directly from the PFC stage and is applied across the high-frequency transformer, resulting in a additional compact style. Yet, there is a plus of zero voltage switching (ZVS) in four PFC MOSFETs connected to the high-frequency tank, which is not achievable in the case of a typical two-staged ac-dc converter. A sine-pulse width modulation (PWM)-primarily based control scheme is applied with the common-mode duty ratio injection methodology to attenuate this harmonics without affecting the facility factor. An LC filter is used after the PFC semistage to suppress the line-frequency voltage ripple. Furthermore, the intermediate dc-link capacitor value can be greatly reduced through no extra ripple constraints. Experimental and simulation results are included for a laboratory prototype, that converts a hundred and fifteen-V, 400-Hz 3-phase input voltage to 28-V dc output voltage. The experimental results demonstrate an influence issue of zero.993 with a conversion potency of ninety five.four%, and total harmonic distortion (THD) as low as 3.fivep.c at 2.1-kW load condition.