TY - JOUR
T1 - Improved natural balancing with modified phase-shifted PWM for single-leg five-level flying-capacitor converters
AU - Thielemans, Steven
AU - Ruderman, Alex
AU - Reznikov, Boris
AU - Melkebeek, Jan
N1 - Funding Information:
Manuscript received May 19, 2011; revised July 19, 2011; accepted September 10, 2011. Date of current version February 20, 2012. This work was supported by Research Foundation–Flanders (FWO) under Project G.0011.08 and Project G.0665.06 and by the Interuniversity Attraction Pole under Project (IUAP) P6/21. Recommended for publication by Associate Editor R. Burgos.
Copyright:
Copyright 2012 Elsevier B.V., All rights reserved.
PY - 2012
Y1 - 2012
N2 - Flying-capacitor converters (FCCs), like most multilevel converter topologies, require a balancing mechanism of the capacitor voltages. FCCs feature natural voltage balancing when a special modulation technique is used. The classic methods, such as phase-shifted pulse width modulation (PS-PWM), result in very slow balancing for some duty-ratio ranges. Previous work has shown that for a single-leg five-level FCC, one time constant is infinite for a zero desired output voltage. In this paper, a modified PS-PWM scheme for a single-leg five-level FCC is presented, which results in faster balancing over the total duty-ratio range. The modified PS-PWM scheme is studied, resulting in an averaged voltage-balancing model. This model is verified using simulations and experiments. The modified PS-PWM scheme solves the slow-balancing problems of the normal PS-PWM method for odd-level FCCs, while maintaining the passive control property, and it provides a self-precharge capability.
AB - Flying-capacitor converters (FCCs), like most multilevel converter topologies, require a balancing mechanism of the capacitor voltages. FCCs feature natural voltage balancing when a special modulation technique is used. The classic methods, such as phase-shifted pulse width modulation (PS-PWM), result in very slow balancing for some duty-ratio ranges. Previous work has shown that for a single-leg five-level FCC, one time constant is infinite for a zero desired output voltage. In this paper, a modified PS-PWM scheme for a single-leg five-level FCC is presented, which results in faster balancing over the total duty-ratio range. The modified PS-PWM scheme is studied, resulting in an averaged voltage-balancing model. This model is verified using simulations and experiments. The modified PS-PWM scheme solves the slow-balancing problems of the normal PS-PWM method for odd-level FCCs, while maintaining the passive control property, and it provides a self-precharge capability.
KW - Capacitor voltage balancing
KW - multilevel converters
KW - power converters
KW - pulse width modulation (PWM)
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U2 - 10.1109/TPEL.2011.2169993
DO - 10.1109/TPEL.2011.2169993
M3 - Article
AN - SCOPUS:84857395779
VL - 27
SP - 1658
EP - 1667
JO - IEEE Transactions on Power Electronics
JF - IEEE Transactions on Power Electronics
SN - 0885-8993
IS - 4
M1 - 6030953
ER -