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Describing function

About: Describing function is a research topic. Over the lifetime, 1742 publications have been published within this topic receiving 26702 citations.


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Journal ArticleDOI
01 Jul 1970
TL;DR: In this paper, the authors investigated the common features of continuous-system design methods for stable thyristor-bridge control systems, and the implications of applying these techniques to a discrete control system are discussed.
Abstract: Part 1 of the paper developed discrete models of thyristor-bridge control systems, and introduced some simple design roles for ensuring stability. The present paper investigates the common features of continuous-system design methods for stable thyristor-bridge control systems, and the implications of applying these techniques to a discrete control system are discussed. This is followed by a detailed discussion of the existing describing-function method. Results for describing functions obtained by using crosscorrelation techniques are given. The critical conditions for 1st- and 2nd-order systems are used to show that the Nyquist conditions for stability must take into account critical points other than the point (− 1, 0). A derivation of the equation for the general translation of the critical point is given using discrete-system methods, and a discussion on the translation for low- and high-bandwidth systems follows. An example shows the use of the equation in synthetising the minimum sampling frequency for a given continuous system. An example of a halfsection filter is investigated using discrete-system and root-locus techniques, and the results are used to show that unstable systems exhibit some interesting random characteristics.

9 citations

Journal ArticleDOI
James Taylor1
TL;DR: Based on the software presented here, the use of SIDF-based nonlinear control system analysis and design methods is substantially easier to carry out.

9 citations

Proceedings ArticleDOI
10 Jun 2009
TL;DR: A tool for generating a self-excited oscillations for an inertia wheel pendulum by means of a variable structure controller by using Describing Function (DF) method for finding the explicit expressions of the two-relays controller gain parameters in terms of the desired frequency and amplitude.
Abstract: A tool for generating a self-excited oscillations for an inertia wheel pendulum by means of a variable structure controller is proposed. The original system is transformed into the normal form for exact linearization. The design procedure, based on Describing Function (DF) method, allows for finding the explicit expressions of the two-relays controller gain parameters in terms of the desired frequency and amplitude. Necessary condition for orbital asymptotic stability of the output of the exactly linearized system is derived. Performance issues of the system with self-excited oscillations are validated with experiments.

9 citations

Proceedings ArticleDOI
05 Sep 2012
TL;DR: The EDF method is used to express non-linear terms of switching waveforms as linear descriptors to develop a linear model of the converter to solve the steady-state analysis of series resonant converter.
Abstract: This paper presents the steady-state analysis of series resonant converter (SRC) using the extended describing function (EDF) method. The EDF method is used to express non-linear terms of switching waveforms as linear descriptors to develop a linear model of the converter. The converter under consideration consists of a half-bridge inverter and a full-wave rectifier. The steady-state analysis in the frequency-domain is presented. The characteristics such as input-to-output-voltage transfer function and input impedance are obtained by first harmonic approximation of the converter state variables. Experimental results are given for a laboratory prototype of the SRC operating at 24 VDC input, 10 VDC output, output power of 15 W, and at a switching frequency of 110 kHz to verify the theoretical analysis.

9 citations

Book ChapterDOI
01 Jan 2012
TL;DR: In this paper, an approach for detection, localization, characterization, and parametric identification of nonlinear elements by using incomplete FRF data is proposed, which is made possible to identify the restoring force of more than one type of non-linearity which may coexist at the same location.
Abstract: Most engineering structures include nonlinearity to some degree. Depending on the dynamic conditions and level of external forcing, sometimes a linear structure assumption may be justified. However, design requirements of sophisticated structures such as satellites require even the smallest nonlinear behavior to be considered for better performance. Therefore, it is very important to successfully detect, localize and parametrically identify nonlinearity in such cases. In engineering applications, the location of nonlinearity and its type may not be always known in advance. Furthermore, in most of the cases, test data will be incomplete. These handicaps make most of the methods given in the literature difficult to apply to engineering structures. The aim of this study is to improve a previously developed method considering these practical limitations. The approach proposed can be used for detection, localization, characterization and parametric identification of nonlinear elements by using incomplete FRF data. In order to reduce the effort and avoid the limitations in using footprint graphs for identification of nonlinearity, describing function inversion is used. Thus, it is made possible to identify the restoring force of more than one type of nonlinearity which may co-exist at the same location. The verification of the method is demonstrated with case studies.

9 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202312
202230
202142
202057
201953
201847