Patent ID: 7005819

Claim:
An apparatus for controlling a traction motor equipped in a vehicle, the traction motor being composed of alternating-current motor generating a driving torque necessary for running the vehicle, comprising: a detector detecting a rotational speed of the traction motor and a current supplied to the traction motor; a torque-command calculator calculating a torque command value based on information including acceleration information obtained in the vehicle; a current-command calculator unit calculating a current command value based on the torque command value and the detected rotational speed of the traction motor; a voltage-command calculator calculating a voltage command value based on a difference between the detected current and the current command value, the voltage command value allowing the difference to converge to zero and being applied to the traction motor; a memorizing unit previously memorizing information indicative of a relationship between an electric amount relating to driven conditions of the traction motor and a preferable voltage range to be applied to the traction motor; a regulator regulating the calculated voltage command value within the preferable voltage range, using the information indicative of the relationship; and an inverter producing a drive voltage corresponding to the regulated voltage command value and applying the produced drive voltage to the traction motor.