INVERTER DEVICE

In a 2-shunt system, accurate sensorless vector control can be realized without increasing shunt resistors. There is disclosed an inverter device including an inverter main circuit obtained by connecting, in a three-phase bridge-like manner, three arms formed by coupling, in series with a direct-current power source, two switching elements which perform mutually opposite on/off operations, to apply three-phase pseudo alternating-current voltages of a three-phase PWM system to an electric motor; shunt resistors connected to the direct-current power source in series with at least two of the three arms of the inverter main circuit; and a controller for detecting currents flowing through the shunt resistors in a predetermined cycle to control the on/off operations of the switching elements of the inverter main circuit based on the detected currents. The controller converts, into the current value of a specific angle range, a current value detected at a time before approximately 180° corresponding to the specific angle range where the on-time of the switching elements is continuously not more than a predetermined value, and then uses the converted current value.