2,067 research outputs found

    Control of wind energy conversion systems based on the Modular Multilevel Matrix converter

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    The nominal power of single Wind Energy Conversion Systems (WECS) has been steadily growing, reaching power ratings close to 10MW. In the power conversion stage, medium-voltage power converters are replacing the conventional low-voltage back-to-back topology. Modular Multilevel Converters have appeared as a promising solution for Multi-MW WECSs, due to their modularity, and the capability to reach high nominal voltages. This paper discusses the application of the Modular Multilevel Matrix Converter (M3C) to drive MultiMW WECSs. The modelling and control systems required for this application are extensively analysed and discussed in this paper. The proposed control strategies enable decoupled operation of the converter, providing maximum power point tracking (MPPT) capability at the generator-side, grid code compliance at the grid-side [including Low Voltage Ride Through Control (LVRT)], and good steady state and dynamic performance for balancing the capacitor voltages in all the clusters. Finally, the effectiveness of the proposed control strategy is validated through simulations and experimental results conducted with a 27 power-cell prototype

    An Overview of Applications of the Modular Multilevel Matrix Converter

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    The modular multilevel matrix converter is a relatively new power converter topology suitable for high-power alternating current (AC)-to-AC applications. Several publications in the literature have highlighted the converter capabilities, such as full modularity, fault-redundancy, control flexibility and input/output power quality. However, the topology and control of this converter are relatively complex to realise, considering that the converter has a large number of power-cells and floating capacitors. To the best of the authors’ knowledge, there are no review papers where the applications of the modular multilevel matrix converter are discussed. Hence, this paper aims to provide a comprehensive review of the state-of-the-art of the modular multilevel matrix converter, focusing on implementation issues and applications. Guidelines to dimensioning the key components of this converter are described and compared to other modular multilevel topologies, highlighting the versatility and controllability of the converter in high-power applications. Additionally, the most popular applications for the modular multilevel matrix converter, such as wind turbines, grid connection and motor drives, are discussed based on analyses of simulation and experimental results. Finally, future trends and new opportunities for the use of the modular multilevel matrix converter in high-power AC-to-AC applications are identified.Agencia Nacional de Investigación y Desarrollo/[Fondecyt 11191163]/ANID/ChileAgencia Nacional de Investigación y Desarrollo/[Fondecyt 1180879]/ANID/ChileAgencia Nacional de Investigación y Desarrollo/[Fondecyt 11190852]/ANID/ChileAgencia Nacional de Investigación y Desarrollo/[ANID Basal FB0008]/ANID/ChileAgencia Nacional de Investigación y Desarrollo/[Fondef ID19I10370]/ANID/ChileUniversidad de Santiago/[Dicyt 091813DD]//ChileUCR::Vicerrectoría de Docencia::Ingeniería::Facultad de Ingeniería::Escuela de Ingeniería Eléctric

    Analysis of optimized multilevel matrix converter for DFIG based wind energy conversion system

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    Wind power generation is an increasing trend worldwide. Multilevel converters in this regard are playing an essential role in high power system applications due to various features. In this paper, multi-objective optimization based multilevel matrix converter (MOMMC) is proposed for wind energy conversion system. The assessment of feasibility through the discussion of two objectives: reliability and cost have been considered in this study. Initially, the model of the two objectives is assessed against redundancy configuration and power loss. Then a multi-objective function is defined for achieving low cost and high reliability. The optimal topology for the matrix multi-level converter is determined using the membership function, and the solution is selected from the Pareto-optimal set. The reliability and cost analysis of the proposed MOMMC is performed. Simulation is carried out for the proposed multi-objective optimization based multilevel matrix converter using the PSIM software. To establish the validity of the proposed method, two different cases: 1) fixed and 2) variable speed of 9 MW doubly-fed induction generator-based wind energy system are considered. The results show the superiority of the proposed method over the others.

    Solid state transformer technologies and applications: a bibliographical survey

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    This paper presents a bibliographical survey of the work carried out to date on the solid state transformer (SST). The paper provides a list of references that cover most work related to this device and a short discussion about several aspects. The sections of the paper are respectively dedicated to summarize configurations and control strategies for each SST stage, the work carried out for optimizing the design of high-frequency transformers that could adequately work in the isolation stage of a SST, the efficiency of this device, the various modelling approaches and simulation tools used to analyze the performance of a SST (working a component of a microgrid, a distribution system or just in a standalone scenario), and the potential applications that this device is offering as a component of a power grid, a smart house, or a traction system.Peer ReviewedPostprint (published version

    Continuous Set Model Predictive Control for Energy Management of Modular Multilevel Matrix Converters

