Attila Magyar

Attila Magyar
University of Pannonia, Veszprém · Department of Electrical Engineering and Information Systems

PhD

About

77
Publications
13,726
Reads
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315
Citations
Introduction
Attila Magyar currently works at the Department of Electrical Engineering and Information Systems, University of Pannonia, Veszprém. Attila does research in Control Systems Engineering.
Skills and Expertise
Additional affiliations
November 2012 - present
University of Pannonia, Veszprém
Position
  • TÁMOP-4.2.2.A-11/1/KONV-2012-0072
Description
  • Energy efficiency project
February 2010 - present
University of Pannonia, Veszprém
Position
  • Robotics
Description
  • Robotics subject for BSc students (mechanical engineers, electrical engineers, computer science)
February 2009 - present
University of Pannonia, Veszprém
Position
  • Computer controlled systems
Description
  • Control theory course for MSc students in computer science
Education
September 2004 - June 2007
University of Pannonia, Veszprém
Field of study
  • information science
September 1999 - June 2004
University of Pannonia, Veszprém
Field of study
  • information technology

Publications

Publications (77)
Article
Full-text available
Fast charging is an attractive way of charging batteries; however, it may result in an undesired degradation of battery performance and lifetime because of the increase in battery temperature during fast charge. In this paper we propose a simple optimized fuzzy controller that is responsible for the regulation of the charging current of a battery c...
Article
Full-text available
Balancing in a distributed generation network is an increasingly difficult task because of the increasing number of residential prosumers on the power network. This paper proposes a framework for the estimation, as well as the prediction of the power flexibility of residential prosumers. In order to quantify the residential buildings’ demand flexib...
Article
Full-text available
This study approaches the stability analysis and controller design of Lotka–Volterra and quasi-polynomial systems from the perspective of passivity theory. The passivity based approach requires to extend the autonomous system model with a suitable input structure. The condition of passivity for Lotka–Volterra systems is less strict than the classic...
Conference Paper
Full-text available
In this paper a non-technical loss (NTL) diagnostic method is proposed which considers faults at unregistered points in the distribution network. The method relies on the concept of smart grid, where every consumer is equipped with smart meters. Existing line segments are split up in order to detect and isolate faults at arbitrary points between me...
Article
Full-text available
Persistent faults are steady state anomalies with a magnitude which does not necessary trigger general protective gear. It is present in various types of distribution networks, as leak in pipe networks or as high-impedance fault in electric systems. As smart meters come into general use, distribution systems are upgraded to have advanced metering i...
Article
Full-text available
Parameter estimation of electrical vehicle batteries in the presence of temperature effect is addressed in this work. A simple parametric temperature dependent battery model is used for this purpose where the temperature dependence is described by static relationships. A two-stepmethod is used that includes a parameter estimation step of the key pa...
Article
Generalized mass action systems are general descriptors in the sense that they are able to capture the structure and dynamic properties of chemical reaction networks even in intracellular environments. It has been shown that several results of chemical reaction network (CRN) theory carry over to the case of generalized mass action kinetics. It is k...
Article
Full-text available
A cost-optimal model predictive scheduling algorithm is presented that operates in a day-ahead market. The underlying optimizer is a heuristic branch and bound algorithm that finds the constrained optimal scheduling of a freezer with respect to hourly changing energy price. The method is also able to iteratively re-estimate the heat capacity of the...
Book
Analysis and Control of Polynomial Dynamic Models with Biological Applications synthesizes three mathematical background areas (graphs, matrices and optimization) to solve problems in the biological sciences (in particular, dynamic analysis and controller design of QP and polynomial systems arising from predator-prey and biochemical models). The bo...
Article
Li-ion batteries are widely used in EV applications and are imposed to several aging effects during their lifetime. Since battery health cannot be measured directly, information about its health can be obtained by iteratively re-estimating the parameters of the model describing its dynamical behavior. The optimal design of experiments is investigat...
Conference Paper
Full-text available
A parameter estimation study is reported here to estimate the temperature-dependent internal resistance of a lithium ion battery that is connected to the state of its health.A simple equivalent electrical circuit model was used for this purpose that is nonlinear both in its variables and in its parameters. Parameter sensitivity analysis showed tha...
