55 research outputs found

    Design and Advanced Model Predictive Control of Wide Bandgap Based Power Converters

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    The field of power electronics (PE) is experiencing a revolution by harnessing the superior technical characteristics of wide-band gap (WBG) materials, namely Silicone Carbide (SiC) and Gallium Nitride (GaN). Semiconductor devices devised using WBG materials enable high temperature operation at reduced footprint, offer higher blocking voltages, and operate at much higher switching frequencies compared to conventional Silicon (Si) based counterpart. These characteristics are highly desirable as they allow converter designs for challenging applications such as more-electric-aircraft (MEA), electric vehicle (EV) power train, and the like. This dissertation presents designs of a WBG based power converters for a 1 MW, 1 MHz ultra-fast offboard EV charger, and 250 kW integrated modular motor drive (IMMD) for a MEA application. The goal of these designs is to demonstrate the superior power density and efficiency that are achievable by leveraging the power of SiC and GaN semiconductors. Ultra-fast EV charging is expected to alleviate the challenge of range anxiety , which is currently hindering the mass adoption of EVs in automotive market. The power converter design presented in the dissertation utilizes SiC MOSFETs embedded in a topology that is a modification of the conventional three-level (3L) active neutral-point clamped (ANPC) converter. A novel phase-shifted modulation scheme presented alongside the design allows converter operation at switching frequency of 1 MHz, thereby miniaturizing the grid-side filter to enhance the power density. IMMDs combine the power electronic drive and the electric machine into a single unit, and thus is an efficient solution to realize the electrification of aircraft. The IMMD design presented in the dissertation uses GaN devices embedded in a stacked modular full-bridge converter topology to individually drive each of the motor coils. Various issues and solutions, pertaining to paralleling of GaN devices to meet the high current requirements are also addressed in the thesis. Experimental prototypes of the SiC ultra-fast EV charger and GaN IMMD were built, and the results confirm the efficacy of the proposed designs. Model predictive control (MPC) is a nonlinear control technique that has been widely investigated for various power electronic applications in the past decade. MPC exploits the discrete nature of power converters to make control decisions using a cost function. The controller offers various advantages over, e.g., linear PI controllers in terms of fast dynamic response, identical performance at a reduced switching frequency, and ease of applicability to MIMO applications. This dissertation also investigates MPC for key power electronic applications, such as, grid-tied VSC with an LCL filter and multilevel VSI with an LC filter. By implementing high performance MPC controllers on WBG based power converters, it is possible to formulate designs capable of fast dynamic tracking, high power operation at reduced THD, and increased power density

    Three-Port Bi-Directional DC–DC Converter with Solar PV System Fed BLDC Motor Drive Using FPGA

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    The increased need for renewable energy systems to generate power, store energy, and connect energy storage devices with applications has become a major challenge. Energy storage using batteries is most appropriate for energy sources like solar, wind, etc. A non-isolated three-port DC–DC-converter energy conversion unit is implemented feeding the brushless DCmotor drive. In this paper, a non-isolated three-port converter is designed and simulated for battery energy storage, interfaced with an output drive. Based on the requirements, the power extracted from the solar panel during the daytime is used to charge the batteries through the three-port converter. The proposed three-port converter is analyzed in terms of operating principles and power flow. An FPGA-based NI LabView PXI with SbRio interface is used to develop the suggested approach’s control hardware, and prototype model results are obtained to test the proposed three-port converter control system’s effectiveness and practicality. The overall efficiency of the converter’s output improves as a result. The success rate is 96.5 percent while charging an ESS, 98.1 percent when discharging an ESS, and 95.7 percent overall

    Modelling, Monitoring, Control and Optimization for Complex Industrial Processes

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    This reprint includes 22 research papers and an editorial, collected from the Special Issue "Modelling, Monitoring, Control and Optimization for Complex Industrial Processes", highlighting recent research advances and emerging research directions in complex industrial processes. This reprint aims to promote the research field and benefit the readers from both academic communities and industrial sectors

