| 摘要 |
PURPOSE:To continue current detection without hindrance even if a current sensor for one phase has failed, by providing a current sensor malfunction detecting means, a malfunction phase specifying means, a malfunction phase current computing means, and a detected current value switching means. CONSTITUTION:A primary part is constituted of a control part 1, an electric power conversion device 2, an induction motor 3, current sensor 4, a current sensor malfunction detecting means 10, a malfunction phase specifying means 20, a malfunction phase current computing means 30, and a detected current value switching means 40. When the current sensor malfunction detecting means 10 has no output, the value of the current sensor 4 of each phase is considered to be a detected current value as it is. If the current sensor malfunction detecting means 10 has an output, the malfunction phase specifying means 20 specifies a malfunction phase, the malfunction phase current computing means 30 computes the current value of the malfunction phase, and the detected current value switching means 40 switches the abnormal current value to the computed normal one. Accordingly, it is possible to operate normally unless current sensor for two phases or more fail simultaneously. |
