Статті в журналах: "Multilevel Power Converters"

1

Verdugo, Cristian, Samir Kouro, Christian A. Rojas, Marcelo A. Perez, Thierry Meynard, and Mariusz Malinowski. "Five-Level T-type Cascade Converter for Rooftop Grid-Connected Photovoltaic Systems." Energies 12, no. 9 (May 8, 2019): 1743. http://dx.doi.org/10.3390/en12091743.

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Multilevel converters are widely considered to be the most suitable configurations for renewable energy sources. Their high-power quality, efficiency and performance make them interesting for PV applications. In low-power applications such as rooftop grid-connected PV systems, power converters with high efficiency and reliability are required. For this reason, multilevel converters based on parallel and cascaded configurations have been proposed and commercialized in the industry. Motivated by the features of multilevel converters based on cascaded configurations, this work presents the modulation and control of a rooftop single-phase grid-connected photovoltaic multilevel system. The configuration has a symmetrical cascade connection of two three-level T-type neutral point clamped power legs, which creates a five-level converter with two independent string connections. The proposed topology merges the benefits of multi-string PV and symmetrical cascade multilevel inverters. The switching operation principle, modulation technique and control scheme under an unbalanced power operation among the cell are addressed. Simulation and experimental validation results in a reduced-scale power single-phase converter prototype under variable conditions at different set points for both PV strings are presented. Finally, a comparative numerical analysis between other T-type configurations to highlight the advantages of the studied configuration is included.

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2

Dybko, Maxim, Sergey Brovanov, and Hong Hee Lee. "Multilevel NPC Converters in Parallel Connection for Power Conditioning Systems." Applied Mechanics and Materials 792 (September 2015): 189–96. http://dx.doi.org/10.4028/www.scientific.net/amm.792.189.

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This paper investigates a multilevel combined NPC converter for medium-and high-power energy storage systems and active power filters. The proposed multilevel NPC converter is composed of a parallel connection of multiple NPC converters using the current sharing reactors and involves the phase shifted PWM strategy for better energy quality performance. Using the switching function-based mathematical model, the proposed multilevel converter is evaluated to show the energy quality performance and fault tolerance of an energy storage system or active power filter. In addition, the switching frequency of circulating currents is analyzed to obtain its relationship with the converter parameters and maximum sharing reactor current ripple. The performance of the proposed multilevel converter is verified by simulation.

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Mei, Zhiting, Jingyang Fang, and Stefan Goetz. "Control and Optimization of Lattice Converters." Electronics 11, no. 4 (February 15, 2022): 594. http://dx.doi.org/10.3390/electronics11040594.

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Multilevel converters continue their upward trend in renewable generation, electric vehicles, and power quality conditioning applications. Despite having satisfactory voltage capabilities, mainstream multilevel converters suffer from poor current sharing performances, thereby leading to the development of lattice converters, i.e., a strong and versatile type of future multilevel power converters. This article addresses two problems faced by lattice converters. First, we propose and detail how to optimize the efficiency of a given lattice converter by controlling the on/off states of H-bridge submodules. Second, we introduce the method that determines the voltage at each node of the converter in order to satisfy output voltage and current requirements. Design and analysis of lattice converters need a different mathematical toolbox than routinely exercised in power electronics. By use of graph theory, this article provides control methods of 3 × 3 and 4 × 4 lattice converters, satisfying various control objectives such as input/output terminals and output voltages. We further validate the methods with simulation results. The methodologies, algorithms, and special cases described in the article will aid further design and refinement of more efficient and easy-to-control lattice converters.

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4

G, Ramya, and Ramaprabha R. "A Review on Designand Control Methods of Modular Multilevel Converter." International Journal of Power Electronics and Drive Systems (IJPEDS) 7, no. 3 (September 1, 2016): 863. http://dx.doi.org/10.11591/ijpeds.v7.i3.pp863-871.

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Modular multilevel converters (MMC) are an emerging voltage source converter topology suitable for many applications. Due to abundant utilization of HVDC power transmission, the modular multilevel converter has become popular converter type to be used in high voltage applications. Other applications include interfacing renewable energy power sources to the grid and motor drives. Modular multilevel converters are beneficial for high voltage and high power motor drives because of the properties of this converter topology, such as, low distortion, high efficiency, etc. For the past few years significant research has been carried out to address the technical challenges associated with operation and voltage balancing of MMC. In this paper, a detailed technical review on the control strategies is presented for ready reference.

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5

Mechouma, Rabiaa, and Boubekeur Azoui. "Multiple low frequency dual reference PWM control of a grid connected photovoltaic three phase NPC inverter with DC/DC boost converter." Serbian Journal of Electrical Engineering 11, no. 2 (2014): 315–37. http://dx.doi.org/10.2298/sjee1402315m.

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In recent years, power demand of industrial applications has increased significantly reaching some megawatts. The use of multilevel converters for applications of medium and high powers is proposed as a solution to drawback semiconductor technology. A multilevel converter not only achieves high power ratings, but also enables the use of renewable energy sources. Renewable energy sources such as photovoltaic can be easily interfaced to a multilevel converter system for a high power application. This paper presents the simulation study in Matlab/Simulink of a grid connected photovoltaic three phase Neutral Point Clamped (NPC) inverter with DC/DC boost converter for constant and variable solar radiation.

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6

Jih-Sheng Lai and Fang Zheng Peng. "Multilevel converters-a new breed of power converters." IEEE Transactions on Industry Applications 32, no. 3 (1996): 509–17. http://dx.doi.org/10.1109/28.502161.

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Paulo, Matheus Sene, Andrei de Oliveira Almeida, Pedro Machado de Almeida, and Pedro Gomes Barbosa. "Control of an Offshore Wind Farm Considering Grid-Connected and Stand-Alone Operation of a High-Voltage Direct Current Transmission System Based on Multilevel Modular Converters." Energies 16, no. 16 (August 9, 2023): 5891. http://dx.doi.org/10.3390/en16165891.

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This work presents a control strategy for integrating an offshore wind farm into the onshore electrical grid using a high-voltage dc transmission system based on modular multilevel converters. The proposed algorithm allows the high-voltage DC system to operate in grid-connected or stand-alone modes, with the second case supplying power to local loads. In either mode, the modular multilevel rectifier works as a grid-forming converter, providing the reference voltage to the collector network. During grid-connected operation, the modular multilevel inverter regulates the DC link voltage while the generating units are controlled to maximize power extracted from the wind turbines. Conversely, in the event of grid disconnection, the onshore modular multilevel converter takes over the regulation of the AC voltage at the point of connection to the grid, ensuring energy supply to local loads. Simultaneously, the generator controller transitions from tracking the maximum power of the wind turbines to regulating the DC link voltage, preventing excessive power injection into the transmission DC link. Additionally, the turbine pitch angle control regulates the speed of the generator. Mathematical models in the synchronous reference frame were developed for each operation mode and used to design the converter’s controllers. A digital model of the wind power plant and a high-voltage dc transmission system was implemented and simulated in the PSCAD/EMTDC program. The system modeled includes two groups of wind turbines, generators, and back-to-back converters, in addition to a DC link with a rectifier and an inverter station, both based on modular multilevel converters with 18 submodules per arm, and a 320 kV/50 km DC cable. Aggregate models were used to represent the two groups of wind turbines, where 30 and 15 smaller units operate in parallel, respectively. The performance of the proposed control strategy and the designed controllers was tested under three distinct scenarios: disconnection of the onshore converter from the AC grid, partial loss of a wind generator set, and reconnection of the onshore converter to the AC grid.

