Control system for AC motor

摘要

A control system for an AC motor determines a slope Ktl of a tangent TL at an operating point Pa corresponding to the current motor operating state and voltage phase (theta0) on a torque characteristic curve that is plotted according to a torque equation representing an output torque characteristic with respect to the motor operating state and the voltage phase of the rectangular wave voltage. The control system further calculates a voltage phase change amount thetaff for use in feed-forward control, according to DeltaTtl/Ktl obtained by dividing a torque compensation amount DeltaTtl for feed-forward control by the slope Ktl.