Article
Full-text available
A novel heuristic model-based optimal scheduling algorithm is proposed in this paper to operate heating and cooling type home appliances connected to smart grids where the price of the electrical energy is known in advance and temperature constraints are present. The properties and the use of the proposed algorithm are shown using a simple refriger...
Article
This work applies the LQ control framework to the class of quasi-polynomial and Lotka-Volterra systems through the linearized version of their nonlinear system model. The primary aim is to globally stabilize the original system with a suboptimal LQ state feedback by means of a well-known entropy-like Lyapunov function that is related to the diagona...
Article
Full-text available
The cost optimal scheduling of a household refrigerator is presented in this work. The fundamental approach is the model predictive control methodology applied to the piecewise affine model of the refrigerator. The optimisation could not be solved using off-the-shelf tools, e.g. Multi-Parametric Toolbox, so a binary treebased optimal scheduling alg...
Article
Full-text available
A current source inverter model has been developed in the given paper that is constructed from six LTI models for the different switching modes. The overall model is in a piecewise affine form that supports the use of model predictive control. The model has been verified against engineering expectations and its open-loop performance shows that it i...
Article
Voltage unbalance is a major yet often overlooked power quality problem in low voltage residential feeders due to the random location and rating of single-phase renewable sources and uneven distribution of household loads. This paper proposes a new indicator of voltage deviation that may serve as a basis of analysis and compensation methods in this...
Article
Using translated X-factorable phase space transformations and nonlinear variable transformations a dynamically similar linear ODE model is associated to the Lotka-Volterra system models with a positive equilibrium point. This enables to use a linear full state feedback controller to stabilize the system in controllable cases, that leaves the open l...
Article
Full-text available
The three-phase unbalance problem can introduce additional losses in distribution networks due to both negative and zero sequence components, which leads to inefficient power consumption and increased CO2 emission of low voltage transformer area, moreover it causes safety possible malfunction of energy transportation networks. The aim of this paper...
Conference Paper
Full-text available
The three-phase unbalance problem is a familiar issue. It can introduce additional power losses in distribution networks due to both negative and zero sequence components. It could also limit the loading capability of distribution transformers , well below their nominal ratings. There are many voltage unbalance definitions for three-phase three-wir...
Article
A measurement based model of hydrogen generating cell for simulation of complex energy system is described in this paper. The model parameter estimation has been performed based on measurement data obtained during the detailed examination of a demonstration cell. A series of experiments has been carried out on a HHO (Oxyhydrogen) gas producing dry...
Article
Two partially overlapping classes of positive polynomial systems, chemical reaction networks with mass action law (MAL-CRNs) and quasi-polynomial systems (QP systems) are considered. Both of them have an entropy-like Lyapunov function associated to them which are similar but not the same. Inspired by the work of Prof. Gorban [12] on the entropy-fun...
Article
Full-text available
—A multiple-input–multiple-output linear-quadratic servo controller is proposed for a synchronous generator operating in a nuclear power plant that keeps the active power at the desired level and performs reactive power reference tracking using the reactive power demand from a central dispatch center. The controller design was based on the locally...
Article
Full-text available
An experimental study is presented in this work, where the distortion effect of a 4 kW photovoltaic domestic power plant, located in Hungary, has been examined. The power plant is connected to a low voltage grid by using a standard grid synchronized inverter. Based on the measured voltage and current signals we examined the frequency domain behavio...
Article
Full-text available
Nowadays, the growing need for energy from renewable sources and growing revulsion towards fossil and nuclear fuels puts sustainable and green energy in the limelight. Producing (electrical) energy in domestic power plants from renewable sources (mainly solar and wind) hardly results in difficulties, but the storage of energy not consumed immediate...
Article
Full-text available
A simple kinematic model of a differential steering mobile robot is investigated in this work using a nonlinear technique based on the quasi-polynomial representation of the dynamical model. Dynamical systems with can be embedded to the so-called generalized Lotka-Volterrs (or quasi-polynomial) form under mild conditions. Quasi-polynomial systems a...
