Patent ID: 8040086

Claim:
A current detector unit comprising: a current detecting portion detecting a current flowing between a three-phase inverter and a direct-current power supply as a detection current; a three-phase current detecting portion for detecting a three-phase current of the inverter based on the detection current; and a judging portion judging, based on the detection current, whether or not a target time point belongs to a period during which the three-phase current can be detected; wherein, if the judging portion judges that the target time point belongs to the period, the three-phase current detecting portion detects the three-phase current; wherein the judging portion judges whether or not the target time point belongs to the period by comparing a magnitude of the detection current, a first-order difference value of the detection current, or a second-order difference value of the detection current with a predetermined determination threshold value; and wherein the determination threshold value is set to a value that is equal to or smaller than one-half of a maximum value of the detection current.