134 research outputs found

    Decentralised sliding mode control for nonlinear interconnected systems with uncertainties

    Get PDF
    With the advances in science and technology, nonlinear large-scale interconnected systems have widely appeared in the real life. Traditional centralised control methods have inevitable disadvantages when they are used to deal with complex nonlinear interconnected systems with uncertainties. In connection with this, people desire to develop the novel control strategy which can be applied to complex interconnected systems. Therefore, decentralised sliding mode control (SMC) for interconnected systems has attracted great attention in related fields due to its advantages, for instance, simple structure, low cost of calculation, fast response, reduced-order sliding mode dynamics and insensitivity to matched variation of parameters and disturbances in systems. This thesis focuses on the development of decentralised SMC for nonlinear interconnected systems with uncertainties under certain assumptions. Several methods and different techniques have been considered in design of the controller to improve the robustness. The main contributions of this thesis include: • The state feedback decentralised SMC is developed for nonlinear interconnected systems with matched uncertainty and mismatched unknown interconnections. A state feedback decentralised SMC strategy, under the assumption that all system states are accessible, is proposed to attenuate the impact of the uncertainties by using bounds on uncertainties and interconnections. The bounds used in the design are fully nonlinear which provide higher applicability for different complex interconnected systems. Especially, for this fully nonlinear system, the proposed method does not need to use the technique of linearisation, which is widely used in existing work to deal with nonlinear interconnected systems with uncertainties. • The dynamic observer is applied to complex nonlinear interconnected systems with matched and mismatched uncertainties. This dynamic observer can estimate the system states which can not be achieved during the controller design. The proposed method has great identification ability with small estimated errors for the states of nonlinear interconnected systems with matched and mismatched uncertainties. It should be pointed out that the considered uncertainties of nonlinear interconnected systems have general forms, which means that the proposed method can be effectively used in more generalised nonlinear interconnected systems. • A variable structure observer-based decentralised SMC is proposed to control a class of nonlinear interconnected systems with matched and mismatched uncertainties. Based on the designed dynamic observer, a dynamic decentralised output feedback SMC using outputs and estimated states is presented to control the interconnected systems with matched and mismatched uncertainties. The nonlinear interconnections are employed in the control design to reduce the conservatism of the developed results. The bounds of the uncertainties are relaxed which are nonlinear and take more general forms. Moreover, the limitation for the interconnected system is reduced when compared with the existing results in which the proposed strategies adopt the full-order observer. Besides that, the presented method improves the robustness of nonlinear interconnected systems to be against the effects of uncertainties. This thesis also provides several numerical and practical simulations to demonstrate the effectiveness of the proposed decentralised SMC for nonlinear interconnected systems with matched uncertainty, mismatched uncertainty and nonlinear interconnections

    Efficiency and Sustainability of the Distributed Renewable Hybrid Power Systems Based on the Energy Internet, Blockchain Technology and Smart Contracts-Volume II

    Get PDF
    The climate changes that are becoming visible today are a challenge for the global research community. In this context, renewable energy sources, fuel cell systems, and other energy generating sources must be optimally combined and connected to the grid system using advanced energy transaction methods. As this reprint presents the latest solutions in the implementation of fuel cell and renewable energy in mobile and stationary applications, such as hybrid and microgrid power systems based on the Energy Internet, Blockchain technology, and smart contracts, we hope that they will be of interest to readers working in the related fields mentioned above

