A self-tuning regulator for induction machine vector control

In a vector controlled induction machine drive, accurate knowledge of the machine electrical parameters is required to ensure correct alignment of the stator current vector relative to the rotor flux vector, to decouple the flux and torque producing currents and to tune the current control loops. This paper presents a new method for online identification of the induction machine parameters required to tune a rotor flux oriented (RFO) vector control scheme. Accuracy of the slip frequency estimation required for RFO vector control is achieved by utilising the parameter independent flux pulse rotor time constant estimation scheme, which utilises short duration pulses injected into the flux producing current. The parameters required to tune the synchronous frame current control loops with a de-coupling circuit are estimated using a recursive estimation scheme derived from the synchronous frame voltage equations. Simulation and experimental results are presented which demonstrate the effectiveness of the on-line parameter identification and control loop tuning technique.