scholarly journals Influence of the switching frequency of the switch and the amplitude of the reference voltage of a pulsed voltage regulator of the lowering type on its stability

2021 ◽  
Vol 24 (2) ◽  
pp. 103-108
Author(s):  
Danil L. Myasnikov ◽  
Roman S. Demidov ◽  
Yulia V. Sokolova
Keyword(s):  
Transfer Function ◽  
Phase Stability ◽  
Loop System ◽  
Reference Voltage ◽  
Voltage Regulator ◽  
Switching Frequency ◽  
Sawtooth Voltage ◽  
Nyquist Criterion ◽  
The Stability ◽  
Pulsed Voltage

On the basis of classical stability criteria, using the expressions of the transfer function, according to the block diagram, the stability of the impulse controller with feedback is estimated. The influence of the switching frequency of the switch and the amplitude of the reference voltage on the stability of a pulsed voltage regulator of a lowering type with deterministic parameters of the system is analyzed. In accordance with the Nyquist criterion for the transfer function of an open-loop system, both stability and phase stability margins for a closed-loop system can be estimated. When simulating the operation of the device, the phase stability margin was obtained, according to the Nyquist criterion, which is с = Н = 7. An increase in the sawtooth voltage is not a desirable phenomenon, which, although it increases the margin of stability, however, reduces stability. Moreover, the dependence of the ripple, affecting the stability of operation, on the amplitude of the sawtooth voltage is not a predictable value and takes on a random value.

A New Approach to the Stability Analysis of Boost Power-Factor-Correction Circuits

2003 ◽  
Vol 9 (7) ◽  
pp. 749-773 ◽  
Author(s):  
Sudip K. Mazumder ◽  
Ali H. Nayfeh
Keyword(s):  
Power Factor ◽  
Closed Loop ◽  
Power Factor Correction ◽  
Loop System ◽  
Switching Frequency ◽  
Sliding Surface ◽  
Closed Loop System ◽  
Line Voltage ◽  
Torus Breakdown ◽  
The Stability

We analyze the stability of a boost power-factor-correction (PFC) circuit using a hybrid model. We consider two multi-loop controllers to control the power stage. For each closed-loop system, we treat two separate cases: one for which the switching frequency is approaching infinity and the other for which it is finite but large. Unlike all previous analyses, the analysis in this paper investigates the stability of the converter in the saturated and unsaturated regions of operation. Using concepts of discontinuous systems, we show that the global existence of a smooth hypersurface for the boost PFC circuit is not possible. Subsequently, we develop conditions for the local existence of each of the closed-loop systems using a Lyapunov function. In other words, we derive the conditions for which a trajectory will reach a smooth hypersurface. If the trajectories do not reach the sliding surface, then the system saturates. As such, the stability of the period-one orbit is lost. Using the conditions for existence and the concept of equivalent control, we show why, for the second closed-loop system, the onset of the fast-scale instability occurs when the inductor current approaches zero. For this system, we show that the onset of the fast-scale instability near zero-inductor current occurs for a lower line voltage. Besides, when the peak of the line voltage approaches the bus voltage, the fast-scale instability may occur not only at the peak but also when the inductor current approaches zero. We develop a condition which ensures that the saturated region does not have any stable orbits. As such, a solution that leaves the sliding surface (if existence fails) cannot stabilize in the saturated region. Finally, we extend the analysis to the case in which the converter operates with a finite but large switching frequency. As such, the system has two fundamental frequencies: the switching and line frequencies. Hence, the dynamics of the system evolve on a torus. We show two different approaches to obtaining a solution for the closed-loop system. For the second closed-loop system, using the controller gain for the current loop as a bifurcation parameter, we show (using a Poincaré map) the mechanism of the torus breakdown. If the mechanism of the torus breakdown is known, then, depending on the post-instability dynamics, a designer can optimize the design of the closed-loop converter.

Tuning the phase stability and surface HER activity of 1T′-MoS2 by covalent chemical functionalization

2020 ◽  
Vol 8 (44) ◽  
pp. 15852-15859
Author(s):  
Jiu Chen ◽  
Fuhua Li ◽  
Yurong Tang ◽  
Qing Tang
Keyword(s):  
Phase Stability ◽  
Chemical Functionalization ◽  
The Stability

Chemical functionalization can significantly improve the stability of meta-stable 1T′-MoS2 and tune the surface HER activity.

Random filters which preserve the stability of random inputs

1988 ◽  
Vol 20 (2) ◽  
pp. 275-294 ◽  
Author(s):  
Stamatis Cambanis
Keyword(s):  
Transfer Function ◽  
Moving Average ◽  
Random Processes ◽  
Time Shift ◽  
Linear Filter ◽  
Random Inputs ◽  
The Stability ◽  
Non Gaussian ◽  
Random Gain

A stationary stable random processes goes through an independently distributed random linear filter. It is shown that when the input is Gaussian or harmonizable stable, then the output is also stable provided the filter&s transfer function has non-random gain. In contrast, when the input is a non-Gaussian stable moving average, then the output is stable provided the filter&s randomness is due only to a random global sign and time shift.

