In a control apparatus, a fundamental voltage generator generates, based on a target rotational speed, a fundamental voltage command for a fundamental voltage. A property storage stores a natural vibration property of a rotor when the rotor is rotating as a rotating vibration property. A rotating state detector detects a rotating position and a rotational speed of the rotor as a rotating state of the rotor. A harmonic voltage generator generates, based on the rotating state of the rotor and the rotating vibration property, a harmonic voltage command to be superimposed on the fundamental voltage command generated by the fundamental voltage generator.