NOVELTY - The vehicle (2) has an electric motor (6) driven by output of an inverter (5). A power supply circuit (16) converts alternating current that the motor serving as a generator generates into direct current. The power supply circuit includes a transformer (12) provided with a primary coil (12a) connected to the motor and a secondary coil (12b), and a voltage regulator (15) to adjust output of the secondary coil to predetermined direct-current voltage. An inverter controller (9) is supplied with electric power from the power supply circuit and controls a switching element (T1) of the inverter.    USE - Electric motor vehicle e.g. hybrid vehicle and fuel cell vehicle.    ADVANTAGE - The vehicle controls the switching elements, so as to prevent concentration of the current generated by the electric motor if a controller for controlling the switching elements becomes unable to be supplied with electric power from a battery, thus securing electric power for controller to control the switching elements supplied other than the battery when the controller cannot receive the electric power from the battery. The controller can be supplied with electric power from the power supply circuit and can control the switching elements if the electric motor is rotated. The vehicle performs control of turning on all the three phase switching elements of the lower arms if an upper-arm switching element has short-circuit failure. The vehicle avoids concentration of current to a predetermined site in the inverter circuit or in the electric motor by turning on all the switching elements of the same-side arms as the arm of the short-circuited switching element. The vehicle provides a predetermined value that is minimum voltage needed to drive accessories, so that switch is automatically switched in accordance with reduction in the state of charge of the accessory battery. The inverter controller controls the switching elements of the voltage step-up/step-down circuit and the inverter circuit during braking of the vehicle, so that the vehicle is controlled, so as to convert the alternating-current power generated by the electric motor working as a generator into direct-current power, and reduce the voltage of the direct-current power and charge the main battery with the reduced-voltage electric power.    DESCRIPTION OF DRAWING(S) - The drawing shows a circuit block diagram of an electric power system of an electric motor vehicle.    Switching elements (T1-T6)    Electric motor vehicle (2)    Inverter (5)    Electric motor (6)    Inverter controller (9)    Transformer (12)    Primary coil (12a)    Secondary coil (12b)    Voltage regulator (15)    Power supply circuit (16)