Improved EPS-Based Robust Dynamic Control of Constant Current Source-Based Isolated Dual-Active-Bridge dc–dc Converter with Reduced Current Stress.

Due to its attractive features of bidirectional power flow, zero-voltage switching (ZVS), high power density, and electric isolation, the current source-based isolated dual-active-bridge (IDAB) dc–dc converter is widely employed in various renewable energy applications. Efficacy and sublime dynamic performance are two primary control objectives for IDAB-dc–dc converter. Recently a single-phase shift-based fast current controller (SPS-FCC) was proposed to enhance the dynamic performance of the IDAB-dc–dc converter. However, this control technique suffers from high current stresses when the voltage ratio between two bridges deviates from 1, which can affect the overall efficiency of the converter. A typical extended-phase shift (EPS) control scheme can substantially improve the converter efficiency by minimizing these current stresses, but it cannot meet the robust dynamic response requirements. To overcome the drawbacks of SPS-FCC and EPS, this study proposes a novel EPS-based fast current controller for current source-based IDAB-dc–dc converters (EPS-FCC). The proposed control strategy combines the high efficiency of EPS and the robust dynamic performance of FCC. Thus, the IDAB-dc–dc converter implemented with the proposed control technique has the advantages of excellent dynamic response and high efficiency under light load conditions. Moreover, the proposed controller is cost-effective compared to SPS-FCC as for the same transmission power, the electric equipment with low current ratings can be selected. To confirm the effectiveness of the proposed control scheme, a 300 W IDAB-dc–dc converter prototype is developed. Different test cases are designed, and the proposed control technique is compared in detail with SPS-FCC and EPS control schemes under these test cases. The experimental results have validated the effectiveness of the proposed control technique. [ABSTRACT FROM AUTHOR]