Comparison and Analysis of Improved NLM Strategy for Modular Multilevel Converter in Ship Medium Voltage DC Power System

Chuang Li

《International Core Journal of Engineering》 7卷4期 (2021/04) Pp. 307-316

https://doi.org/10.6919/ICJE.202104_7(4).0042

摘要

Modular multilevel converter (MMC) is applied to medium voltage direct current (MVDC) of ships, In MVDC power system, due to the small number of sub modules, using the traditional nearest level modulation (NLM) strategy, the harmonic content of output voltage is large and the voltage distortion is high. Therefore, it is of great significance to optimize the modulation strategy to improve the harmonic content of output voltage. The working principle and characteristics of traditional NLM modulation strategy, output 2N+1 level NLM modulation strategy and hybrid NL-PWM modulation strategy are compared and analyzed. The simulation model is built on MATLAB/Simulink platform, and the differences of harmonic characteristics of output voltage among the three modulation strategies are analyzed. Finally, the characteristics of the two optimized modulation strategies are summarized.

關鍵字

Modular Multilevel Converter(MMC) ； Medium Voltage DC(MVDC) Power System ； Nearest Level Modulation(NLM) ； Hybrid Nearest Level Pulse Width Modulation ； Output Harmonic Characteristics

參考文獻

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