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8

Jeong, In Wha. "DC-Link Capacitor Voltage Balancing Control of a Five-Level Regenerative AC Electronic Load Using One-Cycle Control." Energies 14, no. 19 (September 24, 2021): 6101. http://dx.doi.org/10.3390/en14196101.

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High voltage electric power equipment requires rigorous regulation testing to specific standards which ensure proper and safe operation in the grid. Manufacturers conduct these tests in order to prove standard compliance and product liability. Variable linear or nonlinear loads are necessary for testing medium voltage (MV) high power AC power converters. Generally, those AC power converters or power supplies require performance validation, burn-in and/or lifetime testing under different load conditions, defined by the end-user or standards for the given applications. For flexible and efficient MV verification testing, this paper presents a five-level multilevel converter-based MV regenerative AC electronic load with one-cycle control (OCC), which is based on five-level diode-clamped multilevel converters with back-to-back structure and can emulate any impedance load. In this paper, especially the dc-link capacitor voltage balance of the proposed multilevel MV regenerative AC load is deeply analyzed. Simulation and experimental results are presented to verify the dc-link voltage balance performance of the proposed multilevel MV regenerative AC electronic load.

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9

Majdoul, Radouane, Abelwahed Touati, Abderrahmane Ouchatti, Abderrahim Taouni, and Elhassane Abdelmounim. "A nine-switch nine-level converter new topology with optimal modulation control." International Journal of Power Electronics and Drive Systems (IJPEDS) 12, no. 2 (June 1, 2021): 932. http://dx.doi.org/10.11591/ijpeds.v12.i2.pp932-942.

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Multilevel power converters are becoming increasingly used in several sectors: energy, grid-tie renewable energy systems, High voltage direct current (HVDC) power transmission, and a multitude of industrial applications. However, the multilevel converters consist of several drives and a high number of power switches, which leads to a considerable cost and an increased size of the device. Thus, a novel topology of a multilevel bidirectional inverter using a reduced number of semiconductor power components is proposed in this paper. Without any diode clamped or flying capacitor, only nine switches are used to generate nine voltage levels in this new topology. The proposed multilevel converter is compared with the conventional structures in terms of cost, the number of active power switches, clamped diodes, flying capacitors, DC floating capacitors, and the number of DC voltage sources. This comparative analysis shows that the proposed topology is suitable for many applications. For optimum control of this multilevel voltage inverter and to reduce switching losses in power semiconductors, a hybrid modulation technique based on fundamental frequency modulation and multi-carrier-based sinusoidal pulse-width modulation schemes is performed. The effectiveness of the proposed multilevel power converter is verified by simulation results.

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10

Okhotkin, Grigory P., and Ivan I. Ivanchin. "SPACE VECTOR PWM IN A MULTILEVEL VOLTAGE CONVERTER." Vestnik Chuvashskogo universiteta, no. 1 (March 30, 2022): 107–14. http://dx.doi.org/10.47026/1810-1909-2022-1-107-114.

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The present article considers the voltage forming by multilevel converters. Multilevel converters are widely used in industry applications with medium voltages up to 20 kV. An example is the oil industry, where multilevel converters are installed in electric drives of pumping units on pipeline systems. The location of the pipelines in isolated areas implies weak net connections for power system and expects increased requirements for the efficiency of the use of electricity. In this regard, for a multilevel voltage converter, an energy-efficient vector method of pulse-width modulation is proposed. With vector pulse-width modulation, the optimal number of voltage level switching occurs in the phases of the converter, which leads to the lowest harmonic distortion of the voltage, compared with other modulation methods. The features of vector pulse-width modulation in multilevel voltage converters caused by the increased number of basic voltage vectors of a static multilevel converter are analyzed. A step-by-step method of vector pulse-width modulation in a multilevel converter is proposed, including determining the base vectors of the converter closest to a reference voltage vector, calculating the time for each of the base vectors, maintaining the switching order between the base vectors. The method is considered in detail for a multilevel converter with five voltage levels in a phase. In conclusion, the results of modeling control system of this converter with the proposed method of vector pulse-width modulation are presented. According to the obtained time diagrams of voltage formation, a hodograph of the resulting vector of the output voltage of a multilevel static converter was constructed.

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11

Shanono, Ibrahim Haruna, Nor Rul Hasma Abdullah, and Aisha Muhammad. "A Survey of Multilevel Voltage Source Inverter Topologies, Controls, and Applications." International Journal of Power Electronics and Drive Systems (IJPEDS) 9, no. 3 (September 1, 2018): 1186. http://dx.doi.org/10.11591/ijpeds.v9.i3.pp1186-1201.

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Multi-level converters are every day attracting research interest due to it tremendous positive contributions they are making in the power industries. The converter has put hope in the minds of power electronic engineers that a time will come when it will break a record by providing an efficient means of utilizing the abundant renewable energy resources. The paper presents a review of multilevel voltage source converters that are widely being used in engineering applications. It reports the technological advancements in converter topologies of Flying Capacitor (FC), Neutral Point (NPC) /Diode Clamped, and Cascaded H-Bridge (CHB) with their respective advantages and disadvantages. Recent customized/hybrid topologies of the three-phase multilevel inverter with reduced component count and switching combination are reported. The paper also reviewed different modulation techniques such as the multilevel converter carrier base PWM, Space Vector Modulation techniques (SVM), and Selective Harmonic Elimination method (SHE-PWM). Finally, various multilevel converters areas of application were highlighted. This review will expose the reader to the latest developments made in the multi-level topologies, modulation techniques, and applications.

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12

Mlodzikowski, Pawel, Adam Milczarek, and Mariusz Malinowski. "Application of Simplified Neutral Point Clamped Multilevel Converter in a Small Wind Turbine." Electrical, Control and Communication Engineering 5, no. 1 (May 1, 2014): 5–10. http://dx.doi.org/10.2478/ecce-2014-0001.

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Abstract In low power distributed generation systems low cost together with the energy quality requirements are a key element. It is known that quality of voltage waveforms generated from multilevel converters is better in comparison with those from two-level. Due to advancements in power electronics and microcontrollers, multilevel converters are being built with the use of integrated power modules thus this type of converters are getting more compact in size. This paper investigates performance of a derivation from the most popular multilevel topology - a neutral point clamped converter (NPC). Applying the idea for simplifying the topology by reducing the number of switches (what came from drives) this NPC converter is capable of bidirectional AC/DC/AC operation. For the AC/DC part two schemes are tested: Direct Torque Control Space Vector Modulated and Field Oriented Control but for the DC/AC part a control scheme utilizing the proportional-resonant controller was chosen. Laboratory setup was based on a permanent magnet synchronous generator with control and acquisition completed with the help of dSpace 1005 control box. Experimental verification shows that system operates properly.

