Fuzzy logic based on-line MRAC tuning of slip gain for an indirect vector-controlled induction motor drive

Slip gain tuning of indirect vector controlled induction motor drive has been a subject of intense research interest in recent years. The paper proposes the fuzzy logic based online tuning of slip gain using the standard model reference adaptive control (MRAC) technique. MRAC methods based on reactive power and D-axis voltage are combined together with a weighting factor that is generated by a fuzzy controller. The weighting factor ensures the dominant use of the reactive power method in the low speed-high torque region whereas the D-axis voltage method is dominant in the high speed-low torque region. A second fuzzy controller tunes the slip gain based on the combined detuning error and its slope so as to ensure fast convergence at any operating point on the torque-speed plane. A complete vector controlled induction motor drive with the proposed tuning controller is been simulated and the performance of the drive is extensively investigated. The control software is implemented in assembly language in a TMS320C25 digital signal processor which is interfaced with an experimental laboratory drive system. The test results correlate with theoretical and simulation performances, and demonstrate the superior performance of the proposed tuning system