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Hybrid Lcc And Multi Terminal Full Bridge Modular Multilevel Converters For Hvdc Transmission
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Book Synopsis Hybrid LCC and Multi-terminal Full-bridge Modular Multilevel Converters for HVDC Transmission by : Udeesha Supundi Annakkage
Download or read book Hybrid LCC and Multi-terminal Full-bridge Modular Multilevel Converters for HVDC Transmission written by Udeesha Supundi Annakkage and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Design, Control, and Application of Modular Multilevel Converters for HVDC Transmission Systems by : Kamran Sharifabadi
Download or read book Design, Control, and Application of Modular Multilevel Converters for HVDC Transmission Systems written by Kamran Sharifabadi and published by John Wiley & Sons. This book was released on 2016-08-22 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt: Design, Control and Application of Modular Multilevel Converters for HVDC Transmission Systems is a comprehensive guide to semiconductor technologies applicable for MMC design, component sizing control, modulation, and application of the MMC technology for HVDC transmission. Separated into three distinct parts, the first offers an overview of MMC technology, including information on converter component sizing, Control and Communication, Protection and Fault Management, and Generic Modelling and Simulation. The second covers the applications of MMC in offshore WPP, including planning, technical and economic requirements and optimization options, fault management, dynamic and transient stability. Finally, the third chapter explores the applications of MMC in HVDC transmission and Multi Terminal configurations, including Supergrids. Key features: Unique coverage of the offshore application and optimization of MMC-HVDC schemes for the export of offshore wind energy to the mainland. Comprehensive explanation of MMC application in HVDC and MTDC transmission technology. Detailed description of MMC components, control and modulation, different modeling approaches, converter dynamics under steady-state and fault contingencies including application and housing of MMC in HVDC schemes for onshore and offshore. Analysis of DC fault detection and protection technologies, system studies required for the integration of HVDC terminals to offshore wind power plants, and commissioning procedures for onshore and offshore HVDC terminals. A set of self-explanatory simulation models for HVDC test cases is available to download from the companion website. This book provides essential reading for graduate students and researchers, as well as field engineers and professionals who require an in-depth understanding of MMC technology.
Book Synopsis Design, Analysis and Operation of Hybrid Modular Multilevel Converters for HVDC Applications by : Zeng Rong
Download or read book Design, Analysis and Operation of Hybrid Modular Multilevel Converters for HVDC Applications written by Zeng Rong and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis investigates the design, analysis, and operation of modular multilevel converters (MMC) for HVDC applications. Based on the operation principles of the MMC, the operation of MMC under asymmetrical arm impedance conditions is analysed using three equivalent sub-circuits at different freqeuncy. Detail analysis of the impact of asymmetrical conditions on the differential-mode current, the common-mode current and sub-module (SM) capacitor voltages, is performed. Based on the analysis, the corresponding control targets and an improved control strategy are designed to improve the operation performance. Considering the advantages of half-bridge based SM (HBSM) and full-bridge based SM (FBSM), a hybrid MMC (H-MMC) configuration consisting of FBSMs and HBSMs is proposed. By adopting the negative voltage state for some of the FBSMs, the output voltage range is extended to increase converter power transmission capability. By considering the relationships between the AC and DC voltages, AC, DC and arm currents, the ratio of the numbers of the FBSM to HBSM is analysed in order to maintain capacitor voltage balance and retain DC fault blocking capability. An equivalent circuit for the H-MMC is proposed, which considers each arm to be consisted of two individual voltage sources. This model is used to analyse SM capacitor voltage balancing and ripple. A two-stage selection and sorting algorithm is developed to ensure capacitor voltage balancing among the SMs. The proposed H-MMC is compared to other topologies in terms of power device utilization and power losses, and it shows that the H-MMC has higher device utilization and lower power loss than the conventional FBSM based MMC; Furthermore, The DC fault ride-through capability of the H-MMC are discussed. It is found that the H-MMC can not only isolate the DC fault, but also coniture operating at a wide DC voltage range from zero to rated value. Such two features of the H-MMC show the advantages in the hybrid configurations over the conventional FBSM and HBSM systems. Finally, two applications based on the proposed H-MMC are presented; one is a high power DC/DC converter with fault blocking capability for interconnecting large HVDC systems, and the other is a hybrid HVDC transmission system comprising a wind farm side VSC based on the H-MMC and a grid side LCC for transmitting wind power to AC grid.
