Modular Single-Stage 48-to-1-V DC–DC Converters With Output Current of 200 A

Abstract

This paper presents the concepts and results of research on non-isolated modular DC-DC converters with high voltage step-down. The results are demonstrated for the conversion ratio of 48 V to 1 V. Owing to the very high value of the output current (up to 200 A), the topology concept of the converters assumes its sharing between parallel modules. This allows for a reduction in the energy and volume of the inductors as well as resistive losses. The voltage stress of the components is also reduced. This was achieved by attaching the modules to the input voltage divider. Operation with a low duty cycle allows modules to be sequentially attached to individual input divider capacitors. This allows the use of a simple, non-isolated converter topology and ensures safe operation. Other advantages of the proposed systems are their modular design, division of load between many transistors, continuous output voltage control, self-balancing of voltages and currents, high-frequency output voltage ripple, and fault tolerance in some cases of control failure. These features are common to converters belonging to the analyzed family. The complexity of the converters of the proposed family can be optimized. However, this affects the load, voltage stress of the elements, and the efficiency of the converter. Therefore, this article presents numerous results that compare the efficiencies of several variants of the system carried out experimentally. The experimental results are presented for MOSFET-based converters with an output power in the range of 200 W and an output voltage of 1 V.