Editorial

2 pages, 168 KiB

Open AccessEditorial

Advanced Perspectives for Modeling Simulation and Control of Power Electronic Systems

by Michal Frivaldsky

Energies 2021, 14(23), 8108; https://doi.org/10.3390/en14238108 - 03 Dec 2021

Viewed by 846

Power electronic systems have become a major issue related to advancements in consumer and industrial electronics [...] Full article

(This article belongs to the Special Issue Advanced Perspectives for Modeling, Simulation and Control of Power Electronic Systems)

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19 pages, 1020 KiB

Open AccessArticle

Collective Losses of Low Power Cage Induction Motors—A New Approach

by Elzbieta Szychta and Leszek Szychta

Energies 2021, 14(6), 1749; https://doi.org/10.3390/en14061749 - 22 Mar 2021

Cited by 6 | Viewed by 1647

Abstract

Energy efficiency of systems of water pumping is a complex problem since efficiency of two distinct interacting systems needs to be combined: water and power supply. This paper introduces a non-intrusive method of calculating the so-called “collective losses” of a cage induction motor. [...] Read more.

Energy efficiency of systems of water pumping is a complex problem since efficiency of two distinct interacting systems needs to be combined: water and power supply. This paper introduces a non-intrusive method of calculating the so-called “collective losses” of a cage induction motor. The term “collective losses”, which the authors define, allows for accurate estimation of motor efficiency. Control system of a pump determines operating point of a pumping station, and thus its efficiency. General estimated performance characteristics of a motor, components of a control system, are assumed to serve selection of a range of pumping speed variations. Rotational speed has a direct effect on motor load torque, pump power and head, and thus on motor performance. Hellwig’s statistical method was used to specify characteristics of estimated collective losses on the basis of experimental studies of 21 motors rated at up to 2.2 kW. The results of simulations and experiments are used to verify validity and efficiency of the suggested method. The method is non-intrusive, simple to use, and requires minimum data. Full article

(This article belongs to the Special Issue Advanced Perspectives for Modeling, Simulation and Control of Power Electronic Systems)

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12 pages, 2267 KiB

Open AccessArticle

Analysis of Influence Factors for Heat Generation Minimization of DC-Link Capacitor

by Yong Won Jeon, Young Shin Kim and Euy Sik Jeon

Energies 2021, 14(1), 114; https://doi.org/10.3390/en14010114 - 28 Dec 2020

Cited by 3 | Viewed by 3246

Abstract

With the rapid development of ecofriendly cars, various inverters are also being developed depending on the performance of motors. The DC-link capacitor is used as an inverter component; however, there are several limitations on its size, such as the requirement for wide films. [...] Read more.

With the rapid development of ecofriendly cars, various inverters are also being developed depending on the performance of motors. The DC-link capacitor is used as an inverter component; however, there are several limitations on its size, such as the requirement for wide films. Film width is a major factor that affects the capacitor’s equivalent series resistance (ESR) and is closely related to heat generation. When the temperature of the capacitor increases, the dielectric breakdown due to high voltage causes a reduction in capacitance, which leads to a decrease in inverter power and causes vehicle defects; this needs to be addressed to minimize the heat of the capacitor. Recently, genetic films that can be used at high temperatures have been developed. However, producing such films is difficult because of their 5 µm thickness; thus, the size increases when they are designed and they consequently cannot be used in practical applications. Based on a film width of 50 mm, this study analyzed the factors that can reduce ESR, set the level for each factor, and conducted experiments using the Box–Behnken design. The variables (thermal conductivity, film thickness, and capacitance) were set to three levels for each factor, and the ESR, thermal flux, and temperature characteristics were analyzed through finite element analysis. Based on the temperature results, optimized conditions for film thickness of 3.15 μm, capacitance of 390 μF, and thermal conductivity epoxy of 4.5 W/m·K were derived using Minitab, and samples were made for verification tests. A capacitor was installed in the chamber and was saturated for 2 h at 85 °C and current of 50 A rms was applied at 16 kHz frequency. The K Type sensor attached to the film surface was connected to a temperature recorder to measure the temperature change in the film over time after applying the current. The experimental results confirmed that the temperature of the genetic film with a 50 mm film width was similar to that with a 35 mm film width, and this confirmed that the set factors were similar to that of the genetic film with 35 mm film width. It was confirmed that increased film width can reduce ESR and minimize heat generation. Full article

