Modeling and simulation of a MMC-based solid-state transformer

Adabi, M. Ebrahim; Martínez-Velasco, Juan A.; Alepuz, Salvador

doi:10.1007/s00202-017-0510-x

Cited by 8 publications

(4 citation statements)

References 41 publications

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“…Figure 15 shows the voltages and currents of the MVDC and buss in all modules (UMVDC, IMVDC), and Figure 16 shows the voltage, current, and power of the common LVDC bus (ULVDC, ILVDC, PLVDC). Furthermore, an evaluation of the power factor (PF), total system efficiency (ɳ ), and total harmonic distortion of current (THDi) was taken into account in this paper; see (18)(19)(20). Figures 14-16 show the main parameters of the investigated ET concept, i.e., Figure 14 shows the voltages, currents and the active and reactive power of the MVAC grid (U MVAC , I MVAC , P MVAC , Q MVAC ).…”

Section: Resultsmentioning

confidence: 99%

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Global Simulation Model Design of Input-Serial, Output-Parallel Solid-State Transformer for Smart Grid Applications

et al. 2023

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This paper provides an overview of an early attempt at developing a simulation model on a solid-state transformer (SST) based on input-serial and output-parallel (ISOP) topology. The proposed SST is designed as a base for a smart grid (SG). The paper provides a theoretical review of the power converters under consideration, as well as their control techniques. Further, the paper presents a simulation model of the proposed concept with a PLECS circuit simulator. The proposed simulation model examines bidirectional energy flow control between the medium-voltage AC grid and DC smart grid, while evaluating power flow efficiency and qualitative indicators of the AC grid. After the completion of design verification and electrical properties analysis by the PLECS simulation models, the synthesis offers recommendations on the optimal layout of the proposed SST topology for smart grid application.

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Section: Resultsmentioning

confidence: 99%

“…It is necessary to compensate the voltage drops across filters to ensure the proper operation of the MMCHB converter [18]. This can be achieved by calculating the DC output voltage (V mvdc ) with an added tolerance.…”

Section: 𝑉 𝑉mentioning

confidence: 99%

Global Simulation Model Design of Input-Serial, Output-Parallel Solid-State Transformer for Smart Grid Applications

et al. 2023

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“…As a result, the use of multi-level converters has more advantages in the MV side such as modularity, a smaller passive filter, higher reliability, and fault-tolerant capability. Examples of multi-level converters used in the MV side of SST are NPC [134], FC [135], CHB [136], and MMC [137,138]. Figure 8 shows the different possible topologies of SST according to the input/output connection of power electronic converters.…”

Section: Ssts Classificationmentioning

confidence: 99%

Review of Solid-State Transformer Applications on Electric Vehicle DC Ultra-Fast Charging Station

2022

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The emergence of DC fast chargers for electric vehicle batteries (EVBs) has prompted the design of ad-hoc microgrids (MGs), in which the use of a solid-state transformer (SST) instead of a low-frequency service transformer can increase the efficiency and reduce the volume and weight of the MG electrical architecture. Mimicking a conventional gasoline station in terms of service duration and service simultaneity to several customers has led to the notion of ultra-fast chargers, in which the charging time is less than 10 min and the MG power is higher than 350 kW. This survey reviews the state-of-the-art of DC ultra-fast charging stations, SST transformers, and DC ultra-fast charging stations based on SST. Ultra-fast charging definition and its requirements are analyzed, and SST characteristics and applications together with the configuration of power electronic converters in SST-based ultra-fast charging stations are described. A new classification of topologies for DC SST-based ultra-fast charging stations is proposed considering input power, delta/wye connections, number of output ports, and power electronic converters. More than 250 published papers from the recent literature have been reviewed to identify the common understandings, practical implementation challenges, and research opportunities in the application of DC ultra-fast charging in EVs. In particular, the works published over the last three years about SST-based DC ultra-fast charging have been reviewed.

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“…Figure 1.1 shows four basic topology configurations, namely types A, B, C, and D, which can suit SST functions [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15], [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16].…”

