Patent ID: 8605461

Claim:
A phase current detection device for detecting a phase current of an output alternating current in an inverter circuit which converts a direct current into an alternating current by changing respective switching states of a plurality of switching elements, the device comprising: a shunt resistor configured to output a voltage pulse of a voltage corresponding to the phase current; a control section configured to change each of the switching states of the switching elements so that inverter control for controlling a current or a voltage generated by the output alternating current is repeated in units of an inverter control period having a predetermined length; and a detection section configured to detect the phase current based on the voltage pulse, wherein the control section controls the switching states of the switching elements so that a phase current detection period, in which the phase current is detected, is provided between the predetermined inverter control periods, and a voltage pulse is output from the shunt resistor in the phase current detection period, the voltage pulse in the phase current detection period having a larger width than a width of the voltage pulse in the inverter control period, and the detection section detects the phase current using a voltage pulse in the phase current detection period.