Quasi-Square-Wave Modulation of Modular Multilevel High-Frequency DC Converter for Medium-Voltage DC Distribution Application

Wang, Yu; Song, Qiang; Zhao, Biao; Li, Jianguo; Sun, Qianhao; Liu, Wenhua

doi:10.1109/tpel.2017.2772833

Cited by 61 publications

(15 citation statements)

References 32 publications

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“…The difference of average switching frequency is small because the output state rotates among each SM. High dv/dt problem comes from the block-voltage outputs by the proposed modulation can be relieved by using quasi-square-wave modulation (QSWM) [31].…”

Section: E Capacitor Voltage-balancing Analysismentioning

confidence: 99%

Hybrid-Frequency Cascaded Full-Bridge Solid-State Transformer

Zhang

Long

et al. 2019

IEEE Access

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Modular solid-state transformers (SSTs) are suitable for various voltage-and power-level applications. State-of-the-art modular-SST topologies contain a considerable quantity of high-frequency transformers (HFTs) and power switches, thereby increasing the costs, difficulty, and workloads of engineering. To overcome this challenge, a new SST topology family, namely, hybrid-frequency cascaded full-bridge SST (HCFB-SST), is established on the basis of the concept of hybrid-frequency modulation. In comparison with modular-multilevel converter SST (M 2 LC-SST) or CFB-SST, the HCFB-SST uses only 50%-66.7% and 1.11%-10% the device count of power switches and HFTs, respectively, in typical applications, thereby obtaining considerable cost savings. It also achieves a cost reduction of sub-module redundancy. In addition, HCFB-SSTs have simple engineering and compact structures. A hybrid-frequency modulation method is proposed for a low well-balanced average switching frequency and a high equivalent switching frequency without monitoring the bridge-arm current. Analysis and comparison of the semiconductor loss with existing topologies are presented. The simulation studies are conducted to validate the effective function of HCFB-SST and the proposed modulation method. INDEX TERMS Solid-state transformer, hybrid-frequency modulation, cascaded full bridge.

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Section: E Capacitor Voltage-balancing Analysismentioning

confidence: 99%

Hybrid-Frequency Cascaded Full-Bridge Solid-State Transformer

Zhang

Long

et al. 2019

IEEE Access

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show abstract

“…In recent years, DC distribution networks have been increasingly incorporated into electric power systems owing to their stronger controllability, easier compatibility, and lower power losses compared with the corresponding properties of AC distribution networks [1][2][3][4]. Considering that the voltage level of typical DC distribution networks does not exceed 100 kV, the two-level voltage-source converter (VSC) has become a widely used topology for grid-connected converters in DC distribution systems.…”

Section: Introductionmentioning

confidence: 99%

Comprehensive small‐signal model and stability analysis of VSC‐based medium‐voltage DC distribution system

Jiao

2019

IET Generation, Transmission & Distribution

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“…Similar with other IBDCs, the high‐frequency link (HFL) modulation is important for MDCC performance. The square‐wave (SW) modulation and quasi‐square‐wave (QSW) modulation are most widespread HFL modulation methods for IBDCs [9–15]. In existent literatures, SW modulation is most popular since it obtains best power transfer capability and DC voltage utilisation ratio with the same amplitude [9, 10].…”

Section: Introductionmentioning

confidence: 99%