| 摘要 |
The purpose of this invention is to provide secondary resistance low temperature compensation in vector speed control at values that are close to the actual secondary time constant even at startup of the motor when the secondary time constant calculation operation is not carried out. The invention consists of vector speed control devices 1 to 5 of the induction motor IM, with secondary resistance low temperature compensation of the electric motor being carried out by installing a secondary time constant operator (6) which detects the secondary time constant of the electric motor; a comparator/register (7) which holds and outputs low temperature data t2L by comparing and holding the lower temperature one of register data and the output t<6> of the aforementioned operator (6); and a damping unit (8) which, during operation, carries out replacement of sequential data with the output t<6> of the operator (6), and, during shutdown, outputs values t<6>* to a slip angular frequency operator (5) of the vector control circuit, which values slowly change from the value t<6> at the stop of operation to the value t2L. In another embodiment the value t<6>* can switch from the t<6> value at the stop of operation to the value t2L a predetermined time after the stop. The value t2L may instead be determined as the first calculated t<6> value on initial operation after a stop for a predetermined time. <IMAGE> |