(This article belongs to the Special Issue Advanced Perspectives for Modeling, Simulation and Control of Power Electronic Systems)

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18 pages, 6613 KiB

Open AccessArticle

In Loop Design of the Coils and the Electromagnetic Shielding Elements for the Wireless Charging Systems

by Michal Frivaldsky and Miroslav Pavelek

Energies 2020, 13(24), 6661; https://doi.org/10.3390/en13246661 - 17 Dec 2020

Cited by 14 | Viewed by 2501

Abstract

This paper deals with in loop design of coupling elements of the wireless charging systems (WChS). The in-loop design is created as a script/User Interface (UI) in MATLAB environment, which is based on finite element models of WChS. Main aim of developed tool [...] Read more.

This paper deals with in loop design of coupling elements of the wireless charging systems (WChS). The in-loop design is created as a script/User Interface (UI) in MATLAB environment, which is based on finite element models of WChS. Main aim of developed tool is to easily identify the optimal geometrical parameters of the coupling coils. The optimization of the coil’s geometrical and electrical parameters is specified by an algorithm, which is based on definition for transfer of required amount of power and on geometrical restrictions of the target application. The second part of the proposed script/UI is used for user guided design of the electromagnetic shielding. It enables to optimize the shielding parameters in order to reach the limits defined by international standards for safety levels with respect to human exposure. Proposed design methodology together with user interface have been verified though experimental validation. For this purpose, construction of WChS was realized based on the results from in loop design process. Comparisons have been made according to the evaluation of simulation model´s accuracy, that is, the values of self-inductances, mutual inductances, coupling coefficient and gain characteristics have been evaluated (simulations vs. experiments). At the end of the paper the evaluation of the shielding performance was realized, while once more the comparison between simulation and experiments have been made. Received results are showing less than 2% of the relative error. Using presented methodology, the fast optimization actions can be done during design and modelling of WChS. Full article

(This article belongs to the Special Issue Advanced Perspectives for Modeling, Simulation and Control of Power Electronic Systems)

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47 pages, 14980 KiB

Open AccessArticle

Analysis and Design Guidelines for Current Control Loops of Grid-Connected Converters Based on Mathematical Models

by Gonzalo Abad, Alain Sanchez-Ruiz, Juan José Valera-García and Aritz Milikua

Energies 2020, 13(21), 5849; https://doi.org/10.3390/en13215849 - 09 Nov 2020

Cited by 5 | Viewed by 2095

Abstract

Having a method for analyzing and designing regulators of controls that contain many current loops such as active filters is not a trivial task. There can be many parameters of regulators and filters that must be carefully selected in order to fulfill certain [...] Read more.

Having a method for analyzing and designing regulators of controls that contain many current loops such as active filters is not a trivial task. There can be many parameters of regulators and filters that must be carefully selected in order to fulfill certain desired requirements. For instance, these can be stability, dynamic response, robustness under uncertainty of parameters, and rejection capability to switching harmonics. Hence, this paper provides general analysis guidelines for designing current control loops by using mathematical models in an αβ reference frame. Then, by using the proposed modeling tool, a multi-objective tuning algorithm is proposed that helps obtain all the control loops’ regulator and filter parameters, meeting all the desired requirements. Thus, the proposed analysis and design methodology is illustrated by applying it to three different controls conceived in a dq rotating reference frame with PI (Proportional Integral) regulators. The first control presents two current loops (simple dq current control), the second control uses four current loops (dual vector control, for unbalanced loads), while the third control presents eight current loops (active filter controlling current harmonics). Several experimental and simulation results show the effectiveness and usefulness of the proposed method. Since the mathematical model employed is in the αβ reference frame, it can also be easily applied to controls conceived in a αβ reference frame using resonant regulators, providing also a common comparative framework. Full article

