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Journal ArticleDOI

Improvement of Pull-Into-Step of Synchronous Motors by Nonlinear State Feedback Control

20 Jan 1994-Ieej Transactions on Industry Applications (The Institute of Electrical Engineers of Japan)-Vol. 114, Iss: 1, pp 57-63
TL;DR: In this paper, a nonlinear state feedback control of field voltage to improve the pull-in performance of the synchronous motors is proposed, which is valid in all operating area.
Abstract: The nonlinear state feedback control of field voltage to improve the pull-in performance of the synchronous motors is proposed in this paper. This nonlinear control is valid in all operating area. The machine constants are equivalently changed by the nonlinear control to improve the pull-in performance. Since the system is represented with a nonlinear system, the stability of this system is judged by Lyapunov's direct method. The optimal feedback gains of the controller are determined by using Lyapunov function. The validity and usefulness of proposed method are investigated by numerical calculations and experiments.
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Journal ArticleDOI
TL;DR: In this article, the results of many integraph solutions were made after combining the factors that influence the performance of such machines into ratios and relative factors so that the results will apply to all practical cases.
Abstract: A synchronous motor started as an induction motor must pass through an electro-mechanical transient after the field circuit is supplied with electrical excitation in order to change its action from that of an induction motor to that of a synchronous motor. The calculation of this problem has been difficult because the differential equation of motion is of a non-linear type of which no analytical solution has been made. The integraph at the Massachusetts Institute of Technology has given a new and direct method of solving equations of the type encountered in these pulling-into-step transients. In this paper are compiled the results of many integraph solutions which were made after combining the factors that influence the performance of such machines into ratios and relative factors so that the results will apply to all practical cases. From the solutions several generalizations are made which can be directly applied to determine whether or not any type of salient-pole synchronous motor will synchronize properly. These solutions take into account inertia, saliency, incompleteness of amortisseur windings, load, switching angle, and field current, and assume negligible armature resistance, negligible rotor leakage reactance, no saturation, constant load torque near synchronous speed, and negligible electrical transients. Oscillograph tests of a 160-hp. motor and a sample calculation are given.

38 citations

Journal ArticleDOI
TL;DR: The proposed Lyapunov function for stability study of the power system is constructed by the Lagrange-Charpit method and the critical reclosing times for power-system transient stability are compared.
Abstract: In this note, the transient stability of the single-machine system with the effect of the automatic voltage regulator is studied, using the direct method of Lyapunov A new Lyapunov function for stability study of the power system is constructed by the Lagrange-Charpit method The Lyapunov function is then used to estimate the critical reclosing times for power-system transient stability The critical reclosing times given by the proposed Lyapunov function are compared to those obtained by numerical integration

15 citations

Journal ArticleDOI
TL;DR: In this article, the authors used a differential analyzer to calculate quantitatively the additional load that may be synchronized if the field switch is closed at the most favorable switching angle, and obtained the curves presented in the present paper and obtained by use of the differential analyzers.
Abstract: INVESTIGATIONS of synchronous motor phenomena during transient conditions have been made, using a mechanical calculating machine called the “differential analyzer” to solve the non-linear differential equations involved. Previous investigations have been made on a preliminary calculating machine called the “product integraph.” The extent and accuracy of the solutions, however, were limited on this preliminary machine, and the work was confined principally to determining whether or not a synchronous motor would synchronize for the worst switching conditions. The curves presented in the present paper and obtained by use of the differential analyzer make it possible to calculate quantitatively the additional load that may be synchronized if the field switch is closed at the most favorable switching angle.

11 citations