| 摘要 |
PROBLEM TO BE SOLVED: To accurately detect the abnormality of an inverter in a motor driving system which has an AC motor capable of switching its control mode.SOLUTION: An offset F/B processor 300 corrects each phase voltage command, based on an offset correction computed from each phase motor current. A control mode determiner 260 performs switching between a PWM control mode and a rectangular-wave voltage control mode, according to the operating conditions of an AC motor M1. An abnormality detector 400 determines whether a state that an offset F/B integration term computed by PI calculation with the offset F/B processor 300 exceeding threshold has continued for a specified time. When it is determined that the state of the interval over the threshold has continued over a specified interval, the detector detects that an inverter 14 is abnormal. The abnormality detector 400 corrects the threshold in the direction of increase, when it is determined that the changeover of the control mode is required, as well as when the change in torque or the change in revolution at a specified value or over is detected in the AC motor M1. |
