In this embodiment of this application, the battery 301 is similar to the battery 101 in the foregoing embodiments corresponding to FIG. 1, and details are not described herein again.

In this embodiment of this application, the three-phase bridge arm converter 302 may be specifically a three-phase three-bridge-arm converter, a three-phase four-bridge-arm converter, or the like. This is not limited in this embodiment of this application. For example, when the three-phase bridge arm converter 302 is a three-phase three-bridge-arm converter, the three-phase bridge arm converter 302 includes three bridge arms, and each bridge arm may be two switching transistors connected in series. A port for connecting the three bridge arms in parallel is the direct current port of the three-phase bridge arm converter 302, and is configured to connect to a direct current device. In this embodiment of this application, the direct current port of the three-phase bridge arm converter 302 is connected to the battery 301. Intermediate end points of the three bridge arms are three alternating current ports of the three-phase bridge arm converter 302, and are configured to connect to the motor winding 303. When an alternating current passes through the motor winding 303, a corresponding motor is driven.

In some embodiments, a switching transistor used for the three-phase bridge arm converter 302 may be a transistor connected to a diode in parallel, a metal-oxide-semiconductor field-effect transistor (MOSFET), an IGBT, or the like. This is not limited in embodiments of this application.