This digest presents a novel integrated multidirectional three-port DC/DC converter with a high step-up ratio for high-voltage bus-based DC microgrid systems. The converter topology employs primary-side pulse width modulation plus secondary-side phase-shift control, resulting in a highly integrated design. By achieving extended Zero-Voltage-Switching (ZVS) in all MOSFETs, the converter exhibits reduced switching losses and increased efficiency. The active voltage quadrupler rectifier structure reduces voltage stresses on the secondary-side components, while the interleaving structure reduces current ripple in the PV panel. A 500-W prototype is designed and validated through experimental results, confirming the converter's performance.