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13

Nguyen, Phu Cong, Quoc Dung Phan, and Dinh Tuyen Nguyen. "A New Decentralized Space Vector PWM Method for Multilevel Single-Phase Full Bridge Converters." Energies 15, no. 3 (January 29, 2022): 1010. http://dx.doi.org/10.3390/en15031010.

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This paper proposes a decentralized control structure and method for a multilevel single-phase power converter using space vector pulse width modulation (SVPWM). The focus of this paper is on the decentralized control structure for the power converter cells that will exchange information with neighboring cells in order to adjust the switching vector and switching time for each cell. In this study, the switching vectors and the corresponding switching times of each cell will be self-determined based on the phase angle of two neighboring cells. Normally, SVPWM applied to the multilevel power converters need complete information about the total cells and cell’s position to build a control algorithm. Meanwhile, a decentralized space vector pulse width modulation (DSVPWM) method is proposed that can be applied to power converters with any number of cells and can be considered as a multilevel SVPWM method. In addition, the decentralized multilevel single-phase power converter has high flexibility with which it is possible to easily adjust the number of active cells, so that the output voltage can be adjusted quickly; this provides the ability to dynamically reconfigure without interrupting the power energy supply process. The proposed control structure and method are effectively verified based on simulation and experimental results. Experimental results are evaluated based on a 9-level single-phase power converter, which has an RL load with rated parameters 220 V/500 W.

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14

Bettoni, Samuel dos Santos, Herbert de Oliveira Ramos, Frederico F. Matos, and Victor Flores Mendes. "Cascaded H-Bridge Multilevel Converter Applied to a Wind Energy Conversion System with Open-End Winding." Wind 3, no. 2 (May 9, 2023): 232–52. http://dx.doi.org/10.3390/wind3020014.

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With the growing expansion of renewable sources around the world, wind energy is among those that stand out. With the advances of technology, wind turbine projects have considerably increased their power, reaching higher power, mainly for offshore installations. One of the main challenges is the power converters, more specifically the semiconductor components, which have limited voltage and current capabilities. Thus, the concept of multilevel converters emerged, increasing the voltage levels and thus carrying higher power levels. In addition to the application of multilevel converters, it is possible to increase the voltage and power levels employing an open-end winding (OEW) connection to the generator. In this context, the present work investigated the application of a multilevel converter (three-level cascaded H-bridge back-to-back) driving a squirrel-cage induction machine in an open-end winding configuration, connected to a wind energy conversion system (WECS). The analysis of the proposed system was developed through dynamic simulation of a 1.67 MW WECS, using PLECS software, including the modeling of the main system components: generator, power converters, system control, filter, and grid connection. The results show that the objective of obtaining a 5-level behavior in the output voltage is achieved by using the OEW connection. Furthermore, a low harmonic content is achieved in the machine current as in the current injected into the grid. In addition, it is possible to verify the power distribution between the converters, demonstrating that converters with smaller power can be combined to reach higher WECS power.

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Korzhov, A. V., Yu I. Khokhlov, M. A. Grigorev, D. Yu Khryukin, and V. A. Kushnarev. "IMPROVING POWER AND RELIABILITY OF MULTILEVEL FREQUENCY CONVERTERS FOR DRILLING RIGS." Bulletin of the South Ural State University series "Power Engineering" 21, no. 4 (2021): 94–101. http://dx.doi.org/10.14529/power210411.

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Modern electric drives used in the oil and gas sector are made based on two-level power circuits for volta¬ges up to 1 kV and have a modular cabinet design. The paper presents improvements based on the op-timization of the number of modular frequency converters aimed at insuring smooth operation of critical oil and gas applications. Using the method of numerical analysis, the criteria for optimizing the number of phases of the power circuits of the converter in terms of cost, electrical losses and reliability were derived, based on the data on the cost of two-level frequency converters. An economic justification for reducing capital and operating costs when using multilevel frequency converters is given. It is revealed that the proposed optimization methods allow reducing electrical losses due to the reduction of overvoltages on the electromechanical con-verter, as well those in the DC link. The reliability increase is determined by the operability of the electro-mechanical converter in the event of a failure of one of its phase winding, taking into account the decrease in the installed power. The results of the introduction of multilevel frequency converters “MOMENTUM” of the MT-1000/MT-2000 series of the Scientific and Technical Center “Privodnaya Tekhnika” LLC are presented.

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16

Li, Li Juan, You Gui Guo, and Ping Zeng. "Wind Power System Based on Multilevel Matrix Converter." Advanced Materials Research 354-355 (October 2011): 1372–75. http://dx.doi.org/10.4028/www.scientific.net/amr.354-355.1372.

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A complete direct-driving wind power system consisting of wind turbine, permanent-magnet synchronous generator, multilevel matrix converter with voltage space vector modulation strategy is proposed in this paper. The simulation model is set up through Matlab/Simulink, and the results have verified the control strategy is feasible. Multilevel matrix converters are suitable for high- voltage application of wind power generation system, and it has laid a good basis for the real system development.

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17

D, Karthikeyan, Vijayakumar K, and Jagabar M. "Generalized Cascaded Symmetric and Level Doubling Multilevel Converter Topology with Reduced THD for Photovoltaic Applications." Electronics 8, no. 2 (February 1, 2019): 161. http://dx.doi.org/10.3390/electronics8020161.

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In this paper, two different converter topologies for a basic new switched capacitor diode converter with a reduced number of power electronics components, suitable for grid connected photovoltaic applications were proposed. The two different structures of switched diode multilevel converter proposed were: (i) cascaded switched diode and (ii) cascaded switched diode with doubling circuit. The switched-diode multilevel converter was compared with other recent converters. In addition, a new dc offset nearest level modulation technique was proposed. This proposed dc offset technique offers low voltage total harmonic distortion (THD) and high RMS output voltage. The proposed modulation technique was compared with conventional nearest level modulation (NLM) and modified NLM control techniques. The performance of the proposed dc offset modulation technique was implemented using a FPGA Spartan 3E controller and tested with a novel switched capacitor-diode multilevel converter. However, to prove the authenticity of the switched-diode multilevel converter and modulation technique, a laboratory-based prototype model for 7-level and 13-level converters was developed.

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18

Wei, Chen, Xibo Yuan, Juan Zhou, Kangan Wang, Yonglei Zhang, and Xiaojie Wu. "Voltage Jump Suppression and Capacitor Voltage Fluctuation Analysis for a Four-Level Hybrid Flying Capacitor T-Type Converter." Energies 12, no. 4 (February 21, 2019): 698. http://dx.doi.org/10.3390/en12040698.

