TY - GEN

T1 - Multilevel converter with variable flying capacitor voltage used for virtual infinite capacitor

AU - Lin, Jun

AU - Weiss, George

N1 - Publisher Copyright:
© 2017 IEEE.

PY - 2017/12/8

Y1 - 2017/12/8

N2 - We evaluate the flying capacitor multilevel converter (FCMC) with one switched-capacitor cell under asymmetric working condition, as a highly efficient hardware realization for the virtual infinite capacitor (VIC). The VIC is a type of electronic circuit, recently introduced to replace large, expensive and unreliable electrolytic capacitors, mainly intended for smoothing random fluctuations of a DC bus voltage V. By the proposed novel control algorithm, the pulsating power that the VIC takes away from the DC bus is shared among the main buffering and the flying capacitors, with the proportion set by a prescribed value. This facilitates to reduce the physical size of the converter, and hence achieve higher power density. This flying capacitor converter operates in an unconventional way, as the flying capacitor voltage is highly variable and hence the converter works under an asymmetric scenario. An average model of this specific working mode is presented, with the design of a linearized current controller. To improve the capacitance reduction ratio, the average value the of flying capacitor voltage is regulated to a relatively high value, instead of V/2. This is achieved by adjusting the phase shift of the PWM carriers. Both continuous and discontinuous conduction modes are investigated, and verified by simulation.

AB - We evaluate the flying capacitor multilevel converter (FCMC) with one switched-capacitor cell under asymmetric working condition, as a highly efficient hardware realization for the virtual infinite capacitor (VIC). The VIC is a type of electronic circuit, recently introduced to replace large, expensive and unreliable electrolytic capacitors, mainly intended for smoothing random fluctuations of a DC bus voltage V. By the proposed novel control algorithm, the pulsating power that the VIC takes away from the DC bus is shared among the main buffering and the flying capacitors, with the proportion set by a prescribed value. This facilitates to reduce the physical size of the converter, and hence achieve higher power density. This flying capacitor converter operates in an unconventional way, as the flying capacitor voltage is highly variable and hence the converter works under an asymmetric scenario. An average model of this specific working mode is presented, with the design of a linearized current controller. To improve the capacitance reduction ratio, the average value the of flying capacitor voltage is regulated to a relatively high value, instead of V/2. This is achieved by adjusting the phase shift of the PWM carriers. Both continuous and discontinuous conduction modes are investigated, and verified by simulation.

KW - Virtual infinite capacitor

KW - asymmetric variable flying capacitor voltage

KW - continuous/discontinuous conduction mode

KW - flying capacitor voltage balancing

KW - multilevel converter

KW - ripple elimination

KW - voltage balance control

UR - http://www.scopus.com/inward/record.url?scp=85046621388&partnerID=8YFLogxK

U2 - 10.1109/PEE.2017.8171698

DO - 10.1109/PEE.2017.8171698

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AN - SCOPUS:85046621388

T3 - 19th International Symposium on Power Electronics, Ee 2017

SP - 1

EP - 6

BT - 19th International Symposium on Power Electronics, Ee 2017

PB - Institute of Electrical and Electronics Engineers Inc.

T2 - 19th International Symposium on Power Electronics, Ee 2017

Y2 - 19 October 2017 through 21 October 2017

ER -