scispace - formally typeset
Search or ask a question
Topic

Describing function

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


Papers
More filters
Proceedings ArticleDOI
01 Sep 2018
TL;DR: A high frequency accurate small signal model for IQCOT control has been derived using describing function method and an auto-tuning method for Q-value control is proposed in this paper.
Abstract: These days, constant on-time current mode (COTCM) control schemes are very popular in the multiphase voltage regulator (VR) controllers because of its higher light load efficiency and better small signal characteristics. The issue of these ripple based COTCM control in multiphase operation is that when the inductor current ripple becomes very small at certain duty cycles due to ‘ripple cancellation effect’, control becomes very noise sensitive. Recently, a novel non-ripple based ‘Inverse Charge Constant On-Time (IQCOT)’ control has been proposed which can operate seamlessly at ripple cancellation point in multiphase operation. This new control improves the transient response in single and multiphase operations too. However, a high frequency small signal model for this new IQCOT control is required for its high bandwidth control loop design. In this paper, a high frequency accurate small signal model for IQCOT control has been derived using describing function method. Form the derived model it is found that the quality factor (Q) of one double pole set varies with duty cycle change which makes the high bandwidth design very challenging for a wide duty cycle range. To overcome this challenge, an auto-tuning method for Q-value control is also proposed in this paper. The derived high frequency model and auto-tuning method are also verified by small signal bode plot simulation and test results.

5 citations

Proceedings ArticleDOI
TL;DR: In this paper, the authors investigated the global dynamic behavior of weakly connected cellular networks of oscillators and derived an analytic expression of the phase deviation equation via the joint application of the describing function technique and of Malkin's Theorem.
Abstract: Many studies in neuroscience have shown that nonlinear dynamic networks represent a bio-inspired models for information and image processing. Recent studies on the thalamo-cortical system have shown that weakly connected oscillatory networks have the capability of modelling the architecture of a neurocomputer. In particular they have associative properties and can be exploited for dynamic pattern recognition. In this manuscript the global dynamic behavior of weakly connected cellular networks of oscillators are investigated. It is assumed that each cell admits of a Lur'e description. In case of weak coupling the main dynamic features of the network are revealed by the phase deviation equation (i.e. the equation that describes the phase deviation due to the weak coupling). Firstly a very accurate analytic expression of the phase deviation equation is derived via the joint application of the describing function technique and of Malkin's Theorem. Then it is shown that the total number of periodic limit cycles with their stability properties can be estimated through the analysis of the phase deviation equation.

5 citations

Proceedings ArticleDOI
27 Jun 2007
TL;DR: The procedure is illustrated on determination of describing function, and corresponding error estimation, of nonlinear structure consisting of fuzzy element and typical nonlinear element.
Abstract: Engineering procedure for approximate analytical determination of describing function of nonlinear systems with odd static characteristics is presented in the paper. Generalized mathematical expressions for determining such describing function with error estimation are given. The procedure is illustrated on determination of describing function, and corresponding error estimation, of nonlinear structure consisting of fuzzy element and typical nonlinear element.

5 citations

Journal ArticleDOI
TL;DR: For the automatic tuning of PID controllers, a new identification method is proposed to estimate the frequency responses of the process from the activated process input and output that can extract many more frequency responses as well as guarantee better accuracy compared with the previous describing function analysis algorithm.
Abstract: For the automatic tuning of PID controllers, a new identification method is proposed to estimate the frequency responses of the process from the activated process input and output It can extract many more frequency responses as well as guarantee better accuracy compared with the previous describing function analysis algorithm Also, the proposed method can be applied to the case that the initial part of the activated process input and output is periodic (cyclic-steady-state), whereas the previous method using the modified Fourier transform cannot incorporate the case

5 citations

Journal ArticleDOI
TL;DR: In this article, a multivariable non-linearity with given multiple input describing functions is synthesized, and examples are given to illustrate the procedure and to show how it may be used in the design of feedback systems.
Abstract: Theoretical results are derived showing how a multivariable non-linearity with given multiple input describing functions may be synthesized. Examples are given to illustrate the procedure and to show how it may be used in the design of feedback systems.

5 citations


Network Information
Related Topics (5)
Control theory
299.6K papers, 3.1M citations
90% related
Linear system
59.5K papers, 1.4M citations
88% related
Control system
129K papers, 1.5M citations
86% related
Robustness (computer science)
94.7K papers, 1.6M citations
83% related
Electric power system
133K papers, 1.7M citations
80% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202312
202230
202142
202057
201953
201847