Open-Loop Control of Modular Multilevel Converters Using Estimation of Stored Energy

Ängquist, Lennart; Antonopoulos, Antonios; Siemaszko, Daniel; Ilves, Kalle; Vasiladiotis, Michail; Nee, H-P

doi:10.1109/tia.2011.2168593

Cited by 317 publications

(134 citation statements)

References 13 publications

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“…The open-loop control was proposed in [12] as an improvement over the direct modulation. The motivation was double: (i) to avoid the measurement delays associated with the retrieval of the summed branch capacitor voltages and (ii) to lower the number of exchanged signals between the cells and the central controller.…”

Section: ) Open-loop Controlmentioning

confidence: 99%

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Modular Multilevel Converter Control Methods Performance Benchmark for Medium Voltage Applications

Christe

Dujić

2019

IEEE Trans. Power Electron.

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Abstract-Modular multilevel converters are increasingly being considered or used for various medium voltage applications. Multiple control methods have been proposed for the control of the direct to three-phase modular multilevel converter. They differ one from another in the way the capacitor voltage ripples are handled, i.e. either neglected, estimated, reconstructed by filtering or measured. This has implications on the performance level that can be obtained. This paper provides insights on the advantages and drawbacks of each control method, in inverter and rectifier mode, with a fair and thorough assessment supported by extensive simulations, with converter ratings that are realistic for medium voltage applications. Finally, this works highlights the impact of the higher dynamics for medium voltage dc applications compared to high voltage dc ones on the choice of the control method.

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Section: ) Open-loop Controlmentioning

confidence: 99%

“…Numerous control methods have been proposed in the literature [12]- [14] and tailored for specific applications or with a specific shaping of the outer loops to achieve a desired converter behaviour. The differences stem from the way the capacitor voltage ripples are handled, i.e.…”

mentioning

confidence: 99%

Modular Multilevel Converter Control Methods Performance Benchmark for Medium Voltage Applications

Christe

Dujić

2019

IEEE Trans. Power Electron.

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“…However, the implementation process is complex and switching frequency is high. As for the NLM methods [12]- [18], the characteristics of a low switching frequency and a simple implementation can be obtained. However, they are mainly applied on the occasion of a large number of SMs to achieve a good quality of the output voltage.…”

Section: Introductionmentioning

confidence: 99%

A Hybrid Modular Multilevel Converter Topology with an Improved Nearest Level Modulation Method

Wang¹,

Han²,

Bai³

2017

Journal of Power Electronics

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In this paper, a hybrid modular multilevel converter (MMC) topology with an improved nearest level modulation method is proposed for medium-voltage high-power applications. The arm of the proposed topology contains N series connected half-bridge submodules (HBSMs), one full-bridge submodule (FBSM) and an inductor. By exploiting the FBSM, half-level voltages are obtained in the arm voltages. Therefore, an output voltage with a 2N+1 level number can be generated. Moreover, the total level number of the inserted submodules (SMs) is a constant. Thus, there is no pulse voltage across the arm inductors, and the SM capacitor voltage is rated. With the proposed voltage balancing method, the capacitor voltage of the HBSM is twice the voltage of the FBSM, and each IGBT of the FBSM has a relatively low switching frequency and an equalized conduction loss. The capacitor voltage balancing methods of the two kinds of SMs are implemented independently. As a result, the switching frequency of the HBSM is not increased compared to the conventional MMC. In addition, according to a theoretical calculation of the total harmonic distortion of the electromotive force (EMF), the voltage quality with the presented method can be significantly enhanced when the SM number is relatively small. Simulation and experimental results obtained with a MMC-based inverter verify the validity of the developed method.

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“…No entanto, os sensores de tensão necessitam ter uma banda passante maior para medir as tensões de saída, quando forem utilizadas estratégias de modulação por largura de pulso (PWM) e devem ter maior capacidade de isolamento de tensão. Estratégias de controle em malha aberta com técnicas de rotação de pulsos [19]- [21], com observadores da energia armazenada [22] ou com padrão de pulso específico [23] têm sido propostas para o controle do MMC com requisitos mínimos de comunicação. Salienta-se que estas técnicas não utilizam as informações das tensões dos capacitores, o que pode comprometer a estabilidade do MMC.…”

Section: Introductionunclassified

Observador Por Modos Deslizantes Aplicado No Controle Das Tensões Equivalentes Dos Polos Em Conversores Multiníveis Modulares

Silva¹,

Vieira²,

Rech³

2017

Eletrônica de Potência

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Resumo -Este artigo propõe um observador por modos deslizantes aplicado no controle das tensões equivalentes dos polos de conversores multiníveis modulares (MMC) em aplicações com elevado número de submódulos conectados em série, com o objetivo de reduzir a complexidade do sistema de comunicação. Esta técnica é utilizada no sistema de controle do MMC, possibilitando uma implementação mais simples, uma vez que não é necessário o envio das tensões de todos os capacitores para o processador central. O observador proposto possui um termo adicional que permite um melhor desempenho transitório, ao contrário de observadores por modos deslizantes já propostos. Adicionalmente, uma análise de estabilidade por Lyapunov é apresentada juntamente com a definição dos ganhos do observador. Resultados de simulação e experimentais são incluídos para demonstrar o adequado desempenho do observador com o sistema de controle do MMC sob diferentes condições de operação. Palavras-chave - SLIDING MODE OBSERVER APPLIED ON EQUIVALENT ARM VOLTAGE CONTROL IN MODULAR MULTILEVEL CONVERTERSAbstract -This paper proposes a sliding mode observer (SMO) for equivalent capacitor voltages control in modular multilevel converters (MMC) to reduce the communication complexity in applications with high number of series-connected submodules. This technique is used in the MMC control system and allows a simpler MMC implementation, since the individual capacitor voltages are not used in the central processor. The observer has an additional term that allows a better transient performance, unlike to the already proposed SMOs. In addition, the Lyapunov stability analysis of the SMO is presented with the design of the observer gains. Simulation and experimental results are included to demonstrate the suitable SMO performance with the MMC control system under different operating conditions.

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Open-Loop Control of Modular Multilevel Converters Using Estimation of Stored Energy

Cited by 317 publications

References 13 publications

Modular Multilevel Converter Control Methods Performance Benchmark for Medium Voltage Applications

Modular Multilevel Converter Control Methods Performance Benchmark for Medium Voltage Applications

A Hybrid Modular Multilevel Converter Topology with an Improved Nearest Level Modulation Method

Observador Por Modos Deslizantes Aplicado No Controle Das Tensões Equivalentes Dos Polos Em Conversores Multiníveis Modulares

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