    Multi-busbar sub-module modular multilevel converter

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    Modular multilevel converter (MMC) plays increasingly significant roles in large scale power electronics system including high voltage direct current (HVDC) system, static synchronous compensator (STATCOM), large scale energy storage, motor control, and so on, thanks to its advantages including modular configurations, reduced dv/dt, low total harmonic distortions, and low power losses. The classic sub-module (SM) topologies (e.g. half or full bridge types) all have in common their single connection arrangement between each SM in their series connection within a stack; i.e. a single busbar. This single busbar arrangement does come however with some drawbacks in terms of performance, reliability and flexibility. The lack of redundant switching states limits the potential optimization for the whole MMC. To solve the above mentioned issue, this thesis presents the control and performance of a new topology of SMs for MMCs, which uses multiple parallel connections between SMs and is referred to as multi-busbar sub-module (MBSM). Stacks made entirely of MBSMs can see improved functionalities such as pre-charging capability, capacitor paralleling, lower power losses, improved reliability, and a rational bypass mechanism in the event of SM failure. The soft-parallel mechanism is proposed to maintain voltage balancing without the requirement of additional spike current inductors. Despite the fact that the number of semiconductors in MBSM MMC has been doubled, semiconductor losses have been reduced to 80% of those in its counterpart. Simulation results have verified the characteristics of a FB MBSM MMC in an HVDC scenario. Several advanced control schemes for the control of the MBSM MMC are also investigated, including an algorithm to automatically generate independent variables state space models from linear electrical circuits, a model predictive control-based start-up controller to simplify the SM pre-charge procedure and at the same time improve the transient performance, and a reinforcement learningbased low-level controller to achieve low switching frequency operation of the MBSM MMC. The control schemes are validated by detailed theoretical analysis and simulation results. Besides, some MBSM applications in the operation scenarios of STATCOM are studied. Two topologies of delta-configured, partially rated energy storage (PRES) MBSM STATCOM and their corresponding low-level controllers are presented to improve the active power output capability. The soft parallel of MBSM is more effective in reactive power mode than active power mode due to the location of ES, which sees their current circulation limited to their own SM capacitor. The proposed controller for the MBSM STATCOM dynamically switches between two operation modes to reduce the converter losses over the extended range of active power. Simulation results confirm the earlier point, in that PRES-MBSMSTATCOM performs better at pure reactive power set-points and marginally better at high active power. This is explained by the fact that MBSM operates more frequently in soft-paralleling mode when the ES releases less power, i.e. reactive power set-points. Then the MBSM concept is further extended to a structure with more busbars, named multi-H-bridge SM, aiming at solving the current sharing issue of paralleled discrete SiC MOSFETs in large current applications. When compared to conventional FBSM constructed directly paralleled SiC MOSFETs, simulation results show that the current sharing performance against on-state resistance mismatch is improved and the switching loss is reduced. The same converter rating can be achieved with fewer MHSMs compared with Si IGBT SMs. Finally, the designing process of a benchtop-scale, low-voltage, open-source, and affordable hardware prototype of a MMC, the ÎŒMMC, is presented with a case study of a three-phase inverter-mode MMC. The proposed ÎŒMMC is configured as full bridge SMs type in the experiment, yet the flexible structure makes it capable to be configured as other SM types, including MBSMs. The cost for a single ÎŒMMC could be around 50 pounds. The control framework and concrete implementation are presented in detail. With the application of the ÎŒMMC, the STM32Cube Hardware Abstraction Layer, and the MATLAB/Simulink hardware support packages, it is possible to shorten the transition process from simulation to hardware realization to several hours. The experiment setup and results of a three-phase inverter mode MMC validate the proposed ÎŒMMC’s effectiveness, scalability, and convenience

    Advanced Modeling and Research in Hybrid Microgrid Control and Optimization

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    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