Book Synopsis High Voltage Direct Current Transmission by : Dragan Jovcic
Download or read book High Voltage Direct Current Transmission written by Dragan Jovcic and published by John Wiley & Sons. This book was released on 2019-07-01 with total page 657 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presents the latest developments in switchgear and DC/DC converters for DC grids, and includes substantially expanded material on MMC HVDC This newly updated edition covers all HVDC transmission technologies including Line Commutated Converter (LCC) HVDC; Voltage Source Converter (VSC) HVDC, and the latest VSC HVDC based on Modular Multilevel Converters (MMC), as well as the principles of building DC transmission grids. Featuring new material throughout, High Voltage Direct Current Transmission: Converters, Systems and DC Grids, 2nd Edition offers several new chapters/sections including one on the newest MMC converters. It also provides extended coverage of switchgear, DC grid protection and DC/DC converters following the latest developments on the market and in research projects. All three HVDC technologies are studied in a wide range of topics, including: the basic converter operating principles; calculation of losses; system modelling, including dynamic modelling; system control; HVDC protection, including AC and DC fault studies; and integration with AC systems and fundamental frequency analysis. The text includes: A chapter dedicated to hybrid and mechanical DC circuit breakers Half bridge and full bridge MMC: modelling, control, start-up and fault management A chapter dedicated to unbalanced operation and control of MMC HVDC The advancement of protection methods for DC grids Wideband and high-order modeling of DC cables Novel treatment of topics not found in similar books, including SimPowerSystems models and examples for all HVDC topologies hosted by the 1st edition companion site. High Voltage Direct Current Transmission: Converters, Systems and DC Grids, 2nd Edition serves as an ideal textbook for a graduate-level course or a professional development course.
Book Synopsis Multi-terminal High-voltage Converter by : Bo Zhang
Download or read book Multi-terminal High-voltage Converter written by Bo Zhang and published by John Wiley & Sons. This book was released on 2018-10-19 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: An all-in-one guide to high-voltage, multi-terminal converters, this book brings together the state of the art and cutting-edge techniques in the various stages of designing and constructing a high-voltage converter. The book includes 9 chapters, and can be classified into three aspects. First, all existing high-voltage converters are introduced, including the conventional two-level converter, and the multi-level converters, such as the modular multi-level converter (MMC). Second, different kinds of multi-terminal high-voltage converters are presented in detail, including the topology, operation principle, control scheme and simulation verification. Third, some common issues of the proposed multi-terminal high-voltage converters are discussed, and different industrial applications of the proposed multi-terminal high-voltage converters are provided. Systematically proposes, for the first time, the design methodology for high-voltage converters in use of MTDC grids; also applicable to constructing novel power electronics converters, and driving the development of HVDC, which is one of the most important technology areas Presents the latest research on multi-terminal high-voltage converters and its application in MTDC transmission systems and other industrially important applications Offers an overview of existing technology and future trends of the high-voltage converter, with extensive discussion and analysis of different types of high-voltage converters and relevant control techniques (including DC-AC, AC-DC, DC-DC, and AC-AC converters) Provides readers with sufficient context to delve into the more specialized topics covered in the book Featuring a series of novel multi-terminal high-voltage converters proposed and patented by the authors, Multi-terminal High Voltage Converters is written for researchers, engineers, and advanced students specializing in power electronics, power system engineering and electrical engineering.