Dynamic analysis and control of an active engine mount system

2002 ◽  
Vol 216 (11) ◽  
pp. 921-931 ◽  
Author(s):  
Y-W Lee ◽  
C-W Lee
Keyword(s):  
Transfer Function ◽  
Dynamic Characteristics ◽  
Performance Test ◽  
Adaptive Controller ◽  
Lms Algorithm ◽  
Equivalent Mass ◽  
Engine Mount ◽  
Active Engine ◽  
The Stability ◽  
Mass Spring

Dynamic characteristics of a prototype active engine mount (AEM), designed on the basis of a hydraulic engine mount, have been investigated and an adaptive controller for the AEM has been designed. An equivalent mass-spring-damper AEM model is proposed, and the transfer function that describes the dynamic characteristics of the AEM is deduced from mathematical analysis of the model. The damping coefficient of the model is derived by considering the non-linear flow effect in the inertia track. Experiments confirmed that the model precisely describes the dynamic characteristics of the AEM. An adaptive controller using the filtered-X LMS algorithm is designed to cancel the force transmitted through the AEM. The stability of the LMS algorithm is guaranteed by using the secondary path transfer function derived on the basis of the dynamic model of the AEM. The performance test in the laboratory shows that the AEM system is capable of significantly reducing the force transmitted through the AEM.

A New CRONE Suspension: More Compact and More Efficient: Part 2—Synthesis and Achievement

2009 ◽  
Author(s):  
Audrey Rizzo ◽  
Xavier Moreau ◽  
Alain Oustaloup ◽  
Vincent Hernette
Keyword(s):  
Transfer Function ◽  
Fractional Derivative ◽  
Vibration Isolation ◽  
Suspension System ◽  
Technological Parameters ◽  
Stability Degree ◽  
Parallel Arrangement ◽  
The Stability ◽  
Crone Suspension ◽  
The Ideal

In a vibration isolation context, fractional derivative can be used to design suspensions which allow to obtain similar performances in spite of parameters uncertainties. This paper presents the synthesis and the achievement of a new Hydractive CRONE suspension system. After the study of the different constraint in suspension in the first paper, the ideal transfer function of the hydractive CRONE suspension is created and simulated in different case. Then a method to determine the technological parameters is proposed. A parallel arrangement of dissipative and capacitive components and a gamma arrangement are compared. They lead to the same unusual performances: the stability degree robustness and the rapidity robustness.

scholarly journals Design and Simulation of a Capless Low Drop Out Voltage Regulator

2021 ◽  
pp. 69-75
Author(s):  
Babitha S ◽  
Mr. Hemanth Naidu K J ◽  
Mr. Ashwin Goutham G ◽  
Mr. Harshith S V
Keyword(s):  
High Performance ◽  
Primary Source ◽  
Operating Conditions ◽  
Drop Out ◽  
Voltage Regulator ◽  
Portable Devices ◽  
Current Amplifier ◽  
Power Resources ◽  
Error Amplifier ◽  
The Stability

Portable electronic devices mostly used battery as their primary source for operation hence longer running batteries or Power resources or vital for any portable device need for stable voltage supplies have led to the development of low dropout voltage regulators low dropout regulators provide stable regulated output voltage in various operating conditions which makes it useful in portable devices that design of high performance and stable low dropout voltage regulator is a challenge nowadays with decreasing device size and increasing power densities. The proposed circuit used a 5pack architecture of error amplifier. This paper proposes the study of behavior of the LDO voltage regulator with internal capacitors i.e., capless. The regulated voltage of 1.8V is obtained using the typical power supply of 2.2V obtained dropout voltage of 400mv with the delay of 12.77micro sec, power consumed 1.816W. The proposed design produced DC gain of 31.77db,with the load current variation of 0 to 20mA. The capless LDO architecture is verified in the Cadence 180nm technology. The architecture provides a stable gain and plot for both Temperature and Load Variations. The stability issues are overcome using the compensation techniques which uses a current amplifier and a capacitor in the differentiator configuration. The current amplifier implemented uses current mirror with current copying ratio of unity.

