Slip Gain Estimation for Indirect Field Controlled Drives Using Stator Transient Signals

Field oriented control of induction machines is a well-established technology, widely used in applications where high-bandwidth torque control of AC machines is needed. A key parameter in the implementation of the indirect field orientation (IFO) method is the slip gain, the inverse of the rotor time constant, which is used for estimation of the rotor flux angle. A method for estimating the slip gain using the transient response of the system is presented in this paper. The method uses the transient response of the stator voltage or stator flux immediately following a change in the torque command. Estimation of the slip gain using this method does not have a significant dependence on any machine or system parameter and it can be easily integrated into standard drives