To provide a motor controller which reduces a ripple current of a DC bus when three or more AC motors are driven severally with inverters, using a common DC power source.

This motor controller, which drives first to third AC motors 10, 20 and 30 by severally generating PWM voltages, by first to third inverters 11, 21 and 31 connected via DC common buses from a common DC power source 1, using the carriers for generation of PWM waves of the same frequency, detects the power running state or the regenerative state of the first to third AC motors 10, 20 and 30, and decides the phases ph1, ph2 and ph3 of carriers for generation of PWM waves of the first to third inverters 11 to 12, 21 to 22 and 31 to 32, according to the power running state or the regenerative state of the first to third AC motors 10, 20 and 30.

COPYRIGHT: (C)2005,JPO&NCIPI