(This article belongs to the Special Issue Advanced Perspectives for Modeling, Simulation and Control of Power Electronic Systems)

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16 pages, 7996 KiB

Open AccessArticle

Optimal Combination Design of a Light Emitting Diode Matrix Applicable to a Single-Stage Flyback Driver

by Ming-Chang Tsou and Ming-Tse Kuo

Energies 2020, 13(19), 5209; https://doi.org/10.3390/en13195209 - 06 Oct 2020

Cited by 4 | Viewed by 1947

Abstract

The present study analyzed light emitting diodes (LEDs) as an output load and used a Taylor series to describe the characteristic curve based on the exponential characteristic of voltage and current. A prototype circuit of a flyback LED driver system was established to [...] Read more.

The present study analyzed light emitting diodes (LEDs) as an output load and used a Taylor series to describe the characteristic curve based on the exponential characteristic of voltage and current. A prototype circuit of a flyback LED driver system was established to verify whether the theory is consistent with actual results. This study focused on the exponential relationship of LED voltage and current. Conventional simulations usually used linear models to present LED loads. However, the linear model resulted in considerable error between simulation and actual characteristics. Therefore, this study employed a Taylor series to describe the nonlinear characteristic of an LED load. Through precise calculations with Mathcad computation software, the error was effectively reduced. Moreover, the process clarified the influence of temperature on LEDs, which benefited the characteristic analysis of the entire system. Finally, a realized circuit of 120 W flyback LED drivers was established for conducting theory verification, including theoretic analysis and evaluation of the system design process of the flyback converter. The circuit simulation software SIMPLIS was used to demonstrate the system model, which enabled quick understanding of the system framework established in this study. Regarding LEDs, a commercially available aluminum luminaire was used as the output load. The measured results of the actual circuit and the simulation results were remarkably consistent. For the same system at the same temperature, the error between the simulation and actual results was less than 3%, which proved the reliability of the Taylor series simulation. Full article

(This article belongs to the Special Issue Advanced Perspectives for Modeling, Simulation and Control of Power Electronic Systems)

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22 pages, 6343 KiB

Open AccessArticle

Modeling of a Quasi-Resonant DC Link Inverter Dedicated to Common-Mode Voltage and Ground Current Reduction

by Marek Turzyński and Michal Frivaldsky

Energies 2020, 13(19), 5090; https://doi.org/10.3390/en13195090 - 29 Sep 2020

Cited by 3 | Viewed by 1830

Abstract

In this paper, the modeling methodology of the AC drive system with a Parallel Quasi-Resonant DC Link Inverter (PQRDCLI) is described. A presented modeling approach is an attractive tool used for the effective evaluation of a common-mode (CM) voltage and grounds current reduction [...] Read more.

In this paper, the modeling methodology of the AC drive system with a Parallel Quasi-Resonant DC Link Inverter (PQRDCLI) is described. A presented modeling approach is an attractive tool used for the effective evaluation of a common-mode (CM) voltage and grounds current reduction methods. Designed models of inverter, induction machine (IM), and cable are simple, thus the methods for parameter extraction are not complicated. Verification of the proposed modeling approach was realized with the use of the the Synopsys (Mountain View, CA, USA) SABER simulator, while simulation results were experimentally verified. Operation principles of the proposed PQRDCLI converter topology are also described. Based on simulation and experimental results, it was confirmed that the proposed PQRDCLI solution represents required performance within the reduction of common-mode voltage and ground current in electric drives. Moreover, comparisons from a simulation complexity point of view have been performed to the existing methods. The evaluation is being shown at the end of the paper. It is confirmed that the presented method is simple, fast, accurate, and robust as well. Full article