    Nonlinear Systems

    Get PDF
    Open Mathematics is a challenging notion for theoretical modeling, technical analysis, and numerical simulation in physics and mathematics, as well as in many other fields, as highly correlated nonlinear phenomena, evolving over a large range of time scales and length scales, control the underlying systems and processes in their spatiotemporal evolution. Indeed, available data, be they physical, biological, or financial, and technologically complex systems and stochastic systems, such as mechanical or electronic devices, can be managed from the same conceptual approach, both analytically and through computer simulation, using effective nonlinear dynamics methods. The aim of this Special Issue is to highlight papers that show the dynamics, control, optimization and applications of nonlinear systems. This has recently become an increasingly popular subject, with impressive growth concerning applications in engineering, economics, biology, and medicine, and can be considered a veritable contribution to the literature. Original papers relating to the objective presented above are especially welcome subjects. Potential topics include, but are not limited to: Stability analysis of discrete and continuous dynamical systems; Nonlinear dynamics in biological complex systems; Stability and stabilization of stochastic systems; Mathematical models in statistics and probability; Synchronization of oscillators and chaotic systems; Optimization methods of complex systems; Reliability modeling and system optimization; Computation and control over networked systems

    Genetic algorithm optimized robust nonlinear observer for a wind turbine system based on permanent magnet synchronous generator

    Get PDF
    © 2022 ISA. Published by Elsevier Ltd. All rights reserved. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1016/j.isatra.2022.02.004This paper presents an optimal control scheme for a Permanent Magnet Synchronous Generator (PMSG) coupled to a wind turbine operating without a position sensor. This sensorless scheme includes two observers: The first observer uses the flux to estimate the speed. However, an increase in the temperature or a degradation of the permanent magnet characteristics will result in a demagnetization of the machine causing a drop in the flux. The second observer is therefore used to estimate these changes in the flux from the speed and guaranties the stability of the system. This structure leads to a better exchange of information between the two observers, eliminates the problem of encoder and compensates for the demagnetization problem. To improve the precision of the speed estimator, the gain of the non-linear observer is optimized using Genetic Algorithm (GA) and the speed is obtained from a modified Phase Locked Loop (PLL) method using an optimized Sliding Mode Controller (SMC). Furthermore, to enhance the convergence speed of this observer scheme and improve the performance of the system a Fast Super Twisting Sliding Mode Control (FSTSMC) is introduced to reinforce the SMC strategy. A series of simulations are presented to show the effectiveness and robustness of proposed observer scheme.Peer reviewe

    Artificial Intelligence Supported EV Electric Powertrain for Safety Improvement

    Get PDF
    As an environmentally friendly transport option, electric vehicles (EVs) are endowed with the characteristics of low fossil energy consumption and low pollutant emissions. In today's growing market share of EVs, the safety and reliability of the powertrain system will be directly related to the safety of human life. Reliability problems of EV powertrains may occur in any power electronic (PE) component and mechanical part, both sudden and cumulative. These faults in different locations and degrees will continuously threaten the life of drivers and pedestrians, bringing irreparable consequences. Therefore, monitoring and predicting the real-time health status of EV powertrain is a high-priority, arduous and challenging task. The purposes of this study are to develop AI-supported effective safety improvement techniques for EV powertrains. In the first place, a literature review is carried out to illustrate the up-to-date AI applications for solving condition monitoring and fault detection issues of EV powertrains, where recent case studies between conventional methods and AI-based methods in EV applications are compared and analysed. On this ground this study, then, focuses on the theories and techniques concerning this topic so as to tackle different challenges encountered in the actual applications. In detail, first, as for diagnosing the bearing system in the earlier fault period, a novel inferable deep distilled attention network is designed to detect multiple bearing faults. Second, a deep learning and simulation driven approach that combines the domain-adversarial neural network and the lumped-parameter thermal network (LPTN) is proposed for achieve IPMSM permanent magnet temperature estimation work. Finally, to ensure the use safety of the IGBT module, deep learning -based IGBT modules’ double pulse test (DPT) efficiency enhancement is proposed and achieved via multimodal fusion networks and graph convolution networks

    Beiträge zur Regelung elektrischer Maschinen an Mehrpunktstromrichtern unter Nutzung optimierter Pulsmuster

