scholarly journals Análisis de estabilidad de convertidores de segundo orden con la metodología de optimización de suma de polinomios cuadráticos

2020 ◽  
Vol 1 (1) ◽  
pp. 49-58
Author(s):  
Jhon Jairo Herrera-Pérez ◽  
Alejandro Garcés-Ruiz
Keyword(s):  
Output Voltage ◽  
Equilibrium Points ◽  
Linear Method ◽  
Pi Controller ◽  
Quadratic Lyapunov Function ◽  
Boost Converters ◽  
Dc Microgrids ◽  
Practical Applications ◽  
Simulation Results ◽  
The Stability

This paper presents a non-linear method based on sum-of-squares (SOS), to determine the stability of equilibrium points for the Buck, Boost, Buck-Boost and non-inverter Buck-Boost converters. These converters share a similar structure with a PI controller to regulate the output voltage. A quadratic Lyapunov function is proposed in all cases, and the conditions for stability are evaluated using convex optimization based on SOS models. The methodology is useful for academic purposes but also in practical applications like DC microgrids. Simulation results shows the advantages of the proposed method.

scholarly journals Equivalent Sliding Mode Controller for Stability of DC Microgrid

2021 ◽  
Vol 12 (1) ◽  
pp. 23
Author(s):  
Muhammad Rashad ◽  
Uzair Raoof ◽  
Nazam Siddique ◽  
Bilal Ashfaq Ahmed
Keyword(s):  
Reactive Power ◽  
Sliding Mode ◽  
Voltage Regulation ◽  
Pi Controller ◽  
Operating Conditions ◽  
Dc Microgrid ◽  
Dc Microgrids ◽  
Central Controller ◽  
The Stability ◽  
Decentralized Architecture

DC microgrids are gaining popularity due to their lack of reactive power compensation, frequency synchronization, and skin effect problems. However, DC microgrids are not exempted from stability issues. The stability of DC microgrids based on decentralized architecture is presented in this paper. Centralized architecture can degrade system performance and reliability due to the failure of a single central controller. Droop with proportional integral (PI) controller based on decentralized architecture is being used for DC microgrid stability. However, droop control requires a tradeoff between voltage regulation and droop gain. Further, global stability through PI controller cannot be verified and controller parameters cannot be optimized with different operating conditions. To address limitations, an equivalent sliding mode (SM) controller is proposed for a DC microgrid system in this paper. Detailed simulations are carried out, and results are presented, which show the effectiveness of an equivalent SM controller.

Fuzzy Parameter Based Mathematical Model on Forest Biomass

2018 ◽  
Vol 13 (04) ◽  
pp. 179-193 ◽  
Author(s):  
Prabir Panja
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Time Delay ◽  
Human Population ◽  
Equilibrium Points ◽  
Forest Biomass ◽  
Simulation Results ◽  
The Stability ◽  
Fuzzy Parameter

In this paper, a fuzzy mathematical model has been developed by considering forest biomass, human population and technological effort for the conservation of forest biomass as separate compartments. We have assumed that the forest biomass and human population grows logistically. We have considered that forest biomass decreases due to industrialization, food, shelter, etc., for humans. For the conservation of forest biomass, some modern technological efforts have been used in this model. Also, time delay of use of modern technological effort for the conservation of forest biomass has been considered on forest biomass. According to the assumptions, a fuzzy mathematical model on forest biomass is formulated. Next we have determined different possible equilibrium points. Also, the stability of our proposed system around these equilibrium points has been discussed. Finally, some numerical simulation results have been presented for better understanding of our proposed mathematical model.

CHAOS IN DIFFUSIONLESS LORENZ SYSTEM WITH A FRACTIONAL ORDER AND ITS CONTROL

2012 ◽  
Vol 22 (04) ◽  
pp. 1250088 ◽  
Author(s):  
YONG XU ◽  
RENCAI GU ◽  
HUIQING ZHANG ◽  
DONGXI LI
Keyword(s):  
Feedback Control ◽  
Control Problem ◽  
Fractional Order ◽  
Lorenz System ◽  
Equilibrium Points ◽  
Control Technique ◽  
Order System ◽  
System Parameters ◽  
Simulation Results ◽  
The Stability

