ELECTRIC MOTOR DRIVE DEVICE, REFRIGERATION CYCLE DEVICE, AIR CONDITIONER, WATER HEATER, AND REFRIGERATOR

An electric motor drive device (2) is provided with: a connection switching device (60) for switching the connection states of windings (71, 72, 73) of a first electric motor by switching operations of switches (61, 62, 63); an inverter (30) for applying an AC voltage to the windings; a first control device for controlling the inverter (30) and the connection switching device (60); and a second control device for controlling a second electric motor serving as a source for driving an element that influences the load of the first electric motor. The control performed by the first control device when the connection states are switched includes: a first stage in which the rms value of the AC current flowing in the windings is made closer to zero than the rms value of the AC current that was flowing in the windings before the connection states are switched is; and a second stage in which output of an AC voltage from the inverter (30) is stopped. The second control device continues the operation of the second electric motor in the time period of the first stage and second stage, and the first control device causes the connection switching device (60) to perform the switching operation of the switches (61, 62, 63) in the second stage.