TY - GEN
T1 - Component sizing and voltage balancing of MMC-based solid-state transformers under various AC-link excitation voltage waveforms
AU - Zhang, Lei
AU - Qin, Jiangchao
AU - Duan, Qing
AU - Sheng, Wanxing
PY - 2019/5/24
Y1 - 2019/5/24
N2 - Modular multilevel converter (MMC) has been employed for solid state transformer (SST) applications. For the MMC-based SSTs, ac-link excitation voltage waveforms are multilevel and controllable for energizing medium-frequency transformers. Different multilevel ac-link voltage waveforms have different performance and specification requirements in design and control. In this paper, power transfer characteristics and capacitor voltage ripple are investigated for the MMC-SSTs under different ac-link excitation voltage waveforms, i.e., sinusoidal and generalized non-sinusoidal voltages. Based on the analysis, capacitance and inductance sizing method is developed and verified. To address voltage balancing issue of the MMC under medium-frequency operating conditions, various capacitor voltage balancing methods are evaluated and compared based on phase-shift modulation and nearest-level modulation methods. The study is conducted in the PSCAD/EMTDC software environment. The study results show that, for the same design specifications, different ac-link excitation voltage waveforms have different capacitance requirements, which can be used for optimization design of the MMC-SSTs.
AB - Modular multilevel converter (MMC) has been employed for solid state transformer (SST) applications. For the MMC-based SSTs, ac-link excitation voltage waveforms are multilevel and controllable for energizing medium-frequency transformers. Different multilevel ac-link voltage waveforms have different performance and specification requirements in design and control. In this paper, power transfer characteristics and capacitor voltage ripple are investigated for the MMC-SSTs under different ac-link excitation voltage waveforms, i.e., sinusoidal and generalized non-sinusoidal voltages. Based on the analysis, capacitance and inductance sizing method is developed and verified. To address voltage balancing issue of the MMC under medium-frequency operating conditions, various capacitor voltage balancing methods are evaluated and compared based on phase-shift modulation and nearest-level modulation methods. The study is conducted in the PSCAD/EMTDC software environment. The study results show that, for the same design specifications, different ac-link excitation voltage waveforms have different capacitance requirements, which can be used for optimization design of the MMC-SSTs.
KW - Capacitor voltage ripple
KW - Modular multilevel converter (MMC)
KW - Solid state transformer (SST)
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U2 - 10.1109/APEC.2019.8721891
DO - 10.1109/APEC.2019.8721891
M3 - Conference contribution
AN - SCOPUS:85067099432
T3 - Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC
SP - 371
EP - 375
BT - 34th Annual IEEE Applied Power Electronics Conference and Exposition, APEC 2019
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 34th Annual IEEE Applied Power Electronics Conference and Exposition, APEC 2019
Y2 - 17 March 2019 through 21 March 2019
ER -