An energy conversion apparatus, a motor, a power system, and a vehicle are provided. The energy conversion apparatus may integrate a motor drive function by using a three-phase bridge arm converter and a motor winding, and integrate an alternating current charging function by using a two-phase two-bridge-arm converter and a transformer. In this way, the energy conversion apparatus can integrate the charging function and the motor drive function. When the energy conversion apparatus is installed on an electric vehicle, a vehicle integration level can be increased, a structure layout of the electric vehicle can be simplified, and costs and a volume of the electric vehicle can be reduced.