Book Synopsis Multilevel Voltage Source Converters in High Voltage Direct Current Transmission Systems by : Yushu Zhang
Download or read book Multilevel Voltage Source Converters in High Voltage Direct Current Transmission Systems written by Yushu Zhang and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research focuses on voltage source multilevel converters in high voltage direct current (HVDC) transmission systems. The first Voltage Source Converter based HVDC (VSC-HVDC) systems with series connected IGBTs in a two-level converter represented a solution to meet industrial and economical requirements but is associated with significant drawbacks such as high dv/dt and di/dt, high switching loss, and poor output voltage and current quality. To overcome these issues, the multilevel converter was proposed for HVDC application. The Modular Multilevel Converter (M2C) was the first multilevel converter to be commercially used in the power industry. In this thesis, the M2C is investigated mainly in terms of operating principle, capacitor size and capacitor voltage ripple, capacitor voltage balancing technique and modulation scheme. The results of this investigation show that the M2C offers the following features: improved efficiency, lower supporting voltage and current in the switching devices and low dv/dt. These features make the M2C suitable for HVDC systems. Two new operational principles and modulation strategies for a Hybrid Cascaded Multilevel Converter (HCMC) are proposed in this thesis. Both modulation schemes extend the modulation index linear range and improve the output waveform quality. This gives the HCMC a higher power density than any known multilevel converter topology for the same dc link voltage and switching device rating. Simulations for both types of multilevel converter (M2C and HCMC) are supported by practical results from scaled hardware laboratory converters. Mathematical analysis and calculation of conversion loss for both types of multilevel converter and for the conventional two-level converter are performed. It is shown that both M2C and HCMC provide lower conversion loss compare to the conventional two-level converter. A control strategy for these two multilevel converters in point-to-point and multi-terminal HVDC systems is also studied. Simulation results show that these two converters are able to operate over the entire specified P-Q capability curve and are capable of riding through ac faults without imposing any over-voltage or over-current on the converter switches.
Book Synopsis Modular Multilevel Converters by : Sixing Du
Download or read book Modular Multilevel Converters written by Sixing Du and published by John Wiley & Sons. This book was released on 2018-02-22 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt: An invaluable academic reference for the area of high-power converters, covering all the latest developments in the field High-power multilevel converters are well known in industry and academia as one of the preferred choices for efficient power conversion. Over the past decade, several power converters have been developed and commercialized in the form of standard and customized products that power a wide range of industrial applications. Currently, the modular multilevel converter is a fast-growing technology and has received wide acceptance from both industry and academia. Providing adequate technical background for graduate- and undergraduate-level teaching, this book includes a comprehensive analysis of the conventional and advanced modular multilevel converters employed in motor drives, HVDC systems, and power quality improvement. Modular Multilevel Converters: Analysis, Control, and Applications provides an overview of high-power converters, reference frame theory, classical control methods, pulse width modulation schemes, advanced model predictive control methods, modeling of ac drives, advanced drive control schemes, modeling and control of HVDC systems, active and reactive power control, power quality problems, reactive power, harmonics and unbalance compensation, modeling and control of static synchronous compensators (STATCOM) and unified power quality compensators. Furthermore, this book: Explores technical challenges, modeling, and control of various modular multilevel converters in a wide range of applications such as transformer and transformerless motor drives, high voltage direct current transmission systems, and power quality improvement Reflects the latest developments in high-power converters in medium-voltage motor drive systems Offers design guidance with tables, charts graphs, and MATLAB simulations Modular Multilevel Converters: Analysis, Control, and Applications is a valuable reference book for academic researchers, practicing engineers, and other professionals in the field of high power converters. It also serves well as a textbook for graduate-level students.