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In low and medium voltage power conversion systems, multilevel converters are becoming more and more attractive due to improved power density. However, the complexity of topology and control is a big challenge for the application of multilevel converters. In this paper, a four-level (4L) hybrid flying capacitor (FC) T-type converter has been researched in detail. The topological advantage of the converter is displayed in comparison to existing four-level converters. According to the feature of the topology, the operating status has been analyzed and the reason for the voltage jump is researched in detail during the dead-time period. A strategy to reduce voltage jump by adjusting the switching states has be presented. The FC voltages can be balanced by selecting the appropriate switching states. The relationships between the fluctuations of FC voltages and the modulation index and power factor (PF) have been analyzed by simulation results. The performance of the 4L converter has been investigated in MATLAB/Simulink as well as on a down-scaled laboratory prototype.

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19

Melnikov, V., O. Talipov, and Yu Kibartene. "EVALUATING THE POSSIBILITY OF APPLYING CONTROLLED COMPENSATION SYSTEMS TO IMPROVE EFFICIENCY IN ELECTRIC GRIDS." Bulletin of Toraighyrov University. Energetics series, no. 2021.3 (September 11, 2021): 83–92. http://dx.doi.org/10.48081/jbmz50037.

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The paper considers issues of increasing efficiency of multilevel power converter based on IGCT and IGBT modules to improve energy performance by compensating reactive power in electric networks. By the example of a local power grid using SEMIS SimulationTool design tool the results of calculations of variants of multilevel converters with IGCT and IGBT are presented. The study of possibilities to increase the efficiency of multilevel power converters (MPE) for reactive power compensation (RPC) in local electrical networks (LES) on the basis of plenipotentiary controlled semiconductor cells is of particular interest, because the efficiency of network operation is insufficient, especially in changing load modes with large electric power losses (PEM). And from these positions, one of the most effective tools are fast controlled (PFC) systems. For this purpose, research has been carried out to obtain the best results. Used in calculations tool and methodology are certified software products and algorithms of ABB-SEMIS Simulation Tool computer design.

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A Divya Teja and Dr. N Sambasiva Rao. "Analysis of Three Phase 3-Level NPC Voltage Source Converter for AC-DC Conversion." International Journal for Modern Trends in Science and Technology 06, no. 09 (November 25, 2020): 144–48. http://dx.doi.org/10.46501/ijmtst060922.

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The use of power electronic converters influences the generation of harmonics and reactive power flow in power system. Therefore, three-phase multilevel improved power quality AC-DC converters are gaining lot of popularity in power conversion applications. This work deals with critical problem of multilevel structure i.e neutral point potential (NPP) variation. In this paper, a simplified current controlled scheme is presented to ensure unity power factor operation. Neutral point potential (NPP) of three-phase, 3-level NPC AC-DC converter is controlled by modifying control signal in the controller using NPP regulator. An auxiliary circuit is being presented in this paper as an alternative option for controlling the neutral point potential of the converter. Comparison has been carried out between these control techniques in terms of power quality. A complete mathematical model is presented for better understanding of both techniques used for NPP control. The presented control techniques has been verified through simulation investigations and validated

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Ali, Muhammad, Ajmal Farooq, Muhammad Qasim Khan, Muhammad Mansoor Khan, and Lucian Mihet-Popa. "Analysis of Asymmetric Hybrid Modular Multilevel Topology for Medium-Voltage Front-End Converter Applications." Energies 16, no. 4 (February 4, 2023): 1572. http://dx.doi.org/10.3390/en16041572.

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Modular multilevel converters (MMCs) have been conceived as an alternative in front-end converter applications to enhance the converter system’s reliability, minimize total harmonic distortion, and improve power quality. These converters utilize several DC-link capacitors and power electronic switches, along with switches operating with high switching frequencies, to attain the desired characteristics. Thereby, this paper systematically proposes a novel three-phase asymmetric hybrid modular multilevel converter (AHMMC) for front-end converters used in lower-medium-voltage applications. The AHMMC configuration is based on a three-phase converter connected to a per-phase series arrangement with a cascaded converter module (CCM). The study investigates the AHMMC and proposes a control scheme, which minimizes the voltage range on switches and maintains the current to its reference value. Furthermore, the study also introduces an active balancing of voltage across DC-link capacitors based on the phase opposition disposition PWM (POD-PWM) method. Our new configuration has features such as low switching loss, reduced DC-link voltage, a wider modulation range for the unity power factor (PF), and low voltage and current harmonic distortion. The simulation results are added to verify the performance of the new AHMMC topology and the usefulness of the modular control scheme. In addition, a low-voltage laboratory prototype based on customized control and power boards is built to validate the proposed converter and its control scheme in practice.

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Zanasi, Roberto, and Davide Tebaldi. "Modeling Control and Robustness Assessment of Multilevel Flying-Capacitor Converters." Energies 14, no. 7 (March 30, 2021): 1903. http://dx.doi.org/10.3390/en14071903.

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When performing AC/DC-DC/AC power conversions, multilevel converters provide several advantages as compared to classical two-level converters. This paper deals with the dynamic modeling, control, and robustness assessment of multilevel flying-capacitor converters. The dynamic model is derived using the Power-Oriented Graphs modeling technique, which provides the user with block schemes that are directly implementable in the Matlab/Simulink environment by employing standard Simulink libraries. The performed robustness assessment has led to the proposal of a divergence index, which allows for evaluating the voltage balancing capability of the converter using different voltage vector configurations for the extended operation of the converter, namely when the number of output voltage levels is increased for a given number of capacitors. A new variable-step control algorithm is then proposed. The variable-step control algorithm safely enables the converter extended operation, which prevents voltage balancing issues, even under particularly unfavorable conditions, such as a constant desired output voltage or a sudden load change. The simulation results showing the good performances of the proposed variable-step control as compared to a classical minimum distance approach are finally provided and commented in detail.

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23

Domino, A., K. Zymmer, and M. Parchomiuk. "Selected converter topologies for interfacing energy storages with power grid." Bulletin of the Polish Academy of Sciences Technical Sciences 65, no. 5 (October 1, 2017): 579–88. http://dx.doi.org/10.1515/bpasts-2017-0063.

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Abstract The paper presents different solutions applicable in power converter systems for connecting power grids with energy storage systems such as superconducting magnetic energy storage (SMES), supercapacitor energy storage (SES) or chemical batteries. Those systems are characterized by bidirectional current flow between energy storage and power grid. Two-level converters (AC-DC and DC-AC converters) dedicated for low power energy storage compatible with 3×400 V-type power grids are proposed. High power systems are connected with 3×6 kV-type power grids via transformers that adjust voltage to the particular energy storage or directly, based on multilevel power converters (AC-DC and DC-AC) or dual active bridge (DAB) systems. Solutions ensuring power grid compatibility with several energy storage systems of the same electrical parameters as well as of different voltage-current characteristics are also proposed. Selected simulation results illustrating operation of two system topologies of 200 kW power for two-level converter and neutral point clamped (NPC) three-level converter are presented.

