Electric motor drive device

An electric motor drive device includes: a wire connection switching unit; an inverter; a control device controlling the wire connection switching unit and the inverter; and an overcurrent protection circuit preventing current exceeding a predetermined value from continuously flowing through the electric motor. The overcurrent protection circuit includes: determination circuits each correlated one-to-one with any one of possible wire connection states of a stator winding and determining whether current flowing through the inverter is abnormal; a combining circuit combining determination results; and an invalidation circuit invalidating a determination process by one or more of the determination circuits, and causing the combining circuit to output a determination result by the determination circuit correlated with a selected wire connection state of the stator winding. When the determination result output from the combining circuit indicates an abnormal value of the current flowing through the inverter, the control device stops the inverter.