Book Synopsis Implementation of DC/DC Converters in Hybrid LCC-VSC HVDC Grids by : Josep Arévalo Soler
Download or read book Implementation of DC/DC Converters in Hybrid LCC-VSC HVDC Grids written by Josep Arévalo Soler and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This Master Thesis presents the modelling, control and simulation of a hybrid multi-terminal High Voltage Direct Current (HVDC) grid. This network is composed by two point-to-point lines linked by a DC/DC converter. One point-to-point line is based on Line-Commutated Converters (LCC) and the other one is based on Voltage Source Converters (VSC), modeled as Modular Multilevel Converters (MMC). These two technologies are the most used ones in HVDC. The DC/DC converters chosen to analyze the multi-terminal grid are the Front-to-Front MMC and the DC-MMC. In order to achieve the final multi-terminal HVDC grid, the basics of both HVDC technologies are studied. It also includes the modelling, control and simulation of two point-to-point lines. One for LCC technology and the other one for VSC technology. The principles of DC/DC converters are also studied, including the modelling and control of a Front-to-Front MMC converter and a DC-MMC converter. Finally, simulations of the multi-terminal grid are performed with Matlab Simulink in di↵erent scenarios, including four cases for each DC/DC converter. In these di↵erent cases the DC/DC converter is placed regulating the DC voltage or controlling the power flow in the di↵erent point-to-point links.
Book Synopsis Control of an H-bridge Modular Multilevel Converter for Reliable Operation of DC Transmission Systems by : Chao Chen
Download or read book Control of an H-bridge Modular Multilevel Converter for Reliable Operation of DC Transmission Systems written by Chao Chen and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents improved modulation and control schemes for an H-bridge modular multilevel converter (MMC) that can be used to enhance the transient response of DC transmission systems. The schemes enable H-bridge MMC cell capacitor voltages to be regulated independent of the DC link voltage in a DC transmission system, and also permit operation with variable DC link voltage, down to zero voltage, with full control over active and reactive power exchange. The proposed schemes also offer protection functionality during a pole-to-pole DC fault by restraining the DC fault current magnitude in the converter arms to a level compatible with the current rating of the converter switching devices. The modulation and control schemes use the perturbations in the cell capacitor voltages and common mode currents of an individual phase to eliminate the second-order harmonics from each converter arm. This is achieved without a dedicated controller for suppression of the second-order harmonics. The validity of the proposed modulation and control schemes is confirmed using simulations and experimentation in open and close loop using a scaled down H-bridge MMC. Their viability in DC transmission systems is assessed using simulation of point-to-point and multi-terminal DC networks; this includes power transmission with reduced DC link voltage and survival from permanent and temporary DC faults with DC link controlled recharging following fault clearance. The major practical implication of the proposed modulation and control schemes is that they offer the possibility for voltage source converter based DC transmission systems to ride-through DC faults without the need for expensive and fast DC circuit breakers, as is being pursued by HVDC manufacturers. This thesis demonstrates the possibility of operation without converter blocking, without risk of converter damage from excessive current stresses. In this manner, a converter station of the DC transmission system can be used during a DC fault to provide voltage support to an AC grid.