Article
Full-text available
Nowadays, the growing need for energy from renewable sources and growing revulsion towards fossil and nuclear fuels turns sustainable and green energy in the foreground. Producing (electrical) energy from renewable sources hardly means difficulties but the storage of the energy not consumed immediately is a great engineering challenge. In the prese...
Conference Paper
Based on the underlying dynamically similar linear system of a quasi-polynomial (QP) system [7], a dynamic feedback controller for single input QP systems is proposed in this work that can locally stabilize the closed-loop system using a pre-defined quadratic control Lyapunov function. Since the parameter matrix of the dynamically similar reduced l...
Conference Paper
The aim of this work is to present an entropy-like Lyapunov function based dynamic feedback design technique for quasi-polynomial and Lotka-Volterra systems. It is shown, that the dynamic feedback design problem is equivalent to the feasibility of a bilinear matrix inequality. The problem is also formulated as a control Lyapunov function based feed...
Conference Paper
A control method for improving the power quality in low voltage network contains mainly LED Light Sources with simple nonlinear switching power supply is described in this paper. This method implements active power factor correction and lowers the voltage and current extant harmonic distortion in the line. The novel element in the proposed structur...
Conference Paper
Full-text available
A case study is presented in this work, where a 4 kW photovoltaic domestic power plant, located in Hungary, has been examined. Based on the measured voltage and current signals we examined the frequency domain behaviour of the power plant and the effect to the power quality, mainly the total harmonic distortion, of the low voltage transformer area....
Article
This paper describes a low-voltage grid composed of small, domestic power plants fueled by clean and renewable energy sources and augmented with electric vehicle batteries as power storage devices. We propose that this grid could utilize a complex multifunctional control unit capable of optimizing the working point and charging current of the syste...
Article
The paper presents a general temperature-dependent model for a family of batteries developed for electrical vehicle (EV) use. In addition to the model's derivation, the methodology and instruments developed to accurately measure the temperature-dependent parameters are also presented together with a Matlab/Simulink block for a temperature-dependent...
Conference Paper
Full-text available
A multiple-input multiple-output (MIMO) LQ servo controller was proposed for an industrial size synchronous generator that keeps the active power at the desired level and performs reactive power reference tracking using the reactive power demand from the central dispatch center. The controller design was based on the locally linearized version of a...
Conference Paper
The increase of renewable power sources in today's energy production systems results in high non-deterministic fluctuations in energy distribution network. At the same time, the use of nonlinear switching power supplies is more and more widespread nowadays, that creates serious nonlinear distortion in the line. In addition, the insufficient energy...
Conference Paper
In the recent years, more and more important research and development projects are aimed to the modernization of vehicle energy supply and to find an alternative of fossil energy sources. One of these alternatives is the family of vehicles powered by purely electric energy. Besides its advantages, the main disadvantage of this solution is that the...
Article
Full-text available
A simple dynamic model of a synchronous motor is developed in this paper based on first engineering principles that describe the mechanical phenomena together with the electrical model. The constructed state space model consists of nonlinear state equations and bi-linear output equations. The developed model has been verified under the usual regula...
Conference Paper
Full-text available
A control method for small domestic power plants using renewable energy is described in this paper. This method is not only capable of optimizing the working point of the plant but also implements active power factor correction and lowers the extant harmonic distortion in the line. The novel element in the proposed complex controller structure is t...
Conference Paper
Full-text available
A simple dynamic model of an industrial size synchronous generator operating in a nuclear power plant is developed in this paper based on first engineering principles. The constructed state-space model consists of a nonlinear state equation and a bi-linear output equation. It has been shown that the model is locally asymptotically stable with param...
Article
Full-text available
Convective, hot air drying by itself is relatively efficient for removing water from the surface environment of agricultural seed products. However, moving internal moisture to the surface needs rather a long time, as a rule. The major research aim of the authors was to decrease the processing time and processing costs, to improve the quality of th...
