Minimum-Output-Current-Ripple Control of Current-Fed Three-Level Phase-Shift Full-Bridge Converter

Electrified ports using medium-voltage DC (MVDC) renewable energy microgrids require current-fed dc/dc converters in application scenarios such as battery or ultracapacitor charging units and hydrogen production systems. This paper designs a three-level phase-shift full-bridge (TL-PSFB) converter that interfaces with the MVDC microgrid. Its operation current source mode requires wide output voltage range small ripple. Firstly, dual-output TL-PSFB topology is introduced, principle of pulse width modulation (PS-PWM) presented. Secondly, traditional constant-conduction-duty-cycle (CCDC) strategy analyzed. Then, minimum-output-current-ripple (MOCR) proposed by analyzing relationship between ripple, conducting-duty cycle, duty constant control combined MOCR designed. The ripple smaller than CCDC full operating conditions. Under same design index, value loss filter inductor can be reduced strategy. In addition, widen regulation increase bus utilization without causing significant changes to total harmonic distortion (THD) primary voltage. Finally, experimental results verify correctness theoretical analysis.