AC ELECTRIC MOTOR CONTROLLING APPARATUS AND CONTROLLING METHOD

A voltage command generation unit (240) generates a voltage command value (Vd#, Vq#), based on a current deviation (Id, Iq) relative to a current command value (Idcom, Iqcom). A dq-axis voltage filter (300) generates a voltage command value (Vdf, Vqf) subjected to a filtering process for smoothing a change of the voltage command value (Vd#, Vq#) in a time axis direction. Then, the voltage command value (Vdf, Vqf) subjected to the filter processing is subjected to a voltage amplitude correcting process and a two-phase to three-phase coordinate converting process, so that a phase voltage command for an AC motor M1 is generated. Thus, it is possible to prevent both an amplitude and a phase of the voltage command for the AC motor M1 from being changed rapidly even at a time of control mode switchover.