An adaptive rotor flux observer for direct field oriented induction motor drives

✍ Scribed by A. Damiano; G. Gatto; I. Marongiu

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 311 KB
• Volume: 14
• Category: Article
• ISSN: 0890-6327
• DOI: 10.1002/(sici)1099-1115(200003/05)14:2/3<275::aid-acs576>3.0.co;2-e

✦ Synopsis

At the present time the direct "eld oriented (DFO) control is the widely used control technique in high-performance induction motor (IM) drive. It requires the implementation of a state vector observer for the detection of rotor #ux vector. The IM drive performance is strictly connected to that of the rotor #ux observer. The motor parameter variations cause the observer mismatching and hence, the IM drive performance degradation. In the present paper an adaptive observer is proposed which allows the on-line rotor time-constant tuning. The identi"cation of the rotor time constant is performed by an MRAS approach. The adaptive observer is synthesized using the Lyapunov stability theory. To improve the speed convergence of the identi"er and the selectivity characteristic of the proposed adaptive observer, a timevarying gain has been introduced. The stability of the overall system has been veri"ed using the Lyapunov stability theory. The simulation results evidence the good performance of the proposed observer and of the overall DFO controlled drive. In particular, the interactive e!ects between observer and identi"er gains are evidenced and, thus, used for the selection of the identi"er time-varying gain.