Abstract: Energy storage devices in the Energy Internet require the converters with high efficiency and a wide range of output voltage. With the characteristics of soft switching and high efficiency, the LLC resonant converter has already obtained widespread applications. However, the LLC resonant converter has large output current ripples, and it is difficult to regulate the voltage at light loads, that is, it has insufficient ability to output a wide range voltage. To solve these problems, a three-phase multi-resonant converter (LLC-LC) with a wide voltage range output is proposed. To increase the gain range, an LC notch filter is introduced in each phase of the three-phase LLC resonant network. The output signals between the three phases are shifted by 120°, reducing the output capacitor current ripples and the output filter sizes. The converter has the function of automatic current sharing because of the star connection between the multi-resonant networks of each phase. The primary-side switches realize zero-voltage switching (ZVS) in the entire working range, and the secondary-side rectifier diodes achieve zero-current switching (ZCS). From the perspective of gain and efficiency, the fundamental wave analysis is used to optimize the resonant parameters of the converter, and the advantages of the converter are verified by comparing with the traditional three-phase LLC resonant converter in experiments.