PROJECT TITLE :

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

ABSTRACT:

In this paper, one-stage three-phase isolated ac-dc converter topology utilizing SiC MOSFETs is proposed for power rectification with a stepped-down output voltage. Not like the conventional 2-stage [front-end 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, leading to a additional compact style. Yet, there's a plus of zero voltage switching (ZVS) in four PFC MOSFETs connected to the high-frequency tank, which isn't achievable within the case of a conventional two-staged ac-dc converter. A sine-pulse width modulation (PWM)-based control theme is applied with the common-mode duty ratio injection technique to reduce the current harmonics without affecting the ability factor. An LC filter is employed after the PFC semistage to suppress the road-frequency voltage ripple. Furthermore, the intermediate dc-link capacitor price can be greatly reduced through no additional ripple constraints. Experimental and simulation results are included for a laboratory prototype, that converts a hundred and fifteen-V, four hundred-Hz 3-section input voltage to 28-V dc output voltage. The experimental results demonstrate an influence issue of 0.993 with a conversion efficiency of ninety five.fourpercent, and total harmonic distortion (THD) as low as three.five% at a pair of.1-kW load condition.