Book Synopsis Design, Control and Protection of Modular Multilevel Converter (MMC)-based Multi-terminal HVDC System by : Yalong Li
Download or read book Design, Control and Protection of Modular Multilevel Converter (MMC)-based Multi-terminal HVDC System written by Yalong Li and published by . This book was released on 2016 with total page 205 pages. Available in PDF, EPUB and Kindle. Book excerpt: Even though today's transmission grids are predominantly based on the high voltage alternating current (HVAC) scheme, interests on high voltage direct current (HVDC) are growing rapidly during the past decade, due to the increased penetration of remote renewable energy. Voltage source converter (VSC) type is preferred over the traditional line-commutated converter (LCC) for this application, due to the advantages like smaller station footprint and no need for strong interfacing ac grid. As the state-of-the-art VSC topology, modular multilevel converter (MMC) is mostly considered. Most renewable energy sources, such as wind and solar, is usually sparsely located. Multi-terminal HVDC (MTDC) provides better use of transmission infrastructure, higher transmission flexibility and reliability, than building multiple point-to-point HVDCs. This dissertation studies the MMC-based MTDC system, including design, control and protection. Passive components design methodology in MMC is developed, with practical consideration. The developed arm inductance selection criterion considers the implementation of circulating current suppression control. And the unbalanced voltage among submodule capacitor is taken into account for submodule capacitance design. Circulating current suppression control is found to impact the MMC operating range. The maximum modulation index reduction is calculated utilizing a decoupled MMC model. A four-terminal HVDC testbed is developed, with similar control and communication architectures of the practical projects implemented. Several most typical operation scenarios and controls are demonstrated or proposed. In order to allow HVDC disconnects to online trip a line, dc line current control is proposed through station control. Utilizing the dc line current control, an automatic dc line current limiting control is proposed. Both controls have been verified in the developed testbed. A systematic dc fault protection strategy of MTDC utilizing hybrid dc circuit breaker is developed, including a new fast and selective fault detection method taking advantage of the hybrid dc circuit breaker special operation mechanism. Detailed criteria and control methods to assist system recovery are presented. A novel fault tolerant MMC topology is proposed with a hybrid submodule by adding an ultra-fast mechanical switch. The converter power loss can be almost the same as the half-bridge MMC, and 1/3 reduction compared to the similar clamp-double topology.
Book Synopsis Analytical Efficiency Evaluation of Modular Multilevel Converter (MMC) for High Voltage Direct Current System (HVDC) by : Ehtasham Mustafa
Download or read book Analytical Efficiency Evaluation of Modular Multilevel Converter (MMC) for High Voltage Direct Current System (HVDC) written by Ehtasham Mustafa and published by GRIN Verlag. This book was released on 2016-02-25 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: Master's Thesis from the year 2014 in the subject Electrotechnology, University of Peshawar (University of Engineering and Technology, Peshawar, Pakistan), course: High Voltage Direct Current, language: English, abstract: Modular Multilevel Converter (MMC) has become the most concerned converter topology in the High Voltage Direct Current (HVDC) transmission system, in recent times. The low switching frequency, low converter losses and flexible control made it most attractive topology. It is important to make a research on the loss calculation method of MMC and state formulae for the losses as it is a vital step during the design stage of the MMC based HVDC system. In this research work, the structure of MMC based HVDC system is discussed. Three sub module topologies’; half bridge, full bridge and clamp double sub module, are discussed. A method based on the average and root mean square (RMS) values of the current passing through the sub module is discussed. The conversion losses in the switching devices of the sub modules are calculated using the method. A cases study is taken into consideration then with certain parameters. Using these parameters a MATLAB program is developed. With the help of the program the losses and efficiency curves for each switching device by taking each sub module separately are obtained respectively. A comparison of the losses and efficiency of each sub module is also discussed. At the end those factors which effect the losses and efficiency of the sub module are discussed along with the certain aspects for the directions of future work.
Book Synopsis Power Electronics and Power Quality by : José Gabriel Oliveira Pinto
Download or read book Power Electronics and Power Quality written by José Gabriel Oliveira Pinto and published by MDPI. This book was released on 2020-04-23 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: Power quality (PQ) is receiving more and more attention from consumers, distribution system operators, transmission system operators, and other entities related to electrical power systems. As PQ problems have direct implications for business productivity, causing high economic losses, the research and development monitoring technologies and power electronics solutions that ensure the PQ of the power systems are matters of utmost importance. This book is a collection of high quality papers published in the “Power Electronics and Power Quality” Special Issue of the journal Energies. It reflects on the latest investigations and the new trends in this field.
