Analysis of dual-inductor hybrid converters for extreme conversion ratios

This article presents a dual-inductor hybrid (DIH) converter that is capable of efficient nonisolated dc-dc conversions with extremely large voltage conversion ratios. The converter topology combines a switched-capacitor network and two interleaved inductors, which supports simple duty-cycle control for output regulation. In order to achieve complete soft charging for all flying capacitors, a method to optimally size the capacitors has been proposed and verified. Detailed analysis of the two inductor currents revealing a new and simple method to modulate them and its impacts on output regulation and efficiency are also provided and demonstrated in experiments. Employing the converter topology and design methods, a DIH converter prototype is implemented and measured for a wide range of operating voltages, providing a 1-2-V output from a 48-V input and a 1-5-V output from a 150-V input with output currents up to 20 A. The converter achieves 94.3% peak efficiency at 48 V-to-2 V/7 A conversion and 93.7% at 150 V-to-5 V/18 A conversion.