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    The Modular Multilevel Matrix Converter is an AC-AC power converter proposed for high power applications such as motor drive and wind energy conversion systems. The M 3C has 9 clusters, allowing 4 circulating currents for converter energy management. Control of the M 3C is frequently divided into Different Frequency Mode (DFM) and Equal Frequency Mode (EFM). EFM is more challenging, because of the larger capacitor voltage oscillations that can be produced. Conventional energy management control strategies for EFM/DFM are usually based on 8 energy control loops used to define four circulating current references composed of several predefined frequencies and positive/negative sequences. The control schemes are typically different for EFM/DFM operation increasing the complexity. In this paper, a Continuous-Control-Set Model Predictive Control (CCS-MPC) for energy management of the M 3C is proposed. The control scheme is based on solving an equality constrained quadratic programming problem, using a state variable model of the M3C, where the optimal solution is analytically obtained. The result is a single and simple control law to obtain circulating current references during EFM/DFM, ensuring a good performance with optimal current specifications. The proposed strategy is experimentally validated using a down-scaled M3C prototype composed of 27 power cells

    Control and grid integration of MW-range wind and solar energy conversion systems

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    Solar-based energy generation has increased by more than ten times over the same period. In total, worldwide electrical energy consumption increased by approximately 6340 TWh from 2003 to 2013. To meet the challenges created by intermittent energy generation sources, grid operators have increasingly demanded more stringent technical requirements for the connection and operation of grid-connected intermittent energy systems, for instance concerning fault ride through capability, voltage and frequency support, and inertia emulation. Ongoing developments include new or improved high-voltage converters, power converters with higher power density, control systems to provide ride-through capability, implementation of redundancy schemes to provide more reliable generation systems, and the use of high-voltage direct current (HVdc) links for the connection of large off-shore intermittent energy systems

    Modular Multilevel Converters with Module-Level Energy Storage for Medium Voltage Applications

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    This dissertation is on Modular Multilevel Converter (MMC) converter design and analysis and its integration with energy storage at the low voltage module-level. The developed converter concept and topology can be used in various applications especially for the support of intermittent renewable energy resources. The general converter structure is analyzed and extended to include integrated energy storage suitable but not limited to medium voltage applications. The behavior of the idealized structure is analyzed to obtain equations that govern general converter behavior and identify possible control loops. Detail mathematical switching model is developed for the MMC converter with generalized module structure. The switching model is averaged to obtain a large signal model and then reduced to obtain lower order models suitable for sizing and optimization. Open and compensated closed loop current control is proposed and extended to include feedback loops needed for full control of integrated energy storage. General sizing procedure with the optimization aspects is then proposed and used on the example system to obtain the converter structure parameters. The example system models are then used to fine tune the control and structure parameters and investigate the converter behavior

    An Overview of Modelling Techniques and Control Strategies for Modular Multilevel Matrix Converters

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    The Modular Multilevel Matrix Converter is a relatively new power converter topology appropriate for high-power Alternating Current (AC) to AC purposes. Several publications in the literature have highlighted the converter capabilities such as modularity, control flexibility, the possibility to include redundancy, and power quality. Nevertheless, the topology and control of this converter are relatively complex to design and implement, considering that the converter has a large number of cells and floating capacitors. Therefore multilayer nested control systems are required to maintain the capacitor voltage of each cell regulated within an acceptable range. There are no other review papers where the modelling, control systems and applications of the Modular Multilevel Matrix Converter are discussed. Hence, this paper aims to facilitate further research by presenting the technology related to the Modular Multilevel Matrix Converter, focusing on a comprehensive revision of the modelling and control strategies.Agencia Nacional de Investigacion y Desarrollo (ANID) of Chile Fondecyt 11191163 Fondecyt 1180879 Fondecyt 11190852 Fondef ID19I10370 University of Costa Rica 322-B9242 University of Santiago Dicyt 091813D

    Solid state transformers topologies, controllers, and applications: State-of-the-art literature review

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    With the global trend to produce clean electrical energy, the penetration of renewable energy sources in existing electricity infrastructure is expected to increase significantly within the next few years. The solid state transformer (SST) is expected to play an essential role in future smart grid topologies. Unlike traditional magnetic transformer, SST is flexible enough to be of modular construction, enabling bi-directional power flow and can be employed for AC and DC grids. Moreover, SSTs can control the voltage level and modulate both active and reactive power at the point of common coupling without the need to external flexible AC transmission system device as per the current practice in conventional electricity grids. The rapid advancement in power semiconductors switching speed and power handling capacity will soon allow for the commercialisation of grid-rated SSTs. This paper is aimed at introducing a state-of-the-art review for SST proposed topologies, controllers, and applications. Additionally, strengths, weaknesses, opportunities, and threats (SWOT) analysis along with a brief review of market drivers for prospective commercialisation are elaborated

    New configurations of power converters for grid interconnection systems

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    The increased penetration of renewable energy sources and other distributed energy sources has been seen nowadays. In this scenario power converters play a crucial role by providing the interconnection of these energy sources. This paper presents new configurations of power converters for grid interconnection systems. Several topologies are analyzed which are based on isolated ac-ac matrix converters
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