This application discloses an energy conversion apparatus, a power system, and a vehicle. The energy conversion apparatus includes: an inductor (12), where an end of the inductor is connected to an external charging port (2); a bridge arm converter (13), connected between an external battery (3) and the external charging port (2), where the bridge arm converter (13) includes a first phase bridge arm (131), a second phase bridge arm (132), and a third phase bridge arm (133) connected in parallel, and the other end of the inductor (12) is connected to the first phase bridge arm (131); a voltage transformation unit (14), where an input end of the voltage transformation unit is respectively connected to the second phase bridge arm (132) and the third phase bridge arm (133); and a first bidirectional H-bridge (15), connected between an output end of the voltage transformation unit (14) and the external battery (3).