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Erat, Abdurrahim, and Ahmet Mete Vural. "DC/DC Modular Multilevel Converters for HVDC Interconnection: A Comprehensive Review." International Transactions on Electrical Energy Systems 2022 (September 8, 2022): 1–49. http://dx.doi.org/10.1155/2022/2687243.

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Анотація:

High voltage direct current (HVDC) technology is a key component in power systems owing to huge benefits such as long-distance power transmission, lower losses, asynchronous grid interconnections, controllability, system availability, and limited short-circuit currents. HVDC transmission is a cost-effective method of transporting huge amounts of power across long distances with little loss. It can also link asynchronous alternative current (AC) networks while balancing the grid. DC/DC converters are one of the most important components for HVDC power transmission, and DC/DC modular multilevel converters (MMCs) are the backbone of HVDC grid interconnections. The DC/DC MMC is a highly regarded converter architecture for medium/high-voltage DC grid interconnection. DC/DC MMC topologies play a key role in modern HVDC networks with varying voltage levels. This paper’s fundamental aim is to offer a recent comprehensive review of HVDC topologies, current DC/DC modular multilevel converter (MMC) topologies for HVDC interconnection, and DC/DC MMC control techniques.

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25

Diab, Ahmed A. Zaki, Terad Ebraheem, Raseel Aljendy, Hamdy M. Sultan, and Ziad M. Ali. "Optimal Design and Control of MMC STATCOM for Improving Power Quality Indicators." Applied Sciences 10, no. 7 (April 4, 2020): 2490. http://dx.doi.org/10.3390/app10072490.

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Анотація:

In recent years, modular multilevel converters (MMC) are becoming popular in the distribution and transmission of electrical systems. The multilevel converter suffers from circulating current within the converter that increases the conduction loss of switches and increases the thermal stress on the capacitors and switches’ IGBTs. One of the main solutions to control the circulating current is to keep the capacitor voltage balanced in the MMC. In this paper, a new hybrid control algorithm for the cascaded modular multilevel converter is presented. The Harris hawk’s optimization (HHO) and Atom search optimization (ASO) are used to optimally design the controller of the hybrid MMC. The proposed structure of modular multilevel inverters allows effective operation, a low level of harmonic distortion in the absence of output voltage filters, a low switching frequency, and excellent flexibility to achieve the requirements of any voltage level. The effectiveness of the proposed controller and the multilevel converter has been verified through testing with the application of the MMC-static synchronous compensator (STATCOM). The stability of the voltage capacitors was monitored with balanced and unbalanced loads on the studied network.

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26

Ali, Salman, Santiago Bogarra, Muhammad Mansooor Khan, Ahmad Taha, Pyae Pyae Phyo, and Yung-Cheol Byun. "Prospective Submodule Topologies for MMC-BESS and Its Control Analysis with HBSM." Electronics 12, no. 1 (December 21, 2022): 20. http://dx.doi.org/10.3390/electronics12010020.

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Анотація:

Battery energy storage systems and multilevel converters are the most essential constituents of modern medium voltage networks. In this regard, the modular multilevel converter offers numerous advantages over other multilevel converters. The key feature of modular multilevel converter is its capability to integrate small battery packs in a split manner, given the opportunity to submodules to operate at considerably low voltages. In this paper, we focus on study of potential SMs for modular multilevel converter based battery energy storage system while, keeping in view the inconsistency of secondary batteries. Although, selecting a submodule for modular multilevel converter based battery energy storage system, the state of charge control complexity is a key concern, which increases as the voltage levels increase. This study suggests that the half-bridge, clamped single, and full-bridge submodules are the most suitable submodules for modular multilevel converter based battery energy storage system since, they provide simplest state of charge control due to integration of one battery pack along with other advantages among all 24 submodule topologies. Depending on submodules analysis, the modular multilevel converter based battery energy storage system based on half-bridge submodules is investigated by splitting it into AC and DC equivalent circuits to acquire the AC and DC side power controls along with an state of charge control. Subsequently, to validate different control modes, a downscaled laboratory prototype has been developed.

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27

Sadikin, Muhammad, Tomonobu Senjyu, and Atsushi Yona. "DC–DC Type High-Frequency Link DC for Improved Power Quality of Cascaded Multilevel Inverter." International Journal of Emerging Electric Power Systems 14, no. 4 (June 28, 2013): 333–40. http://dx.doi.org/10.1515/ijeeps-2012-0007.

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Abstract Multilevel inverters are emerging as a new breed of power converter options for power system applications. Recent advances in power switching devices enabled the suitability of multilevel inverters for high voltage and high power applications because they are connecting several devices in series without the need of component matching. Usually, a transformerless battery energy storage system, based on a cascaded multilevel inverter, is used as a measure for voltage and frequency deviations. System can be reduced in size, weight, and cost of energy storage system. High-frequency link circuit topology is advantageous in realizing compact and light-weight power converters for uninterruptible power supply systems, new energy systems using photovoltaic-cells, fuel-cells and so on. This paper presents a DC–DC type high-frequency link DC (HFLDC) cascaded multilevel inverter. Each converter cell is implemented a control strategy for two H-bridge inverters that are controlled with the same multicarrier pulse width modulation (PWM) technique. The proposed cascaded multilevel inverter generates lower voltage total harmonic distortion (THD) in comparison with conventional cascaded multilevel inverter. Digital simulations are carried out using PSCAD/EMTDC to validate the performance of the proposed cascaded multilevel inverter.

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28

Hassan, Raaed Faleh, and Suha Sabah Shyaa. "Design and Analysis of the STATCOM Based on Diode Clamped Multilevel Converter Using Model Predictive Current Control Strategy." European Journal of Electrical Engineering 23, no. 3 (June 21, 2021): 221–28. http://dx.doi.org/10.18280/ejee.230306.

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Анотація:

In recent decades, multi-level converters have become popular and used in many power systems applications. Compared with conventional converters, multi-level converters contribute to reducing the voltage stress on the switching devices and enhancing the power quality delivered to the load. In this paper, the study of the five-level diode clamped multilevel converter based static synchronous compensator has been accomplished. Model Predictive current control strategy which a type of modern control algorithms was employed for driving the proposed compensator. The suggested five level converter controlled by model predictive current control is firstly examined to verify that this control algorithm is appropriate for achieving the desired performance. Then the proposed converter and control combination is employed and simulated as a static synchronous compensator in distributed power system. Moreover, in order to examine the robustness of this compensator, the load status is suggested to be heavy inductive. Simulation process has been performed using MATLAB – SIMULINK software package. The results show that the implemented configuration (converter and control algorithm) provides high power quality improvement with adequate reactive power compensation.

