DETECTION METHOD AND DEVICE FOR FAILURE IN THREE-PHASE MOTOR

PROBLEM TO BE SOLVED: To provide a detection method for failure in a three-phase motor capable of detecting failure in a current sensor with high precision in a control system where a following delay in current occurs. SOLUTION: If the current sensors 7-1, 7-2 is determined as being failed, calculation (a current PI control part 2) of a d-axis current command value and a q-axis current command value, and a d-axis voltage command value and a q-axis voltage command value based on the d-axis current command value and the q-axis current command value is stopped to set the d-axis voltage command value and the q-axis voltage command value at a prescribed fixed value respectively, and the d-axis current command value and the q-axis current command value, and the d-axis voltage command value and the q-axis voltage command value are compared with each other. If at least any one of a difference between the d-axis current command value and the q-axis current command value, and a difference between the d-axis voltage command value and the q-axis voltage command value is above a prescribed value, the current sensor is determined as being failed. COPYRIGHT: (C)2005,JPO&NCIPI