Multilevel inverters provide appealing advantages such as improved efficiency, superior thermal performance, better distribution of the switching and conduction power losses, smaller size of passive components including output ac filters and EMI filters, as compared to their two-level counterparts. The flying-capacitor (FC)-based topologies are attaining more attentions, and are finding lots of medium-voltage and low-voltage industrial and residential applications. The FC-based active neutral-point-clamped (ANPC) inverter, as a hybrid topology based on the three-level ANPC and the FC-based configurations, offers outstanding advantages including the reduced number of FCs as well as switching power cells, improved efficiency, and enhanced power quality. However, the utilization of high-voltage line-frequency switches, as a major drawback, hinders the ANPC converter from expansion and penetration into the high-voltage ranges. The dual flying-capacitor (DFC)-ANPC topology resolves this issue through introducing the zero-voltage-switching (ZVS) feature into the line-frequency devices. This soft-switching makes it possible to use the series connection of several low-voltage devices for the realization of the high-voltage switches without having the transient voltage imbalance issues. This article studies the thermal benefits that are achieved in the DFC-ANPC topology alongside the ZVS operation of its line-frequency high-voltage switches. Furthermore, an active voltage balancing technique, based on logic-equations, is proposed in this article for control of the FCs’ voltages. The experimental results are provided to validate the improved thermal performance of the DFC-ANPC topology as well as the active balancing technique for the regulation of the FC voltages.

中文翻译：

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双飞电容有源中性点钳位（DFC-ANPC）逆变器的有源电压平衡和热性能分析

与两电平逆变器相比，多电平逆变器具有吸引人的优势，例如提高效率、卓越的热性能、更好的开关和传导功率损耗分布、包括输出交流滤波器和 EMI 滤波器在内的无源元件尺寸更小。基于飞电容 (FC) 的拓扑结构越来越受到关注，并在中压和低压工业和住宅应用中得到广泛应用。基于 FC 的有源中性点钳位 (ANPC) 逆变器作为基于三电平 ANPC 和基于 FC 配置的混合拓扑结构，具有突出的优势，包括减少 FC 数量以及开关电池、改进效率，提高电能质量。然而，使用高压线频开关是一个主要缺点，阻碍 ANPC 转换器扩展和渗透到高压范围。双飞跨电容器 (DFC)-ANPC 拓扑通过将零电压开关 (ZVS) 功能引入线频设备来解决此问题。这种软开关使得可以使用多个低压器件的串联来实现高压开关，而不会出现瞬态电压不平衡问题。本文研究了在 DFC-ANPC 拓扑中与其工频高压开关的 ZVS 操作一起实现的热优势。此外，本文提出了一种基于逻辑方程的有源电压平衡技术，用于控制 FC 的电压。