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29

Shahbaz, Muhammad Hamza, Kashif Amjad, Naqash Ahmad, Arslan Ahmed Amin, Sajid Iqbal, Muhammad Gufran Khan, and Muhammad Adnan. "A streamlined 17-level cascaded H-bridge multilevel converter with solar PV integration." Bulletin of Electrical Engineering and Informatics 10, no. 2 (April 1, 2021): 598–608. http://dx.doi.org/10.11591/eei.v10i2.2764.

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Анотація:

The quest for a green electrical power system has increased the use of renewable energy resources and power electronic converters in the existing power system. These power electronic converters, however, are a major cause of harmonics and result in the degradation of power quality. In the last two decades, researchers have proposed various designs of multilevel converters to minimize these harmonic distortions, however, a comprehensive solution for stand-alone solar photovoltaic (PV) systems with low total harmonic distortion (THD) is still missing in the present body of knowledge. This paper proposes a single-phase 17-level cascaded H-bridge multilevel converter (CHMC) model for a stand-alone system using solar PV arrays. The proposed model employs eight different flexible PV arrays that can be replaced with DC voltage sources when required to meet the load demand. The proposed model does not include any capacitor and filter thus saving a lot of cost in the overall system. The model has been implemented in the Simulink environment using a model-based design approach. The simulation results show that the proposed model has reduced the THD to almost 7% as compared to the existing models. The cost comparison of the proposed converter also proved its economic benefit over other types.

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30

Quester, Matthias, Fisnik Loku, Otmane El Azzati, Leonel Noris, Yongtao Yang, and Albert Moser. "Investigating the Converter-Driven Stability of an Offshore HVDC System." Energies 14, no. 8 (April 20, 2021): 2341. http://dx.doi.org/10.3390/en14082341.

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Анотація:

Offshore wind farms are increasingly built in the North Sea and the number of HVDC systems transmitting the wind power to shore increases as well. To connect offshore wind farms to adjacent AC transmission systems, onshore and offshore modular multilevel converters transform the transmitted power from AC to DC and vice versa. Additionally, modern wind farms mainly use wind turbines connected to the offshore point of common coupling via voltage source converters. However, converters and their control systems can cause unwanted interactions, referred to as converter-driven stability problems. The resulting instabilities can be predicted by applying an impedance-based analysis in the frequency domain. Considering that the converter models and system data are often confidential and cannot be exchanged in real systems, this paper proposes an enhanced impedance measurement method suitable for black-box applications to investigate the interactions. A frequency response analysis identifies coupling currents depending on the control system. The currents are subsequently added to the impedance models to achieve higher accuracy. The proposed method is applied to assess an offshore HVDC system’s converter-driven stability, using impedance measurements of laboratory converters and a wind turbine converter controller replica. The results show that the onshore modular multilevel converter interacts with AC grids of moderate short-circuit ratios. However, no interactions are identified between the offshore converter and the connected wind farm.

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31

Alatai, Salah, Mohamed Salem, Dahaman Ishak, Himadry Shekhar Das, Mohammad Alhuyi Nazari, Ali Bughneda, and Mohamad Kamarol. "A Review on State-of-the-Art Power Converters: Bidirectional, Resonant, Multilevel Converters and Their Derivatives." Applied Sciences 11, no. 21 (October 29, 2021): 10172. http://dx.doi.org/10.3390/app112110172.

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Анотація:

With the rapid development of modern energy applications such as renewable energy, PV systems, electric vehicles, and smart grids, DC-DC converters have become the key component to meet strict industrial demands. More advanced converters are effective in minimizing switching losses and providing an efficient energy conversion; nonetheless, the main challenge is to provide a single converter that has all the required features to deliver efficient energy for different types of modern energy systems and energy storage system integrations. This paper reviews multilevel, bidirectional, and resonant converters with respect to their constructions, classifications, merits, demerits, combined topologies, applications, and challenges; practical recommendations were also made to deliver clear ideas of the recent challenges and limited capabilities of these three converters to guide society on improving and providing a new, efficient, and economic converter that meets the strict demands of modern energy system integrations. The needs of other industrial applications, as well as the number of used elements for size and weight reduction, were also considered to achieve a power circuit that can effectively address the identified limitations. In brief, integrated bidirectional resonant DC-DC converters and multilevel inverters are expected to be well suited and highly demanded in various applications in the near future. Due to their highlighted merits, more studies are necessary for achieving a perfect level of reducing losses and components.

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32

Malinowski, M. "Cascaded multilevel converters in recent research and applications." Bulletin of the Polish Academy of Sciences Technical Sciences 65, no. 5 (October 1, 2017): 567–78. http://dx.doi.org/10.1515/bpasts-2017-0062.

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Abstract Multilevel converters have been intensively investigated and developed since 1960s and have found successful industrial applications. The aim of this paper is to present state of the art as well as recent research and applications of cascaded multilevel converters, which are a very interesting solution for power distribution systems and renewable energy sources. Cascaded multilevel converters can easily operate at medium and high voltage based on the series connection of power modules (cells), which use standard low-voltage component configurations. Series connections of modules (cells) allow for high quality output voltages and input currents, reduction of passive components and availability of component redundancy. Due to these features the cascaded multilevel converters have been recognized as attractive solutions for high-voltage direct-current (HVDC) transmission, solid state transformers (SST) and photovoltaic (PV) systems.

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33

Zhang, Jianzhong, Shuai Xu, Zakiud Din, and Xing Hu. "Hybrid Multilevel Converters: Topologies, Evolutions and Verifications." Energies 12, no. 4 (February 15, 2019): 615. http://dx.doi.org/10.3390/en12040615.

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Анотація:

Multilevel converters have good potential in high power and high voltage applications due to their advantages of reduced voltage or current stress on power devices. In recent years, hybrid multilevel converter (HMC) have attracted increasing attention since less equipment is required. In this paper, the topologies and evolutions of HMCs are presented, where five topology derivation ways are given by using basic cells in series-parallel/parallel-series. Some general topologies or structures that are used to generate higher levels are also deducted. Then many existing HMCs can be derived, and new topologies of the HMC might be inspired. The capabilities of neutral point and FC voltage balancing control are investigated. The performance of the selected FC-based HMCs is analyzed. Finally, the verifications of operation principle and control strategies for the derived HMCs are carried out.

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34

Stepanov, A., L. Biesenieks, A. Sokolovs, and I. Galkin. "Development of a Modular Power Converter." Scientific Journal of Riga Technical University. Power and Electrical Engineering 25, no. 25 (January 1, 2009): 113–16. http://dx.doi.org/10.2478/v10144-009-0024-0.

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Development of a Modular Power ConverterThis report describes the most important details of elaboration of a versatile power module that can be utilized as a part of various converters. Two or more modules connected together can form a frequency converter or multilevel converter or 3-phase inverter/rectifier etc. Initially the module was developed for fast prototyping of uninterruptible power supplies and energy systems with alternative energy sources. The module can be used also as a basis for laboratory equipment of the power electronics course.

