In the embodiment of FIG. 3a, when the energy conversion apparatus is in an alternating current charging mode, the first switch group 307 may be connected, and the second switch group 308 may be disconnected. After alternating current power that is input from the alternating current charging port 305 is transformed by using the transformer 304, the alternating current power is converted into direct current power by using the first switch group 307 and the two bridge arms of the three-phase bridge arm converter 302, to charge the battery 301. In addition, because the second switch group 308 is disconnected, a current on the three-phase bridge arm converter 302 does not affect the motor winding 303. When the alternating current charging port 305 is not connected to a charging pile but connected to an electric device, electric energy in the battery 301 may be converted into an alternating current by using the two bridge arms of the three-phase bridge arm converter 302, to charge/supply power to the device connected to the alternating current charging port 305. When the energy conversion apparatus is in a motor drive mode, the first switch group 307 may be disconnected, and the second switch group 308 may be connected. In this case, electric energy in the battery 301 may be transmitted to the motor winding 303 through the three-phase bridge arm converter 302 and the second switch group 308. Because the first switch group 307 is disconnected, electric energy that is input from the alternating current charging port cannot enter the three-phase bridge arm converter 302.