Abstract: Charging power supply based on AC-link has the advantage of high power density and can be used for primary energy source of high-power microwave (HPM) system. In order to meet the requirement of high power density, a three-phase AC/AC converter based on AC-link parallel resonance is studied. Topological structure and operating principle of the converter is analyzed, the specific working process of 16 modes and the realization of soft-switching are described and the algorithm of switches on time is given. A 15 kW simulation platform is built and energy conversion processes under different loads are analyzed. The result shows that the conversion of voltage and frequency is realized, currents of both sides are sinusoidal, also, unity input power factor and zero voltage switching(ZVS) are realized.