This paper proposes a novel PET topology combining the voltage source converter(VSC) and direct AC-AC conversion which can achieve two-stage conversion. The direct AC-AC conversion used a medium-frequency-isolation transformer replacing high-frequency transformer which can eliminate DC capacitors, so that it can reduce the system costs and simplify the control strategy compared with the cascaded H-bridge converter and MMC topologies. The topology is introduced and analysed in detail. The simulation is carried out to verify the correctness and feasibility of the topology. The direct AC-AC conversion used a medium-frequency-isolation transformer replacing high-frequency transformer which can eliminate DC capacitors, so that it can reduce the system costs and simplify the control strategy compared with the cascaded H-bridge converter and MMC topologies. The topology is introduced and analysed in detail. The simulation is carried out to verify the correctness and feasibility of the topology.