| 摘要 |
<P>PROBLEM TO BE SOLVED: To enable the fault diagnosis of a current sensor detecting current flowing in an AC motor to be performed with high reliability without causing trouble in drive control of the AC motor in a motor drive control system. <P>SOLUTION: A phase current operation unit 320 estimates phase current of an AC motor 200 on the basis of: a detection value of bus current Idc detected by a current sensor 180; and a switching pattern indicating a combination of on/off for switching elements Q3-Q8 of an inverter 140. A phase current comparison unit 330 diagnoses a fault of a current sensor 240 on the basis of a comparison result between the estimation value of phase current by the phase current operation unit 320 and the detection value of phase current by the current sensor 240. A control unit 340 has an execution period of the fault diagnosis for the current sensor 240 when background noise caused by drive of the AC motor 200 occurs, and the frequency of a carrier wave used for a control command operation unit 310 is temporarily lowered during the execution period of the fault diagnosis. <P>COPYRIGHT: (C)2013,JPO&INPIT |