    Get PDF
    Diese Arbeit beschäftigt sich der Modulation und Regelung von Mehrpunktstromrichtern zum Antrieb elektrischer Maschinen unter Nutzung optimierter Pulsmuster. Ziel der Arbeit ist es, das Potential und die Grenzen der Modulation mit optimierten Pulsmustern unter der Randbedingung der heute vorhandenen Softwareframeworks und Rechentechnik aufzuzeigen. Darüber hinaus soll dem Leser ein gesamtheitlicher Überblick über die optimierten Pulsmuster vermittelt werden. Ausgehend vom Stand der Technik der verbreiteten Arten der Modulation werden die optimierten Pulsmuster eingeführt. Für die notwendige Berechnung der Pulsmuster als Lösung einer Optimierungsaufgabe wird ein allgemeines Konzept der mathematischen Beschreibung vorgestellt. Darauf basierend werden zehn heute verfügbare numerische Löser auf ihre Konvergenz bezüglich der Lösung des gestellten Problems untersucht. Die Ergebnisse zeigen, dass es möglich ist, optimierte Pulsmuster mit Frequenzverhältnissen mf ≤ 21 online zu berechnen und dass geeignete Löser auch bei mf ≫ 50 sicher konvergieren. Eine Analyse der gefundenen Lösungen zeigt, dass der von trägerbasierten Modulationen bekannte lineare Zusammenhang zwischen mittlerer Schaltfrequenz und Schaltverlusten bei den optimierten Pulsmustern nicht gegeben ist. Darauf aufbauend wird ein neuer Algorithmus zur Wahl verlustminimierter Pulsmuster erarbeitet. Es zeigt sich, dass dessen Einsatz auch bei mf ≫ 21 gegenüber der Raumzeigermodulation zu einer signifikanten Reduktion der Schaltverluste (ca. 20%) führt. Mit den Grundlagen der Berechnung und der Analyse der Eigenschaften der optimierten Pulsmuster, wird basierend auf dem Stand der Technik ein neuartiger lastunabhängiger Modulator entwickelt. Dieser kompensiert die Unstetigkeiten der Pulsmusterwechsel durch Regelung des Integrals des harmonischen Inhalts der Pulsmuster. Aufbauend auf diesem neuartigen Modulator wird eine parameterrobuste Maschinenregelung entworfen. Diese weist eine Dead-Beat-Dynamik der Regelung des elektrischen Momentes einer angeschlossenen Maschine auf und ermöglicht im stationären Zustand, im Gegensatz zu den bestehenden Konzepten, die Ausgabe eines unveränderten Pulsmusters. Damit wird die angestrebte minimierte Stromwelligkeit erreicht. Im letzten Teil der Arbeit wird der Einfluss einer Modulation mit optimierten Pulsmustern auf den Symmetrierungsvorgang eines selbstgeführten Dreipunkt-UStromrichter (3L-NPC-VSC) untersucht. Dabei wird eine neue Methode der Reduktion der dynamischen Zwischenkreiswelligkeit, sowie eine neuartige, in allen Arbeitspunkten stabile, Methode der statischen Zwischenkreissymmetrierung präsentiert. Alle erarbeiteten Algorithmen wurden mit Hilfe von Simulationen und Experimenten verifiziert.:1 Einleitung 1 1.1 Inhalt und Motivation der vorliegenden Arbeit 2 1.2 Experimenteller Versuchsstand 4 1.3 Verwendete Grundlagen und Kennwerte 6 1.3.1 Fourieranalyse 6 1.3.2 Laplace-Transformation 7 1.3.3 Gütekriterien 8 2 Modulation 9 2.1 Klassifikation der Generierung der Pulsmuster 9 2.2 Modulationsverfahren 11 2.2.1 Trägerbasierte Pulsweitenmodulation 11 2.2.2 Raumzeigermodulation 22 2.2.3 Optimierte Pulsmuster 25 3 Optimierte Pulsmuster 29 3.1 Optimierungskriterien 30 3.1.1 Gewichtetes Gesamt-Oberschwingungsverhältnis 30 3.1.2 Gesamt-Oberschwingungsverhältnis 30 3.1.3 Minimale Drehmomentwelligkeit 31 3.1.4 Individuelle Wichtung der Harmonischen 32 3.1.5 Verlustminimierung in der Last 33 3.1.6 Schaltverlustminimierung der Halbleiter des Umrichters 34 3.2 Formulierung der Optimierungsaufgabe der optimierten Pulsmuster 35 3.2.1 Berechnung der Fourierkoeffizienten 36 3.2.2 Notwendige Nebenbedingungen der Optimierung 38 3.3 Vergleich von Algorithmen der nichtlinearen Optimierung 38 3.3.1 Vergleich verschiedener Lösungsmethoden 39 3.3.2 Definition des für den Vergleich genutzten Problems 43 3.3.3 Dauer der Berechnung der lokalen Minima 44 3.3.4 Vergleich der