    Refined Battery Energy Storage System Modelling for Grid Dispatch

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    Battery energy storage systems (BESSs) can be charged and discharged rapidly, which makes them capable of many tasks in the grid operation, such as frequency regulation and load management. However, BESSs generally suffer from high cost, not only from the initial investment but more importantly from the cycle loss and calendar loss due to unavoidable battery degradation. If the dispatchers do not follow suitable BESS operation plans, it may cause economic losses. Therefore, the BESS degradation models are important research topics by considering the BESS economic loss in the optimization problems. The research topic of this graduation thesis is to maximize the benefits that the BESSs bring when participating in power grid work. The following points need to be addressed to complete the topic: 1. it is valuable to identify the main degradation factors of Li-ion batteries when the BESSs are used in the power grid dispatching problems. 2. accurate and appropriate modeling of BESSs with other devices in the simulations and calculations. 3. the BESSs can be used in various power system tasks such as regulations services, reserve, OPF and contingency recovery, etc. Therefore, it is crucial to be clear how BESSs can be used in various scenarios. 4. the Li-ion battery life assessment methods can be used as the reference for measuring the accuracy of the BESS models. Therefore, it is necessary to adopt a suitable life span assessment method for the BESSs. The following work has been done in this thesis: 1. A C-rate-based BESS linearization model is established, which can consider the change of BESS control strategies and is suitable to be used in BESS high-power scenarios. The traditional BESS models are mainly based on the DoD and are designed for low-power working conditions. The proposed C-rate-based model makes up for the vacancy of traditional models in applicable scenarios. 2. A fatigue life cycle counting method is designed. This algorithm is used for BESS life evaluation. The proposed SCCM is better than the commonly used RCM for battery cycle life assessment. 3. The author carries out linearization processing according to the SCCM, establishing a SoC-DoD-based BESS model, which separately considers the fact that the charging and discharging of Li-ion batteries have different effects on cycle life. The optimization results show that the proposed model can obtain optimization results closer to the actual optimal situation

    Microgrids/Nanogrids Implementation, Planning, and Operation

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    Today’s power system is facing the challenges of increasing global demand for electricity, high-reliability requirements, the need for clean energy and environmental protection, and planning restrictions. To move towards a green and smart electric power system, centralized generation facilities are being transformed into smaller and more distributed ones. As a result, the microgrid concept is emerging, where a microgrid can operate as a single controllable system and can be viewed as a group of distributed energy loads and resources, which can include many renewable energy sources and energy storage systems. The energy management of a large number of distributed energy resources is required for the reliable operation of the microgrid. Microgrids and nanogrids can allow for better integration of distributed energy storage capacity and renewable energy sources into the power grid, therefore increasing its efficiency and resilience to natural and technical disruptive events. Microgrid networking with optimal energy management will lead to a sort of smart grid with numerous benefits such as reduced cost and enhanced reliability and resiliency. They include small-scale renewable energy harvesters and fixed energy storage units typically installed in commercial and residential buildings. In this challenging context, the objective of this book is to address and disseminate state-of-the-art research and development results on the implementation, planning, and operation of microgrids/nanogrids, where energy management is one of the core issues

    Data Mining Applications to Fault Diagnosis in Power Electronic Systems: A Systematic Review

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    Optimisation, Optimal Control and Nonlinear Dynamics in Electrical Power, Energy Storage and Renewable Energy Systems

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    The electrical power system is undergoing a revolution enabled by advances in telecommunications, computer hardware and software, measurement, metering systems, IoT, and power electronics. Furthermore, the increasing integration of intermittent renewable energy sources, energy storage devices, and electric vehicles and the drive for energy efficiency have pushed power systems to modernise and adopt new technologies. The resulting smart grid is characterised, in part, by a bi-directional flow of energy and information. The evolution of the power grid, as well as its interconnection with energy storage systems and renewable energy sources, has created new opportunities for optimising not only their techno-economic aspects at the planning stages but also their control and operation. However, new challenges emerge in the optimization of these systems due to their complexity and nonlinear dynamic behaviour as well as the uncertainties involved.This volume is a selection of 20 papers carefully made by the editors from the MDPI topic “Optimisation, Optimal Control and Nonlinear Dynamics in Electrical Power, Energy Storage and Renewable Energy Systems”, which was closed in April 2022. The selected papers address the above challenges and exemplify the significant benefits that optimisation and nonlinear control techniques can bring to modern power and energy systems

    Méthodes scalables de commande par allocation pour le convertisseur modulaire multiniveaux : de la modélisation à l'implémentation temps réel

