A novel phase-shift full-bridge DC-DC converter using Magneto-rheological fluid gap inductor

Conventional phase-shift full-bridge converters use high leakage inductance of transformer to achieve ZVS over wide load range of converter. But high leakage inductance causes drawbacks such as high circulating current, reduced voltage gain, severe voltage spike and parasitic ringing of secondary rectifier diode. So, phase-shift full-bridge converter using saturable inductor is usually used to solve drawbacks of conventional converter. Although use of saturable inductor solves drawbacks of phase-shift full-bridge converter, but reduced core size to get good performance causes high core temperature at high current due to increased core loss. This paper proposes a phase-shift full-bridge converter using MR(Magneto-rheological) fluid gap inductor which has advantages over conventional phase-shift full-bridge converters. MR fluid gap inductor has variable inductance characteristic caused by changing inductor current. Structure of MR fluid gap inductor and its properties were analyzed by using reluctance model. The principle, implementation and performance of the phase-shift full-bridge converter using MR fluid gap inductor are investigated to verify converter performance compared with conventional phase-shift full-bridge converter and phase-shift full-bridge converter using saturable inductors.