Speed-sensorless vector control of induction machines based on
adaptivereduced-order observer

CHEN Ling-yu^1,2, KANG Long-yun^1,2, FENG Yuan-bin^1,2

                     (1. Electric Power College , South China University of Technology, Guangzhou 510640, China; 2. Guangdong Key
                             Laboratory of Clean Energy Technology , South China University of Technology, Guangzhou 510640, China)

Abstract: Aimed at reducing the difficulty of designing stable rotor flux observer and speed adaption law for speed-sensorless induction machine drive, adaptive reduced-order observer which was implemented in estimated rotor-flux-oriented synchronous coordinates and based on error of rotor back-electromotive force vector was studied. The structures of the reduced-order observer and the speed adaption law were analyzed, and the rates of convergence of them were set reasonably, which made rotor flux observation independent of estimated speed. The implementation of speed adaption law and the stability analysis of the reduced-order observer were also simplified. Small signal analysis was utilized to provide a method for tuning stable gains of the reduced-order observer. A speed-sensorless IM vector control system was established on the digital control platform with a DSP and experiments were carried out. The results indicate that the reduced-order observer is stable in a wide range of speed, and has good steady-state, dynamic and anti-disturbance performance.
Key words: induction machine (IM); adaptive reduced-order observer; stability analysis