This work proposes an innovative control approach for an isolated DC-DC converter tailored to DC grid applications. The architecture employs a cascaded choppers DCDC (CC DC-DC) topology, in which an auxiliary converter, comprised of a series connection of chopper stages, is integrated on the primary side of the transformer within a three-phase dual active bridge (TP-DAB) configuration. The purpose of the auxiliary converter is to reduce RMS and peak currents caused by the reactive current. The introduction of phase-shift between the primary and secondary bridges to the CC DC-DC converter allows for an increase in the switching frequency, which in turn improves the controllability of the system. The basic operation and control strategy of the proposed converter are presented followed by a comparison of RMS and peak currents. The effectiveness of the proposed approach was validated through experiments conducted on a 5.5 kW prototype system operating at 150 V. © 2025 IEEE.

This paper focuses on the implementation of output power feedback control for a non-isolated dc-dc converter with a single auxiliary chopper circuit, intended for railway applications. The conventional chopper circuit typically requires large and heavy inductor to reduce current ripple, which is undesirable on-board moving train cars. To solve this problem, this paper proposes a non-isolated dc-dc converter with a single auxiliary chopper circuit, which transfers power using a triangular ac inductor current, allowing the inductor mass and volume to be reduced. This paper presents the basic operation principles and a control method that regulates output power using feedback control. Simplified theoretical expression of the output power is derived and verified through comparisons with both simulation and experimental results. Furthermore, the proposed control method is validated using a downscaled experimental setup, where the output power was observed to be stable under dynamic conditions. © 2025 IEEE.