In a power converter, an overvoltage suppression function of low cost and
high reliability is provided. The power converter has a power conversion
circuit, when driving a motor, for converting power from a battery and
supplying it to the motor and when the motor generates power, converting
the generated power of the motor and supplying it to the battery for
storage of electricity and a drive circuit for driving the power
conversion circuit. The power conversion circuit includes a plurality of
paired switching elements, in which one of each paired switching elements
is arranged on an upper arm, and the other is arranged on a lower arm,
and each pair corresponds to each phase of the motor. The drive circuit,
when the voltage applied to the power conversion circuit is increased,
turns on all the switching elements on one arm, turns off all the
switching elements on the other arm, thereby short-circuits the output
terminals of the motor.