Three-phase Flyback-Boost DC-DC converter with three-phase high frequency isolation

This paper presents a new modulation strategy of the three-phase DC-DC Boost converter with high frequency isolation. This work has as its main objective to present a solution to deal with the forbidden region found in the study of the referred converter. The proposed modulation keeps the main characteristics of the original topology, which are: the voltage and current frequencies in the output filter are three times the switching frequency, input current ripple reduction, high frequency isolation, moreover, when the converter works within duty ratio up to 1/3, it makes it possible to precharge the output capacitor, reducing the start-up converter´ currents. A theoretical analysis of the operating stages and the experimental results are presented to a prototype operating as a Flyback-Boost with switching frequency of 20 kHz, input voltage from 24 V to 120 V, output voltage from 52 V to 450 V and output power from 650 W to 2025 W.