Slip-gain estimation in field-orientation-controlled induction machines using the system transient response

Field-oriented control of induction machines is well established and widely used in applications where high-bandwidth torque control of ac machines is needed. A key parameter in the implementation of indirect field orientation is the slip gain (inverse of the rotor time constant), which is used to estimate the rotor flux angle. A new method for estimating the slip gain is presented in this paper. The method uses the transient response of the stator voltages following a change torque for these purposes. The method is independent of any machine or system parameter and can be easily integrated into standard drives and used in many industrial applications.