In this letter. a simple ESO based DC-link voltage control strategy was proposed for three-phase AC DC converter. With the proposed control strategy. additional sensors for improving system dynamic response under disturbance was avoided. which was suitable for “plug and play“ for expanding the UPS modules and microgrid. The proposed ESO-based DC-link voltage controller can achieve the same effect in mitigating the DC-link voltage variation with sensor-based feedforward control but has a better effect in reducing settling time. The robustness of the controller was examined in the experiment as well. The experimental results showed the effectiveness of the proposed control strategy.