Impedance Modeling and Analysis of Series-Connected Modular Multilevel Converter (MMC) and its Comparative Study With Conventional MMC for HVDC Applications

Wang, Can; Xu, Jiexiong; Pan, Xuewei; Gong, Wenming; Xu, Shukai; Zhu, Zhe

doi:10.1109/tpwrd.2021.3125699

Cited by 39 publications

(11 citation statements)

References 20 publications

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“…The traditional voltage equalization algorithm, no matter what optimization method is used in the sequencing process, ultimately requires the equalization of sub-modules by changing the order of the driving signal [7] , which makes different sub-modules have different conduction times in a sinusoidal cycle, and the switching loss is an important factor in determining the heat generation of IGBTs. The uneven switching times of sub-modules brought by the traditional voltage equalization algorithm increase the upper limit of IGBT heat generation [8][9][10] , which in turn limits the thermal selection of the main circuit and increases the manufacturing cost [11] .…”

Section: Pressure Equalization Control Algorithm and Dsp Automatic Co...mentioning

confidence: 99%

Implementation of Automatic DSP Code Generation Based on Closed-loop Algorithm for Three-level Inverters

Zhang,

Zhang

2023

J. Phys.: Conf. Ser.

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Wind energy has the advantages of wide distribution, renewable, and non-polluting, so it is receiving more and more attention from more and more countries. As more and more wind power systems are integrated into the grid, it has an impact on the stability of the grid. To keep the power system stable, there is an urgent need for a grid simulator that can simulate various behaviors of the grid and test the reliability of the wind turbine before grid integration. Inverters, especially multilevel inverters, as the core part of the grid simulator, have been widely studied by scholars in recent years. However, compared to conventional inverters, multilevel inverters are characterized by high code development effort, great difficulty, and a long development period. In this paper, we adopt an automatic DSP code generation method with MATLAB hardware support package and give a complete system design method and development flow based on MATLAB and TMSF28335 automatic code generation. Finally, we take the closed-loop three-level MMC inverter as an example, propose an equalization algorithm suitable for automatic code generation for the capacitor-voltage balancing part, and verify the feasibility of the DSP automatic code generation in a multilevel inverter development. The feasibility of DSP automatic code generation in the development of a multilevel inverter is verified. The experimental results show that the proposed equalization algorithm with variable reference coefficient and DSP automatic code generation method can be used in the development of a multilevel inverter, which can improve development efficiency and reduce development costs.

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Section: Pressure Equalization Control Algorithm and Dsp Automatic Co...mentioning

confidence: 99%

Implementation of Automatic DSP Code Generation Based on Closed-loop Algorithm for Three-level Inverters

Zhang,

Zhang

2023

J. Phys.: Conf. Ser.

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“…Modular multilevel converters (MMCs) represent a popular topology of voltage source converters in high-voltage direct current (HVDC) transmission systems [1][2][3][4][5][6]. MMC-HVDC systems typically involve a large number of submodules (SMs).…”

Section: Introductionmentioning

confidence: 99%

Semi‐hot redundant control method for modular multilevel converter‐based high‐voltage direct current systems under submodules fault

Yang

Jia

Zou

et al. 2023

IET Power Electronics

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A modular multilevel converter‐based high voltage direct current (MMC‐HVDC) system involves a large number of cascading submodules (SMs). The failure of SMs may critically degrade the system performance. Therefore, several redundant SMs can be incorporated and reasonably controlled to ensure the system reliable and continuous operation even if certain SMs fail. This paper proposes a semi‐hot redundant method for MMC‐HVDC systems. In the proposed strategy, when the system operates normally, the redundant SMs are controlled in a lower voltage range. These SMs do not require frequent charging and discharging, which decreases the switching loss. When ordinary SMs fail, the faulty SMs are bypassed and the corresponding number of redundant SMs can be promptly recharged to the rated voltage to replace the faulty SMs. The semi‐hot reserved SMs can shorten the transient process of faulty SMs replacement, and in this process, the absence of faulty SMs does not considerably influence the system. Thus, the original control and modulation strategies of the system do not need to be modified when several SMs fail. The performance of the proposed method is compared with those of the existing methods, and its validity is demonstrated through a small‐scale experimental prototype.

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“…Obviously, as the number of bridge arm SMs grows, the computational complexity of FCS-MPC grows dramatically. [17] proposed an indirect FCS-MPC that limits the evaluation scope to (n+1) 2 and uses a sorting technique to achieve SM capacitor voltage balance. In [18]- [19], a simplified rolling optimization algorithm is proposed, with an optimization scope of (n+1).…”

Section: Introductionmentioning

confidence: 99%

Compensatory Model Predictive Current Control for Modular Multilevel Converter With Reduced Computational Complexity

et al. 2022

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Model predictive control (MPC) is widely used in modular multilevel converter (MMC) control because of its strong robustness, fast dynamic response, and strong stability. Traditional MPC must traverse several switch combinations to accurately regulate the output current and circulating current of the MMC. Therefore, as the number of sub-module (SM) grows, the controller's computational complexity grows. This paper proposes a compensatory model predictive current control (CMPCC) for inner loop current control. It immediately estimates the number of SMs required by the bridge arm without scrolling optimization, reducing the amount of calculation of the system and improving the output current and circulating current tracking accuracy to the references. The objective function is established based on the system output current and internal circulation current by developing the discretization mathematical model of MMC. On the basis of minimizing the optimization scope, the compensation prediction is achieved through the volt-second balance, to achieve effective current control. Subsequently, an uneven bucket sorting algorithm is proposed to drastically eliminate the unnecessary sorting process. Finally, both a MATLAB/Simulink model and an experimental platform of MMC are built. To verify the practicality of the proposed control strategy, simulation and hardware experiments are provided.

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Impedance Modeling and Analysis of Series-Connected Modular Multilevel Converter (MMC) and its Comparative Study With Conventional MMC for HVDC Applications

Cited by 39 publications

References 20 publications

Implementation of Automatic DSP Code Generation Based on Closed-loop Algorithm for Three-level Inverters

Implementation of Automatic DSP Code Generation Based on Closed-loop Algorithm for Three-level Inverters

Semi‐hot redundant control method for modular multilevel converter‐based high‐voltage direct current systems under submodules fault

Compensatory Model Predictive Current Control for Modular Multilevel Converter With Reduced Computational Complexity

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