lokalen Minima der verschiedenen Löser 45 3.3.5 Berechnung verlustminimaler optimierter Pulsmuster 46 3.3.6 Untersuchungen zur Auswahl der lokalen Minima 47 3.3.7 Vergleich der optimierten Pulsmuster mit SVM und CB-Modulation 56 4 Stand der Technik der Regelung von Drehstrommaschinen 60 4.1 Grundlagen der Modellierung der Asynchronmaschine 60 4.2 Klassische Ansätze der Regelung elektrischer Maschinen 62 4.2.1 Feldorientierte Regelung 62 4.2.2 Direkte Selbstregelung 69 4.2.3 Direkte Momentenregelung 72 4.2.4 Vergleich der vorgestellten klassischen Regelungsarten 75 4.3 Regelung mit optimierten Pulsmustern auf Basis der Feldorientierung 76 4.3.1 Dynamischer Modulationsfehler durch unstetige Pulsmuster 76 4.3.2 Direkte Pulsmustermodifikation 80 4.3.3 Behandlung des dynamischen Modulationsfehlers 84 4.4 Geschlossener Regelkreis 86 4.5 Regelung mit optimierten Pulsmustern auf Basis der DSC 92 4.5.1 Eigenschaften der vorgestellten Pulserzeugungsarten 94 4.5.2 Dynamischen Eigenschaften der vorgestellten Regelungsstrukturen 95 5 Verallgemeinerte Konzepte zur Nutzung optimierter Pulsmuster 98 5.1 Implementierung eines allgemeingültigen OPP-Modulators 98 5.2 Behandlung des harmonischen Anteils der Pulsmuster 104 5.3 Modulation und Modifikation der Pulsmuster bei hohem mf 105 5.4 Dead-Beat-Control auf Basis der Pulsmustermodifikation 108 5.5 Maschinen-Beobachter 109 5.5.1 Beobachter der Asynchronmaschine 111 5.5.2 Beobachter der permanenterregten Synchronmaschine 114 5.6 Geschlossener Statorflussregelkreis 115 5.6.1 Untersuchung der Sensitivität des Modells 119 5.7 Entwurf der übergeordneten Regelkreise 123 5.7.1 Entwurf des Rotorflussreglers 125 5.7.2 Entwurf des Drehzahlreglers 126 5.7.3 Begrenzung des Statorstromes 127 5.7.4 Simulative und experimentelle Ergebnisse 127 6 Zwischenkreissymmetrierung des 3L-NPC-VSC bei OPP-Modulation 135 6.1 Der Neutralpunktstrom 135 6.2 Minimierung der Neutralpunktstromwelligkeit 138 6.3 Aktive Symmetrierung 140 6.4 Integration der Regelung der Zwischenkreissymmetrie 154 7 Zusammenfassung 158 Literatur 161 Abkürzungsverzeichnis 177 Symbolverzeichnis 178This thesis deals with the modulation and control of multilevel converters as electrical drives using an optimized pulse pattern (OPP) modulation scheme. The aim of the work is to determine the potential and the limits of the modulation using OPPs, considering state-of-the-art software frameworks und computing technology. Furthermore the reader shell get a holistic overview of all aspects regarding the use of OPPs. Starting with the state-of-the-art of the most popular modulation schemes and their characteristics the optimized pulse patterns are introduced. A general mathematical formulation, which describes the OPP calculation as minimization problem, is shown. With this formulation, ten implementations of nonlinear constraint minimization algorithms are analyzed with regard to the convergence behavior. It is shown, that OPP can be calculated online for frequency ratios mf ≫ 21. Further, some algorithms converge reliable also for mf ≫ 50. Afterwards, the solutions of the minimization of the weighted total harmonic distortion (WTHD) problem are analyzed. It is shown, that the linear relationship between the averaged switching frequency and the switching loss, which is known from carrier based modulation schemes, does not apply for OPPs. A new method to find loss optimized pulse patterns is proposed. With this method the modulation using OPPs can reduce the converter switching losses in comparison to space vector modulation significantly (20%) also for mf ≫ 21. Based on the analysis of the found OPP solutions a novel modulator, which is independent of the parameters of the load, is proposed. This modulator compensates the discontinuities due to the pulse pattern changes by controlling the integral of the harmonic content of the modulator output. Based on this modulator a new parameter