| 摘要 |
PURPOSE:To make better responsibility as well as lessen the pulsation of torque by the procedure in which the instantaneous values of magnetic flux and actual current vector are always calculated or detected and the torque component current in the vertical direction to magnetic flux vector is changed according to torque command. CONSTITUTION:The output of the angular velocity detector 5 detecting the rotor angular velocity of induction motor, the magnetic flux amount command signal phi*, and torque amount command signal tau* are put in the current arithmetic circuit 8 to calculate the direction of primary winding current vector of induction motor on the basis of the phase commutation of converter, and the primary winding current instantaneous value from the current instantaneous value command arithmetic circuit 9 is put in the magnetic flux arithmetic circuit 15 to calculate magnetic flux instantaneous value for determining the phase current peak value and phase commvtation timing of induction motor. Thus, the pulsation to torque due to the stepwise change of the conventional current vector can be suppressed particularly at low driving frequency, and slip frequency is automatically determined according to load and thus stable operation can be assured for all cases including normal and reverse rotations. |
