A Current-Fed Dual-Active-Bridge Integrated LC-Resonant Converter With Dynamic Power Allocating for Wide Input and Output Voltage Range Operation

Current-fed isolated bidirectional dc-dc converters (CFIBDCs) are suitable solutions for feeding batteries. However, maintaining high efficiency over wide input and output voltage (IOV) range remains a challenge for them. This article proposes a hybrid CFIBDC intended for wide IOV range operation, which is constructed by integrating a current-fed dual-active-bridge and an LC-resonant converter (LCRC). It has two power channels, i.e., a DAB-based channel and an LCRC-based channel. The DAB-based channel can achieve zero-voltage-switching (ZVS) regardless of the IOV condition. And the LCRC-based channel, which features zero-current-switching (ZCS), can share the power for the DAB-based channel, thus reducing conduction losses. By properly allocating the power between two channels, low conduction losses, full-voltage-range ZVS or ZCS, as well as low turn-off losses can be simultaneously attained over wide IOV range, thus maintaining high efficiency for the proposed converter. Meanwhile, the total device capacity is not increased compared to the state of the art. Moreover, since LCRC provides a unity voltage gain, the proposed converter is naturally voltage-matched, leading to a simplified control scheme. The effectiveness of the converter is verified by a 1.5 kW experimental setup.