Study of Reduced-order Models of Squirrel-cage Induction Motors

Abstract

This article examines several reduced-order models of squirrel-cage induction motors. The full-order model and its reduced-order models are used to calculate motor speed behavior during symmetrical voltage sags. The stability predicted by several reduced-order models of induction motors during symmetrical voltage sags with different depths and durations is also explored. Moreover, simulations of 36 motors of different power ratings are performed, and results are compared with simulations made with the classical fifth-order single-cage model and its corresponding reduced-order models. The main conclusion is that for speed stability evaluation purposes, even the reduced first-order double-cage model gives better results than the fifth-order single-cage model, which neglects the deep-bar effect.

Keywords:

• reduced-order induction motor models
• single- and double-cage models
• critical clearing time
• symmetrical voltage sags

Acknowledgments

The authors acknowledge the financial support of the Comisión Interministerial de Ciencia y Tecnología (CICYT; project ENE2009-10274). The authors would like to thank Amalia Barrera and Francesc Quintana from Asea Brown Boveri, S. A., Fábrica de Motores, for providing the experimental data of the motors in Figure 2.