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35

Schaef, Christopher, and Jason T. Stauth. "Multilevel Power Point Tracking for Partial Power Processing Photovoltaic Converters." IEEE Journal of Emerging and Selected Topics in Power Electronics 2, no. 4 (December 2014): 859–69. http://dx.doi.org/10.1109/jestpe.2014.2332952.

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36

Nazemi, Adel, Omid Salari, Mohammad Tavakoli Bina, Masoud Kazemi, and Bahman Eskandari. "Predictive Control for Reduced Structure Multilevel Converters: Experimenting on a Seven Level Packed U-Cell." International Journal of Power Electronics and Drive Systems (IJPEDS) 7, no. 2 (June 1, 2016): 568. http://dx.doi.org/10.11591/ijpeds.v7.i2.pp568-582.

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Анотація:

Recently, a branch of multilevel converters is emerged, in which their ‘reduced structure’ topologies use lower number of devices compared to the available topologies. To get a cost efficient converter, lower number of components as well as high quality waveforms, multilevel converters with a ‘reduced structure’ (MCRS) are suitable for high/medium power systems. Also, utilizing the fast microprocessors available today, applications of predictive control in power converters are of very powerful and attractive alternatives to classical controllers. This paper proposes a finite control set model-based predictive control (FCS-MPC) for load current regulation and capacitor voltage balancing for a typical MCRS. A case study considered, three-phase seven level packed U-cell (PUC), which is among reduced structure multilevel converters. A discrete model of the system is derived, and a predictive model-based control is developed according to this model in order to predict the future behavior of the system for all possible switching states; then, the switching state that optimized the cost function is selected. The feasibility of the proposed FCS-MPC strategy for a seven level PUC is evaluated based on simulations with MATLAB/ SIMULINK. Moreover, experimental validation of the proposed control system on a 5 kVA PUC is examined through DSP implementation.

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37

Richard, Pierre-Yves, Hervé Cormerais, Cécile Morvan, and Jean Buisson. "BOOLEAN SLIDING MODE CONTROL OF MULTILEVEL POWER CONVERTERS." IFAC Proceedings Volumes 38, no. 1 (2005): 424–29. http://dx.doi.org/10.3182/20050703-6-cz-1902.01799.

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38

Peftitsis, D., G. Tolstoy, A. Antonopoulos, J. Rabkowski, Jang-Kwon Lim, M. Bakowski, Lennart Ängquist, and H. Nee. "High-Power Modular Multilevel Converters With SiC JFETs." IEEE Transactions on Power Electronics 27, no. 1 (January 2012): 28–36. http://dx.doi.org/10.1109/tpel.2011.2155671.

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39

Rodriguez, F. J., C. Giron, E. J. Bueno, A. Hernandez, S. Cobreces, and P. Martin. "Remote Laboratory for Experimentation With Multilevel Power Converters." IEEE Transactions on Industrial Electronics 56, no. 7 (July 2009): 2450–63. http://dx.doi.org/10.1109/tie.2009.2017493.

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40

Kim, Jintae, Sotirios Limotyrakis, and Chih-Kong Ken Yang. "Multilevel Power Optimization of Pipelined A/D Converters." IEEE Transactions on Very Large Scale Integration (VLSI) Systems 19, no. 5 (May 2011): 832–45. http://dx.doi.org/10.1109/tvlsi.2010.2041077.

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41

M, Geetha, Palaniswami Dr.S., and Suresh Dr.S. "Cascaded Multilevel Converters for Statcom – An Approach for Mitigation of Power Quality Indices." Journal of Advanced Research in Dynamical and Control Systems 11, no. 11-SPECIAL ISSUE (November 20, 2019): 1218–24. http://dx.doi.org/10.5373/jardcs/v11sp11/20193155.

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42

Gontijo, Gustavo, Songda Wang, Tamas Kerekes, and Remus Teodorescu. "Performance Analysis of Modular Multilevel Converter and Modular Multilevel Series Converter under Variable-Frequency Operation Regarding Submodule-Capacitor Voltage Ripple." Energies 14, no. 3 (February 2, 2021): 776. http://dx.doi.org/10.3390/en14030776.

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Анотація:

The modular multilevel converter is capable to reach high-voltage levels with high flexibility, high reliability, and high power quality as it became the standard solution for high-power high-voltage applications that operate with fixed frequency. However, in machine-drive applications, the modular multilevel converter shows critical problems since an extremely high submodule-capacitor voltage ripple occurs in the machine start-up and at low-speed operation, which can damage the converter. Recently, a new converter solution named modular multilevel series converter was proposed as a promising alternative for high-power machine-drive applications since it presented many important structural and operational advantages in relation to the modular multilevel converter such as the reduced number of submodule capacitors and the low submodule-capacitor voltage ripple at low frequencies. Even though the modular multilevel series converter presented a reduced number of capacitors, the size of these capacitors was not analyzed. This paper presents a detailed comparison analysis of the performance of the modular multilevel converter and the modular multilevel series converter at variable-frequency operation, which is based on the proposed analytical description of the submodule-capacitor voltage ripple in such topologies. This analysis concludes that the new modular multilevel series converter can be designed with smaller capacitors in comparison to the modular multilevel converter if these converters are used to drive electrical machines that operate within a range of low-frequency values. In other words, the modular multilevel series converter experiences extremely low submodule-capacitor voltage ripple at very low frequencies, which means that this converter solution presents high performance in the electrical machine start-up and at low-speed operation.

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43

Hu, Jinxuan, Gang Yao, and Lidan Zhou. "Control and Study of the Three-Phase Three-Level Dual Active Bridge DC Converter." Journal of Physics: Conference Series 2477, no. 1 (April 1, 2023): 012087. http://dx.doi.org/10.1088/1742-6596/2477/1/012087.

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Abstract Multilevel DAB converters can share more effectively the reverse voltage compared to conventional dual active full-bridge converters, reducing the cost of switching tubes at the same power and voltage levels. At the same time, the increased control freedom of multilevel makes the control objectives more flexible, combining optimization objectives such as soft switching and inductor current reduction. In this paper, we propose a three-phase three-level dual active converter, based on the power transfer characteristics of dual phase shift control in the time domain, deriving the effect of inductor current with phase shift angle and variable voltage ratio, and determining the conditions for the switching tubes to work in soft switching, which effectively reduces the DC bus current fluctuation. Finally, the correctness of the theoretical analysis is verified by simulation.

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44

Choi, Z. H., C. L. Toh, and M. H. Z. Hilmi. "Comparative study of two potential recuperating converters in DC railway electrification system for harmonic mitigation." International Journal of Power Electronics and Drive Systems (IJPEDS) 10, no. 3 (September 1, 2019): 1157. http://dx.doi.org/10.11591/ijpeds.v10.i3.pp1157-1166.