Book Synopsis Flexible Power Transmission by : Jos Arrillaga
Download or read book Flexible Power Transmission written by Jos Arrillaga and published by John Wiley & Sons. This book was released on 2007-09-27 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of power semiconductors with greater ratings and improved characteristics has meant that the power industry has become more willing to develop new converter configurations. These new configurations take advantage of the higher controllability and switching frequencies of the new devices. The next few years will decide which of the proposed technologies will dominate future power transmission systems. Flexible Power Transmission is a comprehensive guide to the high voltage direct current (HVDC) options available, helping the reader to make informed decisions for designing future power transmission systems. The book includes: a full description of the principles and components in existing converter technology, as well as alternative proposals for self-commutating conversion; A review of the state of power semiconductors suited to HVDC transmission and present proposals for multi-level HVDC transmission. a detailed overview of the flexible HVDC methods for improving controllability and increasing power transfer capability in electrical power systems. up-to-date information on thyrisistor-based HVDC technology. coverage of new pulse width modulation (PWM) transmission technology and multi-level voltage source conversion (VSC) and current source conversion (CSC). An excellent reference for professional power engineers, Flexible Power Transmission is also a useful guide for power system researchers as well as lecturers and students in power systems and power electronics disciplines.
Book Synopsis Hybrid Cascaded Modular Multilevel Converters for HVDC Transmission by : Xianghua Shi
Download or read book Hybrid Cascaded Modular Multilevel Converters for HVDC Transmission written by Xianghua Shi and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents a comprehensive study of a class of modular multilevel converters (MMCs) namely hybrid cascaded MMCs. These converters have topological dc-fault blocking capability and are suitable for large-scale, long-distance high-voltage direct current (HVDC) transmission. This thesis investigates an existing hybrid cascaded MMC (HC-MMC) and novel variations thereof (mixed-SM HC-MMC) with a multi-pronged research approach based upon mathematical analyses, detailed computer simulations, and where possible experimental verifications. Several methods are proposed for control and operation of the converter under normal and faulted conditions with a view to (i) enable regulation of submodule capacitor voltages in the phase limb with reduced harmonics and the ability of extending linear modulation range, (ii) ride through balanced and unbalanced ac faults with balanced phase currents and efficient ac-fault recovery, and (iii) successfully ride through dc faults with prompt isolation of the ac and dc sides and rapid decay of the dc fault current. These methods are extensively analyzed using detailed electromagnetic transient simulation and experimental work where possible. Converter losses and efficiency maps are also quantified using detailed computer modeling methods to evaluate the benefits of the existing and proposed HC-MMCs. Compared with the original HC-MMC, the proposed mixed-SM HC-MMC has superior performance in terms of extended linear modulation range, system efficiency, and dc-fault clearing performance. The thesis also formulates the design guidelines of SM capacitor sizing considering submodule redundancy and different control modes. Extensive analytical, simulation-based, and experimental measurements are provided to confirm the validity and efficacy of the developed guidelines.
Book Synopsis Modular Multilevel Converters with Interleaved Half-Bridge Submodules by : Aleksandr Viatkin
Download or read book Modular Multilevel Converters with Interleaved Half-Bridge Submodules written by Aleksandr Viatkin and published by Springer Nature. This book was released on 2023-03-29 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reports on a comprehensive study on a novel high-power converter, i.e. a Modular Multilevel Converter with Interleaved Half-bridge Submodules (ISM-MMC). It describes in depth its average model, the operating principles, as well as a new control method and a hybrid modulation strategy that help to exploit the benefits of the interleaving scheme. The new power converter is particularly advantageous for high-current applications that require superb quality of input/output waveforms. Moreover, this book reports on a systematic study of the current balancing problem between parallel-connected units that commutate in non-simultaneous fashion. This is a typical issue in interleaved converters, however here it is analyzed for the first time in relation to MMC-based structures. Two control strategies are proposed to cope with this matter. By using a sensorless regulation scheme, the number of required current transducers has been minimized, reducing complexity, cost, and footprint of the hardware, while providing converter with a fast and accurate current balancing. This book also offers a comprehensive comparison between several practical designs of ISM-MMC and classical MMC for an ultra-fast electrical vehicle charger. All in all, it provides graduate students and researchers, as well as field engineers and professionals with extensive information and essential practical details on the state-of-the-art MMC and ISM-MMC design.
