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| Publication: Cao, L. and Schwartz, H.M., "Oscillation, Instability and Control of Stepper Motors" |
| Abstract: A novel approach to analyze instability in permanent-magnet stepper motors is presented. It is shown that there are two kinds of unstable phenomena in this kind of motor: mid-frequency oscillation and high frequency instability. Nonlinear bifurcation theory is used to illustrate the relationship between local instability and mid-frequency oscillatory motion. A novel analysis is presented to analyze the loss of synchronism phenomenon, which is identified as high frequency instability. The concept of separatrices and attractors in phase space are used to derive a quantity to evaluate the high frequency instability. A generalized approach to analyze the stabilization problem based on feedback theory is given. It is shown that the mid-frequency stability can be improved by state feedback. |