Modulation Scheme for an Effective Increase in the Number of Levels of DC-DC Multi-Level Flying Capacitor Converters
Modulation Scheme for an Effective Increase in the Number of Levels of DC-DC Multi-Level Flying Capacitor Converters
复制标题
有效增加DC-DC多级飞电容转换器级数的调制方案
DOI：
10.1109/apec.2019.8722325
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
A. Prodic
中科院分区：
文献类型：
--
作者：
Michael Halamíček;T. McRae;N. Vukadinović;A. Prodic
This paper introduces a novel modulation scheme for dc-dc multi-level flying capacitor buck converters that effectively increases the number of converter levels. It is shown that, in general, an N-level flying capacitor converter can be split simultaneously into an $\frac{{N + 2}}{2}$ and an $\frac{{N + 3}}{2}$ level flying capacitor converter. This modulation scheme creates unequal differences between the flying capacitor voltages which can be used to reduce the voltage swing at the switching node and thus the size of the inductor. The voltage swing becomes equivalent to an $\frac{{{N^2} + 3}}{4}$ level converter for some conversion ratios. Additionally, this modulation scheme has passive flying capacitor voltage balancing, simplifying controller design. A 5-level flying capacitor converter was modulated to create a 3,4-level converter with the effective voltage swing of a 7-level converter. The functionality of this modulation scheme was confirmed with a 24V-to-9V, 45W 5-level buck converter confirming a 35% reduction in the inductor ripple and, thus, allowing for the equivalent inductor reduction.
This paper introduces a novel modulation scheme for dc-dc multi-level flying capacitor buck converters that effectively increases the number of converter levels. It is shown that, in general, an N-level flying capacitor converter can be split simultaneously into an $\frac{{N + 2}}{2}$ and an $\frac{{N + 3}}{2}$ level flying capacitor converter. This modulation scheme creates unequal differences between the flying capacitor voltages which can be used to reduce the voltage swing at the switching node and thus the size of the inductor. The voltage swing becomes equivalent to an $\frac{{{N^2} + 3}}{4}$ level converter for some conversion ratios. Additionally, this modulation scheme has passive flying capacitor voltage balancing, simplifying controller design. A 5-level flying capacitor converter was modulated to create a 3,4-level converter with the effective voltage swing of a 7-level converter. The functionality of this modulation scheme was confirmed with a 24V-to-9V, 45W 5-level buck converter confirming a 35% reduction in the inductor ripple and, thus, allowing for the equivalent inductor reduction.