A 48V:2V flying capacitor multilevel converter using current-limit control for flying capacitor balance
A 48V:2V flying capacitor multilevel converter using current-limit control for flying capacitor balance
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一种采用限流控制实现飞跨电容平衡的 48V:2V 飞跨电容多电平转换器
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
J. Stauth
中科院分区：
文献类型：
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作者：
Jan S. Rentmeister;J. Stauth
这项工作探讨了众所周知的挑战，实现任意（N级）飞跨电容多电平（FCML）转换器的电容器的电压平衡。特别是，我们探讨了可测量的电路波形和飞跨电容器电压“状态”之间的关系。这些用于导出确保中值电容器电压电平平衡的一组充分条件。它示出，各种形式的电流限制控制（例如，传统的峰值或谷值电流模式控制，或低频采样调节的峰谷电流电平），结合适度的附加标准，将保证电压平衡。这一概念在一款采用48 V电源、2 V输出和最高10 A负载电流的7电平FCML转换器中得到了突出体现。该转换器采用GaN动力系统，实现紧凑布局和低寄生效应。数字控制算法用于调节谷值电流和转换器输出电压。在实验样机中突出了谷值电流检测和嵌套式低频反馈调节。
This work explores the well-known challenge of achieving voltage balance of capacitors in arbitrary (N-level) flying capacitor multilevel (FCML) converters. In particular, we explore the relationships among measurable circuit waveforms and flying capacitor voltage ‘states’. These are used to derive a set of sufficient conditions that ensure balance of the median capacitor voltage levels. It is shown that various forms of current-limit control (e.g. traditional peak or valley current-mode control, or low-frequency sampled regulation of peak of valley current levels), combined with modest additional criteria, will guarantee voltage balance. The concept is highlighted with a 7-level FCML converter operating with a 48 V supply, a 2 V output, and up to 10 A load current. The converter uses a GaN powertrain to achieve a compact layout and low parasitics. A digital control algorithm is used to regulate valley currents and the converter output voltage. Valley current detection and nested low-frequency feedback regulation is highlighted in the experimental prototype.