A motor control device that controls driving of a first inverter and a second inverter each configured to control a supply current to a three-phase alternating-current motor. The motor control device is configured to: switch a control mode between a single-inverter control mode in which one of the first inverter and the second inverter is driven to control the supply current to the motor, and a twin-inverter control mode in which both the first inverter and the second inverter are driven to control the supply current to the motor; calculate each of a first power loss due to the single-inverter control mode and a second power loss due to the twin-inverter control mode; and set the control mode to the first power loss or the second power loss, whichever has a smaller power loss.

An energy assembly includes: an engine including a crank shaft; a starter that starts the engine; an energy converter that is connected to the crank shaft of the engine and converts rotational power of the crank shaft into another type of energy; controlling circuitry configured to control the engine, the starter, and the energy converter; a supporting body supporting the engine, the starter, the energy converter, and the controlling circuitry; and an energy interface that transmits the energy, generated by the energy converter, to an external device detachably attached to the energy assembly. The engine, the starter, the energy converter, the controlling circuitry, and the energy interface are integrated with each other.

An energy assembly includes: an engine including a crank shaft; a starter that starts the engine; an energy converter that is connected to the crank shaft of the engine and converts rotational power of the crank shaft into another type of energy; controlling circuitry configured to control the engine, the starter, and the energy converter; a supporting body supporting the engine, the starter, the energy converter, and the controlling circuitry; and an energy interface that transmits the energy, generated by the energy converter, to an external device detachably attached to the energy assembly. The engine, the starter, the energy converter, the controlling circuitry, and the energy interface are integrated with each other.