| 摘要 |
PROBLEM TO BE SOLVED: To improve controllability of rotation speed control while more surely starting up a synchronous motor.SOLUTION: A rotation speed calculation unit 32 calculates rotation speed ω1 of a synchronous motor 2 by correcting a command value ω1of the rotation speed ω1 by using a correction amount obtained from the product of compensation gain and a compensation value depending on γc axis current. A voltage command calculation unit 35 generates a voltage command in a rotary coordinate system on AC voltage so that a primary magnetic flux is along the δc axis correspondingly to a primary magnetic flux command value λ. A primary magnetic flux command limitation unit 38 limits the lower limit of the primary magnetic flux command value λto a first value in a startup period until the rotation speed ω1 exceeds a reference value after starting to apply the AC voltage to the motor 2; and limits the lower limit of the primary magnetic flux command value λto a second value smaller than the first value after the startup period. |
