| 摘要 |
PURPOSE:To control vectors with high precision without being affected by a parameter extending over overall speed regions by changing over slip frequency type vector control and flux detection type vector control in response to speed. CONSTITUTION:With flux detection type vector control, the absolute value i1 of a primary synthetic current command and a phase angle theta1 are output from a polar coordinate transformation apparatus 39 by using a flux computing element 26 and a vector analyzer 27. With slip frequency type vector control, a slip frequency command omegaS is produced by a slip-frequency computing element 35, and a primary frequency command omega1 is manufactured by adding the command omegaS and rotational frequency omegaR. In a changer 40, a contact A is selected or a contact B is selected in response to rotational frequency omegaR acquired by a speed detector 4. |
