TY - JOUR
T1 - Switching Frequency Analysis of Staircase-Modulated Modular Multilevel Converters and Equivalent PWM Techniques
AU - Konstantinou, G.
AU - Pou, J.
AU - Ceballos, Salvador
AU - Darus, R.
AU - Agelidis, V.G.
N1 - Publisher Copyright:
© 1986-2012 IEEE.
PY - 2016/2
Y1 - 2016/2
N2 - The large number of voltage levels in a modular multilevel converter (MMC) make staircase modulation a feasible alternative, particularly in high-power applications. However, staircase waveforms do not necessarily mean operation of the MMC submodules (SMs) at the fundamental frequency. This paper presents an analysis of SM switching frequencies in staircase-modulated MMCs and their correlation to the modulation index and load phase angle. A carrier-based pulsewidth-modulation (CB-PWM) equivalent technique is also developed. This analysis demonstrates that CB-PWM techniques provide a similar switching frequency with superior harmonic performance and improved voltage balancing characteristics at all modulation indices compared to staircase modulation. The theoretical analysis is verified with extensive simulation results for MMCs with different SMs and experimental results from a laboratory prototype.
AB - The large number of voltage levels in a modular multilevel converter (MMC) make staircase modulation a feasible alternative, particularly in high-power applications. However, staircase waveforms do not necessarily mean operation of the MMC submodules (SMs) at the fundamental frequency. This paper presents an analysis of SM switching frequencies in staircase-modulated MMCs and their correlation to the modulation index and load phase angle. A carrier-based pulsewidth-modulation (CB-PWM) equivalent technique is also developed. This analysis demonstrates that CB-PWM techniques provide a similar switching frequency with superior harmonic performance and improved voltage balancing characteristics at all modulation indices compared to staircase modulation. The theoretical analysis is verified with extensive simulation results for MMCs with different SMs and experimental results from a laboratory prototype.
KW - Modular multilevel converter (MMC)
KW - Multilevel converters
KW - Pulsewidth modulation (PWM)
KW - Modular multilevel converter (MMC)
KW - Multilevel converters
KW - Pulsewidth modulation (PWM)
UR - http://www.scopus.com/inward/record.url?scp=84962424940&partnerID=8YFLogxK
U2 - 10.1109/TPWRD.2015.2416759
DO - 10.1109/TPWRD.2015.2416759
M3 - Article
VL - unknown
SP - 28
EP - 36
JO - unknown
JF - unknown
IS - 1
M1 - 7070753
ER -