One-dimensional model for the Rijke tube

1989 ◽  
Vol 202 ◽  
pp. 83-96 ◽  
Author(s):  
C. Nicoli ◽  
P. Pelcé
Keyword(s):  
Heat Transfer ◽  
Transfer Function ◽  
Dimensional Model ◽  
Unsteady Heat Transfer ◽  
Order Unity ◽  
Rijke Tube ◽  
Thermoacoustic Instability ◽  
One Dimensional ◽  
The Stability ◽  
Stability Limits

We develop a simple model in which longitudinal, compressible, unsteady heat transfer between heater and gas is computed in the small-Mach-number limit. This calculation is used to determine the transfer function of the heater, which plays an important role in the stability limits of the thermoacoustic instability of the Rijke tube. The transfer function is determined analytically in the limit of small expansion parameter γ, and numerically for γ of order unity. In the case ρμ/cp = constant, an analytical solution can be found.

Phase Stability of the Sigma Phase in Fe-Cr Based Alloys

1995 ◽  
Vol 408 ◽  
Author(s):  
Marcel Il. F ◽  
Sluiter. Koivan Esfurjani ◽  
Yoshiyuki Kawazoe
Keyword(s):  
Total Energy ◽  
Phase Stability ◽  
First Principles ◽  
Finite Temperature ◽  
Sigma Phase ◽  
Complex Structure ◽  
Unit Cell ◽  
Energy Calculations ◽  
Cluster Variation ◽  
The Stability

AbstractThe FeCr sigma phase is a good example of a complex structure: it. has 30 atoms in the unit cell and 5 inequivalent lattice sites, and it belongs to the class of tetrahedrally close packed structures, also known as Frank-Kaspar structures. So far. such structures have riot been treated within a first-principles statistical thermodynamics framework. It will be shown that dtlme to advances in algorithms and hardware important features of the phase stability of complex phases can be computed. The factors which affect the stability of the sigma phase have been studied using carefully selected supercells for electronic total energy calculations. cluster variation calc:ulations in the tet.rahedron approximation were performed to evaluate the effect of partial disorder and of finite temperature. The preferred occupancy of the 5 lattice sites has been investigated and is compared with experimental determinations.

Graphical Hopf Bifurcation of a Filippov HTLV-1 Model With Delay in Cytotoxic T Cells Response

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Elham Shamsara ◽  
Zahra Afsharnezhad ◽  
Elham Javidmanesh
Keyword(s):  
T Cells ◽  
Hopf Bifurcation ◽  
Periodic Solutions ◽  
Bifurcation Theory ◽  
Cytotoxic T Cells ◽  
Dynamical Behavior ◽  
Bifurcation Theorem ◽  
Nyquist Criterion ◽  
The Stability ◽  
Frequency Domain Approach

In this paper, we present a discontinuous cytotoxic T cells (CTLs) response for HTLV-1. Moreover, a delay parameter for the activation of CTLs is considered. In fact, a system of differential equation with discontinuous right-hand side with delay is defined for HTLV-1. For analyzing the dynamical behavior of the system, graphical Hopf bifurcation is used. In general, Hopf bifurcation theory will help to obtain the periodic solutions of a system as parameter varies. Therefore, by applying the frequency domain approach and analyzing the associated characteristic equation, the existence of Hopf bifurcation by using delay immune response as a bifurcation parameter is determined. The stability of Hopf bifurcation periodic solutions is obtained by the Nyquist criterion and the graphical Hopf bifurcation theorem. At the end, numerical simulations demonstrated our results for the system of HTLV-1.

scholarly journals Coupling Influence on the dq Impedance Stability Analysis for the Three-Phase Grid-Connected Inverter

Energies ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3676
Author(s):  
Chuanyue Li ◽  
Taoufik Qoria ◽  
Frederic Colas ◽  
Jun Liang ◽  
Wenlong Ming ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Nyquist Plot ◽  
Current Control ◽  
Impedance Ratio ◽  
Three Phase ◽  
Grid Impedance ◽  
Nyquist Criterion ◽  
Grid Connected Inverter ◽  
The Stability ◽  
The Right

The dq impedance stability analysis for a grid-connected current-control inverter is based on the impedance ratio matrix. However, the coupled matrix brings difficulties in deriving its eigenvalues for the analysis based on the general Nyquist criterion. If the couplings are ignored for simplification, unacceptable errors will be present in the analysis. In this paper, the influence of the couplings on the dq impedance stability analysis is studied. To take the couplings into account simply, the determinant-based impedance stability analysis is used. The mechanism between the determinant of the impedance-ratio matrix and the inverter stability is unveiled. Compared to the eigenvalues-based analysis, only one determinant rather than two eigenvalue s-function is required for the stability analysis. One Nyquist plot or pole map can be applied to the determinant to check the right-half-plane poles. The accuracy of the determinant-based stability analysis is also checked by comparing with the state-space stability analysis method. For the stability analysis, the coupling influence on the current control, the phase-locked loop, and the grid impedance are studied. The errors can be 10% in the stability analysis if the couplings are ignored.

Sign in / Sign up

Export Citation Format

Share Document