Section: The Sst Definition and Organizationmentioning

confidence: 99%

Advanced modeling of solid state transformer

Adabi Firouzjaee

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The solid state transformer (SST) is seen as a proper replacement of the conventional iron-and-copper transformer in the future smart grid . The SST offers several benefits (e.g. enhanced power quality performance or reactive power control at both primary and secondary sides) that can be of paramount importance for the development of the smart grid . This research focuses on the development and implementation of an advanced model of a three stage bidirectional SST in Matlab/Simulink. The goal is to obtain an realistic SST model (i.e. as close to the real SST as possible) that could duplicate the performance of a real MV/LV SST. This considered design consists of three main stages: medium voltage (MV) stage, isolation stage, and low voltage (LV) stage. When the power flows from the MV side to the LV side, the input power-frequency ac voltage is converted into a MV dc voltage by the three-phase ac/dc converter, which in such case works as rectifier. The isolation stage, which includes a high-frequency transformer (HFT) and the two corresponding MV- and LV-side converters, first converts the MV-side dc voltage into a high-frequency square-wave voltage applied to the primary of the HFT; the secondary side square-wave signal is then converted to a LV dc waveform by the LV-side converter, which also works as rectifier. Finally, the output LV-side three-phase dc/ac converter, which works as inverter, provides the output power-frequency ac waveform from the LV-side dc link. Si-based semiconductor technologies can be used for MV applications using a multilelvel configuration. Recently, modular multilevel converter (MMC) topologies have attracted attention for high or medium voltage applications. These converters can provide an effective topology for the MV side of the SST; their main advantages are modularity and scalability: the desired voltage level can be easily achieved by a series connection of MMC sub-modules (SMs). In addition,a MMC topology can provide high power quality and efficiency with reduced size of passive filters. These features made the MMC option an attractive topology for the MV stage of the SST. This thesis proposes a three-stage SST configuration based on MMC technology for MV converters. * The input stage of the SST is connected to the distribution system via RL filters and its three-phase configuration uses a MMC technology. A half-bridge configuration is proposed for each SM. * The isolation stage consists of three parts: a MV single-phase MMC, the high-frequency transformer (HFT), and a single-phase LV PWM converter. * The LV side of the SST uses a three-phase four-leg PWM converter, with an RL impedance for filtering currents and a capacitor bank for filtering voltages. The converters and their controller have been implemented adn tested considering models without and with semiconductor losses, while the SST model has been tested as a stand-alone device and a compnent of a distribution system. The model has been tested under severe dynamic and unbalanced conditions. The simulation results support the choices made for any SST stage and proves that the proposed design could be a feasible choice for the future SST. El Transformador de Estado Sólido ("Solid State Transformer" por sus siglas en inglés) es visto como un reemplazo adecuado del transformador convencional en las futuras redes inteligentes (smart grids ). Este nuevo dispositivo presenta una amplia gama de prestaciones (p.e. mejora de la cualidad de suministro) que pueden ser de crucial importancia para el desarrollo de las redes inteligentes. El principal objetivo de esta tesis es que desarrollar e implantar el en Matlab/Simulink un modelo realista de estado sólido trifásico y bidireccional, que pueda duplicar el comportamiento de un transformador de estado sólido de Media-Baja tensión. El diseño considerado consiste en tres etapas: etapa en media tensión (MT), etapa intermedia, etapa en baja tensión (BT). Cuando la potencia fluye del terminal en media al terminal en baja tensión, la tensión alterna en el terminal de entrada a media tensión y frecuencia de operación 50 Hz se convierte en continua a media tensión mediante un convertidor trifásico rectificador. La etapa intermedia es un puente activo dual, que incluye un transformador de alta frecuencia y los correspondientes convertidores en media y baja tensión: primero, la media tensión continua es convertida en media tensión alterna a alta frecuencia; esta tensión es reducida a baja tensión preservando la alta frecuencia mediante el transformador, finalmente, la tensión en el terminal de salida del transformador es rectificada y convertida en baja tensión continua). La entrada en la etapa de salida en BT es, por tanto, una tensión continua que es convertida en tensión alterna a frecuencia de operación 50 Hz mediante un convertidor que funciona como inversor. Puesto que el diseño del dispositivo estudiado en esta tesis es bidireccional, en caso de que la potencia tenga que fluir desde el lado de BT al lado de MT, la función de los convertidores se invierte (es decir, los rectificadores pasan a operar como inversores, los inversores pasan a operar como rectificadores) en cualquiera de las etapas. Los actuales semiconductores solo pueden ser utilizados en aplicaciones de media y alta tensión empleando convertidores multi-nivel. Durante los últimos años ha ganado popularidad la tecnología MMC (modular multilevel converter), que permite diseñar configuraciones adecuadas para el lado de MT de un transformador de estado sólido; sus principales ventajas están en modularidad y escalabilidad: el nivel de tensión adecuado se puede conseguir mediante la conexión en serie de tantos sub-módulos como sea necesario. Además con la tecnología MMC se puede obtener una alta calidad en las ondas de tensión y corriente, así como un elevado rendimiento con tamaño reducido en los filtros de entrada. Esta tesis propone un diseño trifásico bidireccional con las siguientes características: - La etapa de entrada está conectada a una red de distribución en MT mediante filtros RL y su configuración trifásica usa convertidores de tecnología MMC. - La etapa intermedia contiene tres secciones: un convertidor monofásico en configuración MMC, un transformador de MT/BT y alta frecuencia, y un convertidor monofásico en BT. - La etapa de salida en BT usa un convertidor trifásico PWM (pulse wide modulation), con un filtro RL para las corrientes y un banco de condensadores para filtrar tensiones. Los convertidores han sido implantados en Matlab/Simulink y simulados considerando modelos con y sin pérdidas en los semiconductores, mientras que el modelo completo de transformador de estado sólido ha sido analizado considerando dos configuraciones distintas del sistema a estudiar: el transformador aislado y formando parte de una red de distribución en MT. Los modelos de transformador con y sin pérdidas han sido simulados bajo ciertas condiciones de operación. Los resultados confirman que la configuración seleccionada para cada etapa del nuevo dispositivo permite obtener un diseño fiable que puede mejorar el funcionamiento de las futuras redes inteligentes.

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Modeling and simulation of a MMC-based solid-state transformer

Cited by 8 publications

References 41 publications

Global Simulation Model Design of Input-Serial, Output-Parallel Solid-State Transformer for Smart Grid Applications

Global Simulation Model Design of Input-Serial, Output-Parallel Solid-State Transformer for Smart Grid Applications

Review of Solid-State Transformer Applications on Electric Vehicle DC Ultra-Fast Charging Station

Advanced modeling of solid state transformer

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