| 摘要 |
<P>PROBLEM TO BE SOLVED: To control motor current appropriately when the r.p.m. of a motor changes suddenly in AC motor control by a modulation system where the basic wave component of applied voltage of the motor is larger as compared with sine wave PWM control system. <P>SOLUTION: A rectangular wave voltage having the output voltage VH of a converter 12 as an amplitude is applied to an AC motor M1 by a rectangular wave control block 400. Torque control of the AC motor M1 is basically performed by varying the phase ϕv of the rectangular wave voltage depending on torque deviation ΔTq. When the r. p. m. Nmt of a motor changes suddenly, a VH command value correcting section 320 sets a voltage command value VH# of the output voltage VH from the converter 12 is set depending on the variation ratio of r. p. m. of the motor. Consequently, controllability of motor current can be enhanced by varying applied voltage of the motor in correspondence with sudden variation in r. p. m. of the motor without waiting torque feedback control where control response is not so high. <P>COPYRIGHT: (C)2007,JPO&INPIT |
