CONTROL OF CURRENT-FED INDUCTION MOTORS POWERED BY CURRENT SOURCE

Novel solution of the induction motor speed-flux tracking control problem has been developed and experimentally tested. Direct rotor flux field oriented controller is designed for current-fed induction motor model and uses full order sliding mode flux observer. Controller guarantees local asymptotic speed-flux tracking and asymptotic direct field-orientation under condition of unknown constant load torque. Asymptotic decoupling of speed and flux subsystems is achieved. Flux subsystem is invariant with respect to limited rotor resistance variations due to special structure of the sliding mode observer. The efficiency of the proposed solution confirmed by the results of experimental studies and simulation, which demonstrated strong robustness properties with respect to rotor resistance variations in all motor op-erating conditions including near by zero speeds.