标题：Improved Design and Control of FBSM MMC With Boosted AC Voltage and Reduced DC Capacitance

作者：Hu,Jiabing; Xiang,Muchao; Lin, Lei; Lu,Zengmao; Zhu,Jianhang; He, Zhiyuan

摘要：Reducingthecapacitanceofsubmodules(SM) and handling short-circuit faults in HVdc systems are crucial for economical and reliable operation of modular multilevel converters (MMC). This paper proposes an SM capacitance reduction method for full-bridge submodule (FBSM)-MMC, which combines circulating current injection and ac voltage boosting. An optimized circulating current control method considering the limitation of fixed semiconductor current rating is introduced. By adding secondharmonicvoltagetothereferencearmvoltage,thecapacitor voltageripplecanbecontrolledtobeatargetedvalueunder all operating conditions. To further decrease the SM capacitor voltage ripples, the negative voltage state of FBSM is fully utilized to boost the ac voltage under fixed dc voltage withthemodulationindexupto1.414.Consequently,thecapacitance requirement for ac voltage boosting FBSM-MMC can be significantly reduced as compared to the conventional FBSM-MMC. Experimental results confirm the feasibilityandvalidityoftheproposedSMcapacitancereduction method.

发表于：IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS

发表时间：MAR, 2018