robust machine control was developed. This concept shows a dead-beat-dynamic of the control of the electrical torque and uses in contrast to state-of-the-art concepts the unmodified OPP in steady state, which leads to a minimal load current ripple. The last part of the thesis deals with the influence of using an OPP modulation on the DC-link balancing of a Three-Level Neutral-Point-Clamped Voltage-Source-Converter (3L-NPC-VSC). A new method to reduce the dynamic neutral-pointpotential-ripple as well as a new stable static balancing method are proposed. All proposed algorithms and methods are verified by simulation and experiment.:1 Einleitung 1 1.1 Inhalt und Motivation der vorliegenden Arbeit 2 1.2 Experimenteller Versuchsstand 4 1.3 Verwendete Grundlagen und Kennwerte 6 1.3.1 Fourieranalyse 6 1.3.2 Laplace-Transformation 7 1.3.3 Gütekriterien 8 2 Modulation 9 2.1 Klassifikation der Generierung der Pulsmuster 9 2.2 Modulationsverfahren 11 2.2.1 Trägerbasierte Pulsweitenmodulation 11 2.2.2 Raumzeigermodulation 22 2.2.3 Optimierte Pulsmuster 25 3 Optimierte Pulsmuster 29 3.1 Optimierungskriterien 30 3.1.1 Gewichtetes Gesamt-Oberschwingungsverhältnis 30 3.1.2 Gesamt-Oberschwingungsverhältnis 30 3.1.3 Minimale Drehmomentwelligkeit 31 3.1.4 Individuelle Wichtung der Harmonischen 32 3.1.5 Verlustminimierung in der Last 33 3.1.6 Schaltverlustminimierung der Halbleiter des Umrichters 34 3.2 Formulierung der Optimierungsaufgabe der optimierten Pulsmuster 35 3.2.1 Berechnung der Fourierkoeffizienten 36 3.2.2 Notwendige Nebenbedingungen der Optimierung 38 3.3 Vergleich von Algorithmen der nichtlinearen Optimierung 38 3.3.1 Vergleich verschiedener Lösungsmethoden 39 3.3.2 Definition des für den Vergleich genutzten Problems 43 3.3.3 Dauer der Berechnung der lokalen Minima 44 3.3.4 Vergleich der lokalen Minima der verschiedenen Löser 45 3.3.5 Berechnung verlustminimaler optimierter Pulsmuster 46 3.3.6 Untersuchungen zur Auswahl der lokalen Minima 47 3.3.7 Vergleich der optimierten Pulsmuster mit SVM und CB-Modulation 56 4 Stand der Technik der Regelung von Drehstrommaschinen 60 4.1 Grundlagen der Modellierung der Asynchronmaschine 60 4.2 Klassische Ansätze der Regelung elektrischer Maschinen 62 4.2.1 Feldorientierte Regelung 62 4.2.2 Direkte Selbstregelung 69 4.2.3 Direkte Momentenregelung 72 4.2.4 Vergleich der vorgestellten klassischen Regelungsarten 75 4.3 Regelung mit optimierten Pulsmustern auf Basis der Feldorientierung 76 4.3.1 Dynamischer Modulationsfehler durch unstetige Pulsmuster 76 4.3.2 Direkte Pulsmustermodifikation 80 4.3.3 Behandlung des dynamischen Modulationsfehlers 84 4.4 Geschlossener Regelkreis 86 4.5 Regelung mit optimierten Pulsmustern auf Basis der DSC 92 4.5.1 Eigenschaften der vorgestellten Pulserzeugungsarten 94 4.5.2 Dynamischen Eigenschaften der vorgestellten Regelungsstrukturen 95 5 Verallgemeinerte Konzepte zur Nutzung optimierter Pulsmuster 98 5.1 Implementierung eines allgemeingültigen OPP-Modulators 98 5.2 Behandlung des harmonischen Anteils der Pulsmuster 104 5.3 Modulation und Modifikation der Pulsmuster bei hohem mf 105 5.4 Dead-Beat-Control auf Basis der Pulsmustermodifikation 108 5.5 Maschinen-Beobachter 109 5.5.1 Beobachter der Asynchronmaschine 111 5.5.2 Beobachter der permanenterregten Synchronmaschine 114 5.6 Geschlossener Statorflussregelkreis 115 5.6.1 Untersuchung der Sensitivität des Modells 119 5.7 Entwurf der übergeordneten Regelkreise 123 5.7.1 Entwurf des Rotorflussreglers 125 5.7.2 Entwurf des Drehzahlreglers 126 5.7.3 Begrenzung des Statorstromes 127 5.7.4 Simulative und experimentelle Ergebnisse 127 6 Zwischenkreissymmetrierung des 3L-NPC-VSC bei OPP-Modulation 135 6.1 Der Neutralpunktstrom 135 6.2 Minimierung der Neutralpunktstromwelligkeit 138 6.3 Aktive Symmetrierung 140 6.4 Integration der Regelung der Zwischenkreissymmetrie 154 7 Zusammenfassung 158 Literatur 161 Abkürzungsverzeichnis 177 Symbolverzeichnis 17

