Abstract: In view of problem of uneven loss distribution of power devices in running process of traditional neutral point clamped three level inverter, this paper introduced working principle and basic modulation strategy of active neutral point clamped three-level topology, analyzed loss characteristics of active neutral point clamped three-level converter. Active neutral point clamped three-level topology uses bidirectional power device to instead of traditional clamp diode of neutral point clamped three level, which can realize purpose of loss equilibrium of power device by selecting appropriate combination of zero voltage condition. The simulation results show that active neutral point clamped three-level topology can balance the loss of power devices, and improve the converter capacity under various typical working conditions compared with the traditional neutral point clamped three level.