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About 10,000 papers for “Phase margin”

Model Reduction for Keeping Gain Margin and Phase Margin Unchanged

Jium-Ming Lin, Kwang-Wei Han · IEEE Transactions on Industry Applications · 1986

The effects of model reduction on system characteristics, such as gain margin, phase margin, and bandwidth are investigated. A practical method is proposed so that the reduced models can approximate the frequency response of the original transfer function not only at S = 0 and S = ∞ but also at some specific points on the frequency response curve of the original system; thus the gain margin and/or phase margin can be kept unchanged. Examples are given, and comparisons with the methods given in current literature are made.

Cited by 8

Gain-Phase Margin of MIMO Control Systems

Radik Srazhidinov, Jiajin Liang, Li Qiu · IFAC-PapersOnLine · 2023

This paper defines the gain-phase margin of multivariable control systems. This stability margin is studied using the concept of the Davis-Wielandt shell of complex matrices. The lower bound of the gain-phase margin is obtained using the semidefinite relaxation of a parametrized quadratically constrained quadratic program. Numerical examples are given to illustrate the effectiveness of the proposed algorithm.

Cited by 1Open access

Bode's maximum available feedback and phase margin

CentAUR (University of Reading) · 2004

'Maximum Available Feedback' is Bode's term for the highest possible loop gain over a given bandwidth, with specified stability margins, in a single loop feedback system. His work using asymptotic analysis allowed Bode to develop a methodology for achieving this. However, the actual system performance differs from that specified, due to the use of asymptotic approximations, and the author[2] has described how, for instance, the actual phase margin is often much lower than required when the bandwidth is high, and proposed novel modifications to the asymptotes to address the issue. This paper gives some new analysis of such systems, showing that the method also contravenes Bode's definition of phase margin, and shows how the author's modifications can be used for different amounts of bandwidth.

Cited by 0

Bode's maximum available feedback and phase margin

Richard Mitchell · 2004

'Maximum Available Feedback' is Bode's term for the highest possible loop gain over a given bandwidth, with specified stability margins, in a single loop feedback system. His work using asymptotic analysis allowed Bode to develop a methodology for achieving this. However, the actual system performance differs from that specified, due to the use of asymptotic approximations, and the author[2] has described how, for instance, the actual phase margin is often much lower than required when the bandwidth is high, and proposed novel modifications to the asymptotes to address the issue. This paper gives some new analysis of such systems, showing that the method also contravenes Bode's definition of phase margin, and shows how the author's modifications can be used for different amounts of bandwidth.

Cited by 1

The geometry of the multivariable phase margin

J.R. Bar-on, Edmond Jonckheere · IEEE Transactions on Automatic Control · 1992

A collection of multiplicative perturbations with a given structure can be viewed as a nontrivial n-dimensional manifold. This manifold can be divided into regions of stability and instability where the unperturbed identity matrix is a point on the manifold. The stability margin for a collection of such structured perturbations can be defined as the smallest distance on the manifold from the identity matrix to the region of instability. The class of unitary perturbations which has been shown to define the multivariable phase margin is examined. Specifically, it is seen that the margin is the smallest arc length on the three-sphere S/sup 3/ between the north pole and the region of instability.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Cited by 8

Robustness of suboptimal control: Gain and phase margin

M.E. Sezer, D.D. Šiljak · IEEE Transactions on Automatic Control · 1981

The purpose of this paper is to introduce the gain and phase margin as measures of robustness of suboptimal linear-quadratic regulators. It will be shown that the suboptimal control retains the infinite gain margin of the corresponding optimal system, but that the phase margin and gain reduction tolerance depend on the degree of suboptimality of the nominal optimal control law. This establishes the degree of suboptimality as an index of both the system performance regarding the optimality criterion and the robustness to plant parameter uncertainties and distortions of the optimal control law. It will also be shown that the suboptimal closed-loop systems remain stable despite insertion of memoryless nonlinear gains inside individual feedback loops, thus raising further the confidence in suboptimal designs of linear-quadratic regulators.

Cited by 47

PID Tuning for Dominant Poles and Phase Margin

Wei Tang, Qing‐Guo Wang, Zhen Ye et al. · 2006

A simple PID tuning method for dominant pole placement and phase margin specification is proposed in this paper. Time domain specifications as settling time and percentage overshoot are represented by a pair of dominant poles, which is combined with phase margin specification to achieve closed-loop stability and robustness. A graphical method is developed to determine PID settings to meet these specifications simultaneously. An example is given for illustration

Cited by 5

Linear Voltage Regulator Stability Analysis through Phase Margin

Ibrahim, Muhammad Aidil, Mohd Hairi Mohd Zaman, Ibrahim, Ahmad Asrul et al. · Zenodo (CERN European Organization for Nuclear Research) · 2018

Most linear voltage regulators require an output capacitor with specific value of internal parasitic element called equivalent series resistance (ESR). This ESR range must be characterized to ensure the stability of the voltage regulator is guaranteed. Instability of the linear voltage regulator such as indicated by excessive overshoot and undershoot of output voltage give negative effect on the electronic devices. Therefore, this study aims to investigate the range of ESR through phase margin measurement. LTspice simulation software was used to simulate a voltage regulator circuit, that contains an adjustable ESR as well as load. This software was also used to assist in the process of detailing the value of ESR and determining the output voltage stability through phase margin measurements. To conclude, this research able to identify the ESR range that need to be used to produce stable output voltage.

Cited by 0Open access

Gain/phase margin design with first order controllers

R.N. Tantaris, L.H. Keel, S.P. Bhattacharyya · 2004

The problem of determining all first order controllers (C(s) = x/sub 1/s+x/sub 2//s+x/sub 3/) that stabilize a fixed plant Po(s) has been recently solved in [R.N. Tantaris et.al., Proceeding of The 10th Mediterranean Conference on Control and Automation, Lisbon, Portugal, July 9-12, 2002]. In the present paper we extend this solution to the problems of simultaneously stabilizing the continuum of plants a) KPo(s) with K lying in a prescribed interval and b) e/sup j/spl theta// Po(s) with /spl theta/ lying in a known interval. Our solution answers the question of when prescribed gain and phase margins can be attained, for the given plant, with first order controllers and when possible, gives the complete set attaining specifications. It is shown how such sets can then be used to obtain prescribed target closed loop transfer functions within specified tolerances. Examples are given for illustrations.

Cited by 9