1-MHz High-step-up Converter with Switched Inductors Based on Optimized Integrated Magnetics

A 1-MHz single-switch high-step-up converter with switched inductors is proposed, 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 is added to achieve high voltage gain. The proposed converter works in discontinuous conduction mode (DCM) to realize soft switching. In addition, the switch adopts wide-bandgap semiconductor gallium nitride (GaN) to obtain better high-frequency performance. To further increase efficiency, magnetic integration technology is used to achieve structural integration of the three inductors. An optimized scheme based on a commercial core is determined according to simulation and calculation results. Operational principles and parameter design process are introduced in detail in this paper. A 1-MHz, 200-W prototype operating in DCM with a voltage gain exceeding 13 times has been designed to verify the theoretical analysis. Measured efficiency reaches up to 94.3% at full load.