Book Synopsis Reduced-order Modeling of the Parallel Hybrid Modular Multilevel Converter by : Curtis Shumski
Download or read book Reduced-order Modeling of the Parallel Hybrid Modular Multilevel Converter written by Curtis Shumski and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: As the demand for electrical power continues to increase, so does the attractiveness of high voltage direct current (HVDC) transmission networks to transfer power from generating stations to load centers. Located at either end of the HVDC transmission network are converter stations that convert the AC power into DC power, and vice versa. A voltage source converter (VSC) commonly used in practice is the modular multilevel converter (MMC); however, these converters require many power electronic switches that will significantly increase the cost of such HVDC networks. A cost-effective alternative to these converters is the parallel hybrid MMC (PH-MMC), which is the focus of this thesis. Modeling VSCs in large electrical networks can be a computational burden as a small time step is required to capture all of the switching transients of the VSC. In some situations, it may not be necessary to simulate every switching instant, and instead a reduced-order model can be utilized. The reduced order model of VSCs retain the behavior of the converters, while being able to run at a larger time step and at a much faster simulation runtime. The basic principles of MMCs are first derived and the topological changes of the PH-MMC are analyzed. Comparisons between the PH-MMC and conventional MMCs are drawn to showcase the advantages and disadvantages of the PH-MMC. Control algorithms are described for basic operation of the PH-MMC, and control block diagrams are detailed to control the sub-module capacitor voltages as well as the AC terminal outputs. A qualitative fault analysis is provided for both AC and DC side faults, and a reduced-order model is developed to accurately model the PH-MMC in electromagnetic transient (EMT) studies by removing the need to model high frequency switching instants. Using a simple network model and a more complex network model, dynamic simulations are performed in PSCADTM/EMTDCTM software to validate the reduced-order model against the full, detailed switching model. Simulation results show that the developed reduced-order model is an accurate representation of the PH-MMC, while significantly decreasing the runtime to carry out such simulations as compared to the detailed model. When incorporating PH-MMCs into larger networks, the reduced-order model developed in this thesis can be used to alleviate the computational burden of using a small time step while maintaining the low frequency behavior of the converter.
Book Synopsis Multilevel Converters by : Salman Ahmad
Download or read book Multilevel Converters written by Salman Ahmad and published by John Wiley & Sons. This book was released on 2024-07-03 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt: Discover the deep insights into the operation, modulation, and control strategies of multilevel converters, alongside their recent applications in variable speed drives, renewable energy generation, and power systems. Multilevel converters have gained attention in recent years for medium/high voltage and high power industrial and residential applications. The main advantages of multilevel converters over two level converters include less voltage stress on power semiconductors, low dv/dt, low common voltage, reduced electromagnetic interference, and low total harmonics distortion, among others. Better output power quality is ensured by increasing the number of levels in the synthesized output voltage waveform. Several multilevel topologies have been reported in the literature, such as neutral point clamped (NPC), flying capacitor (FC), cascaded H-bridge (CHB), hybrid cascaded H-bridge, asymmetrical cascaded H-bridge, modular multilevel converters (MMC), active neutral point clamped converters (ANPC), and packed U-cell type converters and various reduced device counts and a reduced number of source-based topologies have been proposed in literature. The multilevel converter, although a proven and enabling technology, still presents numerous challenges in topologies, modulation, and control, as well as in need-based applications. Since multilevel converters offer a wide range of possibilities, research and development in the areas of multilevel converter topologies, modulation, and control in various applications are still growing. To further improve multilevel converter energy efficiency, reliability, power density, and cost, many research groups across the world are working to broaden the application areas of multilevel converters and make them more attractive and competitive compared to classic topologies. Multilevel Converters intends to provide deep insight about multilevel converter operation, modulation, and control strategies and various recent applications of multilevel converters such as in variable speed drives, renewable energy generation, and power systems.