(This article belongs to the Special Issue Advanced Perspectives for Modeling, Simulation and Control of Power Electronic Systems)

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18 pages, 3735 KiB

Open AccessArticle

A Corrected Equilibrium Manifold Expansion Model for Gas Turbine System Simulation and Control

by Linhai Zhu, Jinfu Liu, Yujia Ma, Weixing Zhou and Daren Yu

Energies 2020, 13(18), 4904; https://doi.org/10.3390/en13184904 - 18 Sep 2020

Cited by 7 | Viewed by 1653

Abstract

During recent decades, the equilibrium manifold expansion (EME) model has been considered as a powerful identification tool for complex industrial systems with the aim of system control and simulation. Based on a two-step “dynamic and static” identification method, an approximate nonlinear state-space model [...] Read more.

During recent decades, the equilibrium manifold expansion (EME) model has been considered as a powerful identification tool for complex industrial systems with the aim of system control and simulation. Based on a two-step “dynamic and static” identification method, an approximate nonlinear state-space model is built by using multiple polynomials. However, the existing identification method is only suitable for single-input (SI) systems, but not for multi-input (MI) systems, where EME models cannot guarantee global calculation stability. For solving such a problem, this paper proposes a corrected equilibrium manifold expansion (CEME) model based on gas turbine prior knowledge. The equilibrium manifold is extended in dimension by introducing similarity equations instead of the high dimensional polynomial fitting. The dynamic similarity criterion of similarity theory guarantees the global stability of the CEME model. Finally, the comparative test between the CEME model and the existing MI-EME model is carried out through case studies involving data that are generated by a general turbofan engine simulation. Simulations show superior precision and calculation stability of the proposed model in capturing nonlinear behaviors of the gas turbine engine. Full article

(This article belongs to the Special Issue Advanced Perspectives for Modeling, Simulation and Control of Power Electronic Systems)

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16 pages, 4131 KiB

Open AccessArticle

A Study of Interpolation Compensation Based Large Step Simulation of PWM Converters

by Yahui Li, Pu Deng, Jing Zhang, Donghang Liu and Zhenghang Hao

Energies 2020, 13(12), 3069; https://doi.org/10.3390/en13123069 - 13 Jun 2020

Cited by 2 | Viewed by 1761

Abstract

Real-time online simulation based on a real-time workshop (RTW) plays a vital role in the study and application of power electronics. However, restricted by the performance of equipment and hardware, the simulators so far available in the market mainly support simulation steps over [...] Read more.

Real-time online simulation based on a real-time workshop (RTW) plays a vital role in the study and application of power electronics. However, restricted by the performance of equipment and hardware, the simulators so far available in the market mainly support simulation steps over 50 μs, while large step simulation may result in the action delay of pulse-width modulating (PWM), numerical oscillation and high-level non-characteristic harmonic distortion. In view of these problems, this paper puts forward a modeling method based on integral prediction and interpolation compensation. First of all, prediction is performed one step in advance by the implicit trapezoidal method to find out the accurate time when the triangle carrier wave intersects with the modulation wave. At the same time, a mathematic model is built for the insulated gate bipolar transistor (IGBT) to output equivalent voltage waveform according to the principle of area equivalent. Next, in MATLAB/Simulink, offline simulation is performed with the three-phase AC-DC-AC converter as the subject. By comparing the control accuracy, the content of harmonic wave and the simulation time, the simulation effects of the 50 μs fixed-step interpolation prediction model are the same as that for a 5 μs fixed-step standard model. Finally, the effectiveness and high efficiency of this algorithm are verified on a real-time simulator, marking the application of offline models on real-time simulators. Full article

(This article belongs to the Special Issue Advanced Perspectives for Modeling, Simulation and Control of Power Electronic Systems)

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