A Novel Z-Type Modular Multilevel Converter With Capacitor Voltage Self-Balancing for Grid-Tied Applications

Zheng, Tong; Gao, Congzhe; Liu, Xiangdong; Liao, Xiaozhong; Liang, Jun; Chen, Zhen; Sun, Baiyan; Lv, Jingliang

doi:10.1109/tpel.2020.2997991

Cited by 17 publications

(5 citation statements)

References 38 publications

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“…The proposed methodology in [29]- [30] produces balanced arm current for MMCs during power mismatch and various grid faults to enhance system reliability. A novel Z-type MMC with self-balanced capacitors is reported in [33]. Power loss associated with the balancing circuit is reduced in this work.…”

Section: Introductionmentioning

confidence: 95%

Single-Sourced Double-Stage Multilevel Inverter for Grid-Connected Solar PV Systems

Tak

Chattopadhyay

Chakraborty

2022

IEEE Open J. Ind. Electron. Soc.

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Design challenges for grid-connected solar PV systems related to the power conditioning units are power quality, efficiency, reliability, cost of implementation etc. This paper deals with single dc sourcebased double LDN high-resolution multilevel inverter topology with the appropriate blend of switches to address most of the practical constraints of central inverter application. A two-stage high-resolution multilevel inverter solution is adapted to double the inverter utilization as well as to increase efficiency. Reactive power handling and fault blocking capability of the system are also demonstrated in this work. The converter is extensively simulated using MATLAB/Simulink. Experimental results from laboratory prototype confirm the usefulness of the proposed concepts.INDEX TERMS Central inverter, Photovoltaic (PV), Grid-connected PV inverter, High frequency switching, Level doubling network (LDN), Multilevel inverter, Maximum power point tracking (MPPT).

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Section: Introductionmentioning

confidence: 95%

Single-Sourced Double-Stage Multilevel Inverter for Grid-Connected Solar PV Systems

Tak

Chattopadhyay

Chakraborty

2022

IEEE Open J. Ind. Electron. Soc.

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“…The third category adds auxiliary hardware circuits such as clamping diodes to the system or uses novel MMC topologies [33][34][35][36][37][38][39][40][41][42][43][44][45][46][47], which will avoid the sampling of bridge arm currents or submodule capacitor voltages, whereas additional clamping components or energy transfer paths are required. There are also other topologies designed for lower energy storage and DC-fault tolerance that require closedloop control [48][49][50][51]. The auxiliary hardware circuits result in the complexity of the topology, increasing the cost of the circuit while decreasing the reliability of the system.…”

Section: Introductionmentioning

confidence: 99%

A capacitor voltage self‐balancing method of modular multilevel converters based on switching state matrix construction

Zhou

Qin

Wang

et al. 2023

IET Power Electronics

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This study presents a submodule capacitor voltage self‐balancing method for modular multilevel converters (MMCs) based on switching state matrix construction, which has an advantage over eliminating massive sensor demanding and alleviating computational burden for a large number of submodules. It is mathematically proved that MMC has only one static equilibrium operating point to which the submodule capacitor voltages will converge naturally by the evaluation of capacitor voltage deviation index. A novel switching state matrix of submodules is constructed off‐line according to the mathematical proof, and the switching state vectors are cyclically selected from the matrix and distributed to the switching gate signals among the submodules to realize capacitor voltage self‐balance, avoiding real‐time capacitor voltage sampling and sorting. The proposed method is compatible with the conventional double closed‐loop control of MMCs. Theoretical conclusions are verified by simulations and experiments.

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“…Its voltage self-balancing control effect is quite satisfying with a much lower real-time computing demand. However, the additional clamp diodes and isolation transformers result in higher topology complexity and circuit cost [5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

A selection principle of submodule switching state vectors for switching frequency reduction in voltage self‐balancing half‐bridge modular multilevel converters

Zhou,

Qin,

Yang

et al. 2023

IET Power Electronics

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The problem of submodule switching frequency reduction in half‐bridge modular multilevel converters (HB‐MMCs) with capacitor voltage self‐balancing control is considered and explored in this paper. A selection principle of submodule switching state vectors is proposed based on the voltage self‐balancing switching state matrix, aiming to lower submodule switching frequency and device losses. The relationship between system stability and submodule switching signals is revealed according to the capacitor voltage self‐balancing characteristics, and the full‐rank constraints on the voltage self‐balancing switching state matrix are proposed. Considering the tradeoff between switching loss and capacitor voltage fluctuation, the evaluation indexes of voltage self‐balancing control effect are determined. The selection principle of submodule switching state vectors and the optimized construction method of switching state matrix are presented. Voltage self‐balancing HB‐MMC models are built in MATLAB/Simulink, and it is verified that the submodule switching state vector selection principle proposed in this study can effectively reduce switching frequency while meeting the evaluation requirements of practical engineering projects, so as to achieve the balance between switching loss and steady‐state capacitor voltage fluctuation.

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A Novel Z-Type Modular Multilevel Converter With Capacitor Voltage Self-Balancing for Grid-Tied Applications

Cited by 17 publications

References 38 publications

Single-Sourced Double-Stage Multilevel Inverter for Grid-Connected Solar PV Systems

Single-Sourced Double-Stage Multilevel Inverter for Grid-Connected Solar PV Systems

A capacitor voltage self‐balancing method of modular multilevel converters based on switching state matrix construction

A selection principle of submodule switching state vectors for switching frequency reduction in voltage self‐balancing half‐bridge modular multilevel converters

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