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    Dans le cadre de la montĂ©e en puissance des convertisseurs statiques, les diffĂ©rents avantages qu’il y a Ă  utiliser les Convertisseurs Modulaires Multiniveaux (MMC) ont menĂ© Ă  leur popularisation. Cependant, Ă  mesure que le nombre de niveaux de tension et le nombre de phase augmentent, ces convertisseurs prĂ©sentent un nombre de plus en plus important de degrĂ©s de libertĂ© pour en effectuer la commande. Ainsi les MMC reprĂ©sentent un dĂ©fi pour la commande car le nombre de variables de commande est alors supĂ©rieur aux contraintes Ă  satisfaire, faisant d’eux des systĂšmes redondants ou encore sous-dĂ©terminĂ©s ce qui ouvre la voie de l’optimisation. D’abord apparues dans les annĂ©es 1980 dans l’aĂ©ronautique pour tirer profit de la multiplicitĂ© des surfaces aĂ©rodynamiques et des redondances associĂ©es que prĂ©sente un avion afin d’en contrĂŽler sa trajectoire (volets, ailerons, gouvernes
), les mĂ©thodes de commande par allocation ont fait leurs preuves en Ă©tant progressivement appliquĂ©es dans diffĂ©rents domaines technologiques. En parallĂšle ces algorithmes ont fait l’objet de travaux pour amĂ©liorer les performances obtenues et notamment s’adapter aux systĂšmes commandĂ©s. Le sujet de la thĂšse concerne donc le dĂ©veloppement et l’implĂ©mentation en temps rĂ©el de mĂ©thodes de commande par allocation, avec un souci d’optimisation en ligne, pour un systĂšme de conversion d’énergie Ă  base de MMC. La premiĂšre partie de la thĂšse portent sur la modĂ©lisation du convertisseur MMC en vue de sa commande Ă  partir de mĂ©thodes d’allocation. Ce qui implique le dĂ©veloppement de diffĂ©rents modĂšles de commande avec diffĂ©rents niveaux de dĂ©tails et de complexitĂ©. Un rĂ©sultat fort issu de cette premiĂšre partie est un modĂšle de commande dont la complexitĂ© n’est plus influencĂ©e par le nombre de phases du systĂšme Ă©lectrique considĂ©rĂ©. La deuxiĂšme Ă©tape des travaux concerne le dĂ©veloppement d’une nouvelle mĂ©thode d’allocation qui met Ă  profit les avantages des mĂ©thodes prĂ©sentes dans l’état de l’art pour en concevoir une nouvelle plus adaptĂ©e. Ainsi cette dĂ©marche a conduit Ă  la programmation d’un nouvel algorithme d’allocation prĂ©sentant des caractĂ©ristiques dynamiques et statiques rĂ©glables et adaptables simplement, son intĂ©gration aux mĂ©thodes dĂ©jĂ  existantes est aisĂ©e et presque immĂ©diat. La troisiĂšme Ă©tape des travaux combine les travaux prĂ©cĂ©dents. Tout d’abord en simulation, la mĂ©thode de commande par allocation du convertisseur est programmĂ©e puis testĂ©e pour finalement ĂȘtre validĂ©e. Pour la commande diffĂ©rentes architectures sont conçues permettant de rĂ©aliser des comparatifs afin d’évaluer leur capacitĂ© Ă  atteindre les performances requises pour le bon fonctionnement du systĂšme. Il en dĂ©coule une analyse des diffĂ©rents algorithmes de commande proposĂ©s. Le rĂ©sultat principal de cette partie est la conception d’un nouvel algorithme d’allocation permettant de contrĂŽler les tensions aux bornes des condensateurs ainsi que les tous les courants du convertisseur dans chacune des branches et ce indĂ©pendamment du nombre de phases. La quatriĂšme Ă©tape porte sur la validation expĂ©rimentale des mĂ©thodes dĂ©veloppĂ©es. Pour se faire, le convertisseur MMC disponible au laboratoire LAPLACE est utilisĂ© ainsi qu’un ensemble d’outils de prototypage rapide (OPAL-RT) permettant de tester et mettre au point les algorithmes de façon sĂ»re et efficace. La cinquiĂšme partie des travaux concerne l’extension, hors de la zone de fonctionnement nominale du convertisseur, des algorithmes de commande dĂ©veloppĂ©s. En effet une ouverture est proposĂ©e mettant en exergue les capacitĂ©s des mĂ©thodes d’allocation Ă  reconfigurer le fonctionnement du MMC lorsqu’un dĂ©faut apparait dans l’un des sous-modules. Les rĂ©sultats obtenus en simulation montrent une amĂ©lioration de la disponibilitĂ© du convertisseur, c’est-Ă -dire une continuitĂ© de fonctionnement en prĂ©sence de dĂ©fauts ce qui justifie l’intĂ©rĂȘt de poursuivre les travaux dans cette direction
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