    Advanced Modeling and Research in Hybrid Microgrid Control and Optimization

    Get PDF
    This book presents the latest solutions in fuel cell (FC) and renewable energy implementation in mobile and stationary applications. The implementation of advanced energy management and optimization strategies are detailed for fuel cell and renewable microgrids, and for the multi-FC stack architecture of FC/electric vehicles to enhance the reliability of these systems and to reduce the costs related to energy production and maintenance. Cyber-security methods based on blockchain technology to increase the resilience of FC renewable hybrid microgrids are also presented. Therefore, this book is for all readers interested in these challenging directions of research

    Power Converter of Electric Machines, Renewable Energy Systems, and Transportation

    Get PDF
    Power converters and electric machines represent essential components in all fields of electrical engineering. In fact, we are heading towards a future where energy will be more and more electrical: electrical vehicles, electrical motors, renewables, storage systems are now widespread. The ongoing energy transition poses new challenges for interfacing and integrating different power systems. The constraints of space, weight, reliability, performance, and autonomy for the electric system have increased the attention of scientific research in order to find more and more appropriate technological solutions. In this context, power converters and electric machines assume a key role in enabling higher performance of electrical power conversion. Consequently, the design and control of power converters and electric machines shall be developed accordingly to the requirements of the specific application, thus leading to more specialized solutions, with the aim of enhancing the reliability, fault tolerance, and flexibility of the next generation power systems
    • …
    corecore