This paper aims to investigate the phenomenon of Diffusionless Lorenz system with fractional-order. We discuss the stability of equilibrium points of the fractional-order system theoretically, and analyze the chaotic behaviors and typical bifurcations numerically. We find rich dynamics in fractional-order Diffusionless Lorenz system with appropriate fractional order and system parameters. Besides, the control problem of fractional-order Diffusionless Lorenz system is examined using feedback control technique, and simulation results show the effectiveness of the method.

scholarly journals Open-Circuit Fault-Tolerant Strategy for Interleaved Boost Converters via Filippov Method

Energies ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 352
Author(s):  
Cristina Morel ◽  
Ahmad Akrad ◽  
Rabia Sehab ◽  
Toufik Azib ◽  
Cherif Larouci
Keyword(s):  
Fault Tolerant ◽  
Open Circuit ◽  
Current Control ◽  
Mathematical Function ◽  
Stable Range ◽  
Boost Converters ◽  
Unique Model ◽  
Simulation Results ◽  
The Stability ◽  
First Time

Interleaved converters use an increased number of power electronics switches; this may subsequently affect their reliability. However, this is an opportunity to develop fault-tolerant strategies to improve their reliability and to ensure continuity of service. This is why we herein propose, for the first time, a mathematical function to simultaneously model the healthy and faulty conditions of each switch, thus enabling a unique model of the system. This model is then used in an original fault-tolerant strategy based upon the peak current control with slope compensation. This method not only extends the stable range of the load variation but also ensures the stability in faulty conditions. Finally, the simulation results validate its effectiveness and confirm the theoretical analysis.

A Novel Single Source Multiple Output Converter Integrating Buck-Boost and Fly Back Yopology for SMPS Applications

2017 ◽  
Vol 8 (3) ◽  
pp. 733 ◽  
Author(s):  
A. Kalirasu
Keyword(s):  
Duty Cycle ◽  
Power Supply ◽  
Output Voltage ◽  
Pi Controller ◽  
Single Source ◽  
Matlab Simulink ◽  
Boost Converters ◽  
Wide Range ◽  
Input Source ◽  
Switched Mode Power Supply

<p>This paper presents a novel single DC input source and multiple DC output suitable for switched mode power supply (SMPS) applications integrating interleaved boost and sepic converter with fly back topology. The proposed converter can be remodeled for any required output voltage power supply without changing hardware structure because wide range of output voltage can be obtained using sepic and boost converters by changing duty cycle command by implementing a simple voltage input pi controller. Conventional fly back topology is added to interleaved circuit to produce desired dc output voltage this voltage can be controlled by choosing turns ratio of fly back transformer. The proposed multi output DC converter is simulated in MATLAB/Simulink environment and results are presented for verifying merits of the converter.</p>

scholarly journals Chaotic Dynamics in a Novel COVID-19 Pandemic Model Described by Commensurate and Incommensurate Fractional-Order Derivatives

2021 ◽  
Author(s):  
Nadjette Debbouche ◽  
Adel Ouannas ◽  
Iqbal M. Batiha ◽  
Giuseppe Grassi
Keyword(s):  
Fractional Order ◽  
Chaotic Dynamics ◽  
Dynamic Behaviour ◽  
Equilibrium Points ◽  
Phase Portraits ◽  
The Novel ◽  
Fractional Order Differential Equations ◽  
Simulation Results ◽  
The Stability ◽  
Nonlocal Nature

Abstract Mathematical models based on fractional-order differential equations have recently gained interesting insights into epidemiological phenomena, by virtue of their memory effect and nonlocal nature. This paper investigates the nonlinear dynamic behaviour of a novel COVID-19 pandemic model described by commensurate and incommensurate fractional-order derivatives. The model is based on the Caputo operator and takes into account the daily new cases, the daily additional severe cases and the daily deaths. By analysing the stability of the equilibrium points and by continuously varying the values of the fractional order, the paper shows that the conceived COVID-19 pandemic model exhibits chaotic behaviours. The system dynamics are investigated via bifurcation diagrams, Lyapunov exponents, time series and phase portraits. A comparison between integer-order and fractional-order COVID-19 pandemic models highlights that the latter is more accurate in predicting the daily new cases. Simulation results, besides to confirm that the novel fractional model well fit the real pandemic data, also indicate that the numbers of new cases, severe cases and deaths undertake chaotic behaviours without any useful attempt to control the disease.

scholarly journals Voltage tracking of bridgeless PFC cuk converter using PI controller