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Анотація:

The regenerative braking energy produced by Light-Rail-Transit (LRT) train is commonly transferred back to power grid via a conventional three-phase inverter (recuperating converter). Although this is a cost saving solution but the ac grid current and voltage waveforms were distorted. Hence passive filters are integrated to mitigate the harmonics. This paper proposed to replace the conventional inverter system with a multilevel converter. Cascaded H-Bridge (CHB) converter and Modular Multilevel Converter (MMC) are selected to be evaluated in this paper due to their modularity structures. The aim of this study is to determine the most potential multilevel converter to be implemented without additional passive filters. Nine-level CHB and nine-level MMC converters are modeled with MATLAB/Simulink simulation tool. Both converters are modulated with Level-Shifted Pulse Width Modulation technique. The output voltage and current waveforms generated by CHB and MMC are presented with full analysis. It is concluded that MMC converter is more suitable to be used as a recuperating converter. It produces a clean voltage and current waveforms. The voltage and current Total Harmonic Distortion (THD) indexes are found approximate to 8% and 3%.

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Barcellona, Simone, Marzio Barresi, and Luigi Piegari. "MMC-Based PV Single-Phase System with Distributed MPPT." Energies 13, no. 15 (August 1, 2020): 3964. http://dx.doi.org/10.3390/en13153964.

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Анотація:

The presence and evolution of static power converters in electric grids are growing on a daily basis. Starting from the most used voltage source converter (VSC), passing through the use of multilevel converters, the most recent configuration is the so-called modular multilevel converter (MMC). Because of its intrinsic advantages, it is used not only in high-voltage systems but also in low- and medium-voltage ones to interface renewable energy sources such as photovoltaic (PV) panels. Several configurations and maximum power point tracker (MPPT) algorithms have been proposed and analyzed for MMC-PV-based systems. However, when using distributed MPPTs, partial shading conditions cause a problem. The PV panel can be directly connected to the MMC using its dc link or submodule. Based on this configuration, this paper proposes a novel control strategy that tracks both the ac grid current and ac circulating current for a single-phase low-voltage system to obtain the maximum power under any irradiance condition. The effectiveness of the proposed control strategy is demonstrated through time-domain simulation results.

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46

Yahiaoui, Abdelhalim, Koussaila Iffouzar, Kaci Ghedamsi, and Kamal Himour. "Dynamic Performance Analysis of VSC-HVDC Based Modular Multilevel Converter under Fault." Journal Européen des Systèmes Automatisés 54, no. 1 (February 28, 2021): 187–94. http://dx.doi.org/10.18280/jesa.540121.

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Анотація:

The use of high voltage direct current based voltage source converter (VSC-HVDC) in power transmission systems knows a great progress in recent years. Above all, with the new generation of power electronics converters such as the modular multi-level converter (MMC), with his scalable structure it can theoretically meet any voltage level requirement, which allows to increase the size of the power transferred compared to conventional converters. In this sense, this paper presents a study of a VSC-HVDC system based on a modular multi-level converter (MMC). The main objective of this work is to analyze the performance of the VSC-HVDC system based MMC without the AC filters and its control in the event of a fault, during set point changes and unbalanced grid conditions. After realization a mathematical model of the system studied and its control, simulations are done over in Simpower System/Matlab. The results obtained confirm the robustness of the system control and the system gives a good energy quality, that manifests by a good output currant and voltage curves with no need to use a voluminous AC filter.

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47

Leite, Rafael, João Afonso, and Vítor Monteiro. "A Novel Multilevel Bidirectional Topology for On-Board EV Battery Chargers in Smart Grids." Energies 11, no. 12 (December 10, 2018): 3453. http://dx.doi.org/10.3390/en11123453.

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This paper proposes a novel on-board electric vehicle (EV) battery charger (EVBC) based on a bidirectional multilevel topology. The proposed topology is formed by an AC-DC converter for the grid-side interface and by a DC-DC converter for the battery-side interface. Both converters are interfaced by a split DC-link used to achieve distinct voltage levels in both converters. Characteristically, the proposed EVBC operates with sinusoidal grid-side current, unitary power factor, controlled battery-side current or voltage, and controlled DC-link voltages. The grid-side converter operates with five voltage levels, while the battery-side operates with three voltage levels. An assessment, for comparison with classical multilevel converters for EVBCs is considered along the paper, illustrating the key benefits of the proposed topology. As the proposed EVBC is controlled in bidirectional mode, targeting the EV incorporation into smart grids, the grid-to-vehicle (G2V) and vehicle-to-grid (V2G) operation modes are discussed and evaluated. Both converters of the proposed EVBC use discrete-time predictive control algorithms, which are described in the paper. An experimental validation was performed under real operating conditions, employing a developed laboratory prototype.

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48

Zhang, Xinlin, Yanchi Zhang, Da Xie, and Bowen Zhao. "Study of start-up decoupling controller for modular multilevel converter." E3S Web of Conferences 261 (2021): 01026. http://dx.doi.org/10.1051/e3sconf/202126101026.

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Анотація:

Modular multilevel converters are widely used in power systems because of their significant advantages. In this paper, a dynamic mathematical model is established by analyzing the topology, operating principle and switching function of the modular multilevel converter, so as to construct an inner and outer loop decoupling controller in dq coordinates. The carrier phase-shift pulse-width modulation is selected to control the sub-module operation, and the uncontrolled pre-charging method is adopted to charge the sub-module. Finally, simulation experiments are carried out in MATLAB/Simulink, and the results show that the control method achieves smooth start-up of the modular multilevel converter.

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49

Wu, Hao, and Ping Wang. "A Novel Modulation Method for Modular Multilevel Converters." Applied Mechanics and Materials 538 (April 2014): 239–42. http://dx.doi.org/10.4028/www.scientific.net/amm.538.239.

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Анотація:

Modular Multilevel has been widely applied in Flexible HVDC, electric locomotives and PET(Power Electronics Transformers). The modulation method is important for the converter performance. This paper presents an improved modulation method for Modular Multilevel Converter.

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50

Triefena, Laras, Leonardus H. Pratomo, Slamet Riyadi, and F. Budi Setiawan. "Design and Implementation of Boost Voltage Doubler for Maximum Power Point Tracker Application Using STM32F1038CT." JURNAL INFOTEL 12, no. 4 (November 25, 2020): 134–40. http://dx.doi.org/10.20895/infotel.v12i4.545.

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Анотація:

Photovoltaic is an absolute device in the solar power plant system. A DC-DC converter with a maximum power point tracker (MPPT) algorithm is required to obtain the maximum power of photovoltaic. In general, solar power plant applications used a two-stage converter: the first stage is boosting DC-DC converter, and the second stage is the multilevel Inverter. Boost DC-DC converter is usually implemented singly, which causes many boost DC-DC converters to be implemented in a solar power plant application. The voltage doubler type boost DC-DC converter proposed in this paper is to simplify the circuit so that there is only one converter in a solar power plant application. This converter principle combines two conventional boost converters, which are integrated into one so that the power circuit and control circuit form become simpler. This proposal is verified through computation simulation and hardware design using the STM32F1038CT microcontroller for the final verification. The efficiency algorithm of the simulation is 99.7%, and the hardware experimental is 85.65%

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Статті в журналах з теми "Multilevel Power Converters"

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