Article
An indirect measurement scheme is used in this paper, which allows us to to optimally select the elements of the measurement protocol according to a predefined weighting between the variance of the estimated state parameters and the ratio of the non-demolished copies of the system.
Article
In the present paper a globally stabilizing feedback controller design method is proposed for process systems when the feedback structure is also assumed to be in a quasi-polynomial form. It is shown that such feedback structure can always be achieved for process systems.By exploiting the special structure of the controller design problem, the exis...
Thesis
Full-text available
The goal of this dissertation is to apply system and control theory to two system classes originating from different fields of physics: process systems and quantum mechanical systems. Using the quasi-polynomial system representation it is possible to describe the dynamic behavior of general nonlinear process systems. It is shown in the work, that g...
Article
Full-text available
The estimation of the density matrix of a $k$-level quantum system is studied when the parametrization is given by the real and imaginary part of the entries and they are estimated by independent measurements. It is established that the properties of the estimation procedure depend very much on the invertibility of the true state. In particular, in...
Conference Paper
In this paper a Bayesian approach for estimating the state of a qubit is proposed. It consists of two phases. First a component-wise separate Bayesian estimate of the Bloch vector components is calculated in the form of β-distributions. Then a regularization step is performed to respect the constraint that the Bloch vector must be in the unit ball....
Article
Full-text available
Nonlinear input-affine systems in quasi-polynomial (QP) and Lotka-Volte rra (LV) forms are investigated in this paper. It is shown that both the global stability analysis with an entropy-like Lyapunov function candidate and the lo- cal quadratic stability region determination can be performed by solving lin- ear matrix inequalities (LMIs). The inva...
Article
Full-text available
In the paper the Bayesian and the least squares methods of quantum state tomography are compared for a single qubit. The quality of the estimates are compared by computer simulation when the true state is either mixed or pure. The fidelity and the Hilbert-Schmidt distance are used to quantify the error. It was found that in the regime of low measur...
Article
The application of quasi-polynomial system representation for the analysis and control of a wide class of smooth nonlinear systems is proposed in this paper. The analysis part includes the global stability analysis of the open loop system and that of the zero dynamics. It is shown that the stabilizing controller design with monomial feedback struct...
Article
In this Letter we show that an important type of time-reparametrization problem in quasi-polynomial systems is equivalent to the feasibility of a suitably constructed bilinear matrix inequality where the unknowns are the coefficients of the Lyapunov function and the exponents in the time-reparametrization transformation.
Conference Paper
Full-text available
Quantum mechanics is one of the most interesting field in mode rn physics. In spite of its great importance related to quantum computers and quantum information theory, just a few person has tried to use the tools of control theory for quantu m systems. In quantum mechanics the nature of measuring is very different from measuring in classical physi...
Article
The global and local stability of process systems in generalized Lotka-Volterra form is studied in this paper using entropy-like and quadratic Lyapunov function candidates. The global stability check for LV models is performed by solving an LMI for a diagonal positive semi-definite matrix using singular perturbation technique. It is shown that a qu...
Conference Paper
Full-text available
1 Problem statement The global stability analysis of general nonlinear systems needs special skills because the construction of a suitable Lyapunov is far from being trivial. Therefore special canonical forms of general nonlinear systems enabling to construct a Lyapunov function are of great theoretical and practical importance. Generalized Lotka-V...
Article
Full-text available
A simple dynamic model of an industrial size synchronous generator operating in a nuclear power plant is developed in this paper based on first engineering principles. The constructed state-space model consists of an LTI state equation and a bi-linear output equation. It has been shown that the model is asymptotically stable with parameters obtaine...
Article
Full-text available
The properties of the indirect measurement scheme is investigated in this report in the discrete time case. The simplest possible case is considered, where both the unknown and the measurement quantum systems are quantum bits. The measurements applied on the measurement qubit are the classical von Neumann measurements using the Pauli matrices as ob...
Article
Full-text available
A previously developed simple dynamic model of an industrial size synchronous generator operating in a nuclear power plant is analyzed in this paper. The constructed state-space model consists of a nonlinear state equation and a bi-linear output equation. It has been shown that the model is locally asymptotically stable with parameters obtained fro...