A 1-MHz switched-inductor-based high-step-up converter with optimized integrated magnetics

In this paper, a 1-MHz switched-inductor-based single-switch high step-up converter is proposed which is suitable for high-voltage applications. On the basis of a conventional single-ended primary inductor converter (SEPIC), a switched inductor cell with a pump capacitor and a voltage multiplier unit are added to achieve high voltage gain. The proposed converter works in discontinuous conduction mode (dCM) to realize soft switching. In addition, the switch adopts the wide-bandgap semiconductor gallium nitride (GaN) to obtain better high frequency performance. In order to further increase the efficiency, the magnetic integration technology is used to achieve the structural integration of the three inductors. Optimized scheme based on commercial core is determined according to simulation and calculation results. The operational principle and parameter design process are introduced in detail in this paper. A 1-MHz/200-W prototype with more than 13x voltage gain in DCM has been designed to verify the theoretical analysis. The measured efficiency was up to 94.3% at full load.