| 摘要 |
PROBLEM TO BE SOLVED: To shorten winding changing time without causing a nonconforming state in which current control is not performed properly after winding changeover, because of the welding of a contact of a winding change-over magnet and remaining induced voltage inside an induction motor. SOLUTION: A current command change-over signal is outputted according to a winding change-over command. An exciting current command change-over switch 21 and a torque current command change-over switch 22 set respective current commands to zero, in accordance with the current command change-over signal. An exciting current id and a torque current iq are feedback-controlled and id=0 and iq=0 are satisfied. A winding change-over controller 12 outputs a voltage interrupt on signal, when an exciting current detected value and a torque current detected value become zero. A voltage command circuit-breaker 13 interrupts a current flow to an induction motor, on the basis of a voltage interrupt command. The change-over controller 12 outputs a voltage interrupt off signal, after outputting the voltage interrupt command. The circuit-breaker 13 begins to cause a current to flow into the induction motor, on the basis of the voltage interrupt command. |