2020 ◽  
Vol 11 (1) ◽  
pp. 367
Author(s):  
W. M. Utomo ◽  
N. A. A. Isa ◽  
A. A. Bakar ◽  
A. F. H. A. Gani ◽  
B. E. Prasetyo ◽  
...  
Keyword(s):  
Steady State ◽  
Power Factor ◽  
Output Voltage ◽  
Pi Controller ◽  
Step Response ◽  
Pi Control ◽  
Control Voltage ◽  
Cuk Converter ◽  
Proportional Integral ◽  
Simulation Results

This paper proposes a Proportional-Integral (PI) control voltage tracking of Bridgeless Power Factor Correction (BPFC) Cuk converter.  In order to investigate the behaviour of different output voltages during overshoot, steady state and step response, P.I controller is designed to set the -42 V, -48 V, -54 V output voltages. The simulation results show that the proposed PI controller able to control the output voltage and achieve fast steady state and step response of BPFC Cuk converter.  When the value of output voltage increase, the overshoot voltage will become higher but the steady state respond will be faster. Furthermore, BPFC Cuk converter with P.I controller have low output voltage ripples.

Stabilization of a Quadrotor With Uncertain Suspended Load Using Sliding Mode Control

2016 ◽  
Author(s):  
Xu Zhou ◽  
Rui Liu ◽  
Jiucai Zhang ◽  
Xiaoli Zhang
Keyword(s):  
Sliding Mode ◽  
Suspended Load ◽  
Pd Controller ◽  
Practical Applications ◽  
Uncertain Disturbances ◽  
Mass Uncertainty ◽  
Simulation Results ◽  
The Stability ◽  
Quadrotor System ◽  
Load Mass

The stability and trajectory control of a quadrotor carrying a suspended load with a fixed known mass has been extensively studied in recent years. However, the load mass is not always known beforehand in practical applications. This mass uncertainty brings uncertain disturbances to the quadrotor system, causing existing controllers to have a worse performance or to be collapsed. To improve the quadrotor’s stability in this situation, we investigate the impacts of the uncertain load mass on the quadrotor. By comparing the simulation results of two controllers — the proportional-derivative (PD) controller and the sliding mode controller (SMC) driven by a sliding mode disturbance of observer (SMDO), the quadrotor’s performance is verified to be worse as the uncertainty increases. The simulation results also show a controller with stronger robustness against disturbances is better for practical applications.

scholarly journals PI Control of Current-Fed Dual Active Bridge Converter for DC Microgrid

2019 ◽  
Vol 8 (9S3) ◽  
pp. 283-288
Keyword(s):  
State Space ◽  
Averaging Method ◽  
Controller Design ◽  
Pi Controller ◽  
Pi Control ◽  
Dc Microgrid ◽  
Line Load ◽  
Dual Active Bridge ◽  
Simulation Results ◽  
The Stability

A detailed modelling of soft-switching isolated current-fed dual active bridge (CFDAB) DC/DC converter is presented. This converter is suitable for an interface between two DC buses in a microgrid but is not controlled. The model of the converter is derived with the help of state space averaging method. Based on this modelling, the PI controller designed to improve the operation of the CFDAB converter. Simulation results using MATLAB/Simulink with controller design to verify the stability of the converter and validated performance of the system used for DC microgrid applications of between two buses. The effectiveness of the controller has justified in terms of line, load variation and tracking the reference values.

scholarly journals Parametric Controller Design of Hopf Bifurcation System

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Jinbo Lu ◽  
Xiaorong Hou ◽  
Min Luo
Keyword(s):  
Computer Simulation ◽  
Hopf Bifurcation ◽  
Nonlinear Dynamic ◽  
Lorenz System ◽  
Controller Design ◽  
Design Method ◽  
Equilibrium Points ◽  
Nonlinear Dynamic System ◽  
Simulation Results ◽  
The Stability

A general parametric controller design method is proposed for Hopf bifurcation of nonlinear dynamic system. This method does not increase the dimension of the system. Compared with the existing methods, the controller designed by this method has a lower controller order and a simpler structure, and it does not contain equilibrium points. The method keeps equilibrium of the origin system unchanged. Symbolic computation is used to deduce the constraints of controller, and cylindrical algebraic decomposition is used to find the stability parameter regions in parameter space of controller. The method is then employed for Hopf bifurcation control. Taking Lorenz system as an example, the controller design steps of the method and numerical simulations are discussed. Computer simulation results are presented to confirm the analytical predictions.

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