MMC with parallel-connected MOSFETs as an alternative to wide bandgap converters for LVDC distribution networks

The Journal of Engineering

Stephen J. Finney¹  Yanni Zhong¹  Derrick Holliday¹  Nina M. Roscoe¹ 

[1] Department of Electronics and Electrical Engineering, University of Strathclyde, Glasgow, UK

关键词: LVDC networks;    MOSFET;    device stress;    fault tolerance;    MMC;    high-electron-mobility transistor;    power quality;    unity power factor AC-DC converters;    SiC;    reliability;    GaN;    DC–AC converters;    insulated-gate bipolar transistor;    low-voltage direct-current networks;    wide b;    gap converters;    LVDC distribution networks;    conversion loss;    two-level converter;    converter cost;    power loss;    metal–oxide–semiconductor field-effect transistor;    modular multi-level converter;    electromagnetic interference;    conductor utilisation;    heatsink size;    AC–DC/DC–AC converter design;   

DOI  :  10.1049/joe.2017.0073

学科分类：工程和技术（综合）

来源: IET

【 摘 要 】

Low-voltage direct-current (LVDC) networks offer improved conductor utilisation on existing infrastructure and reduced conversion stages, which can lead to a simpler and more efficient distribution network. However, LVDC networks must continue to support AC loads, requiring efficient, low-distortion DC–AC converters. Additionally, increasing numbers of DC loads on the LVAC network require controlled, low-distortion, unity power factor AC-DC converters with large capacity, and bi-directional capability. An AC–DC/DC–AC converter design is therefore proposed in this study to minimise conversion loss and maximise power quality. Comparative analysis is performed for a conventional IGBT two-level converter, a SiC MOSFET two-level converter, a Si MOSFET modular multi-level converter (MMC) and a GaN HEMT MMC, in terms of power loss, reliability, fault tolerance, converter cost and heatsink size. The analysis indicates that the five-level MMC with parallel-connected Si MOSFETs is an efficient, cost-effective converter for low-voltage converter applications. MMC converters suffer negligible switching loss, which enables reduced device switching without loss penalty from increased harmonics and filtering. Optimal extent of parallel-connection for MOSFETs in an MMC is investigated. Experimental results are presented to show the reduction in device stress and electromagnetic interference generating transients through the use of reduced switching and device parallel-connection.

【 授权许可】

CC BY