A sensorless induction motor flux observer with inaccurate speed input based on an alternative state-space model

Trey Mock, Randi Bimeal, Stephen Ling, Mihai Comanescu

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The paper discusses the problem of flux estimation for the induction motor (IM) drive and presents a sensorless observer. The intention is to estimate the IM fluxes in the stationary reference frame in order to obtain both the magnitude and the angle of the rotor flux. The flux magnitude is typically used for d axis feedback; the flux angle is needed for field orientation. The paper presents an alternative state-space model of the IM. Based on this, a Lyapunov-type nonlinear state observer with continuous feedback is designed. The paper first assumes that the speed is known and develops a sensored observer; then, this is transformed into a sensorless observer by feeding it with a speed estimate (assumed inaccurate). This method eliminates the speed measurement. The paper shows that, despite the improper speed input, the design yields a partially accurate estimate of the state vector that is sufficient for obtaining the magnitude and angle of the flux. Previous observers developed under the same conditions based on the traditional IM model were only capable of estimating the angle of the flux (but not the magnitude). The novelty is that this method also yields an accurate flux magnitude. It is shown that the equilibrium point of the observer is influenced by the design gains; with high enough gain, the observer converges. The theoretical developments are supported by simulations.

Original languageEnglish (US)
Title of host publication7th IET International Conference on Power Electronics, Machines and Drives, PEMD 2014
PublisherInstitution of Engineering and Technology
Edition628 CP
ISBN (Print)9781849198158
DOIs
Publication statusPublished - Jan 1 2014
Event7th IET International Conference on Power Electronics, Machines and Drives, PEMD 2014 - Manchester, United Kingdom
Duration: Apr 8 2014Apr 10 2014

Publication series

NameIET Conference Publications
Number628 CP
Volume2014

Other

Other7th IET International Conference on Power Electronics, Machines and Drives, PEMD 2014
CountryUnited Kingdom
CityManchester
Period4/8/144/10/14

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All Science Journal Classification (ASJC) codes

  • Electrical and Electronic Engineering

Cite this

Mock, T., Bimeal, R., Ling, S., & Comanescu, M. (2014). A sensorless induction motor flux observer with inaccurate speed input based on an alternative state-space model. In 7th IET International Conference on Power Electronics, Machines and Drives, PEMD 2014 (628 CP ed.). (IET Conference Publications; Vol. 2014, No. 628 CP). Institution of Engineering and Technology. https://doi.org/10.1049/cp.2014.0294