本論文將介紹四階層飛馳電容圖騰柱功率因數修正器。傳統二階層架構操作於連續導通模式下，硬切損失的關係使得切換頻率受限於低頻切換，因此難以將磁性元件小型化。多階層飛馳電容架構與二階層架構相比能使用較低感值的電感和體積小的陶瓷電容來達到高功率密度。多階層飛馳電容架構採用相移式脈波寬度調變來控制飛馳電容的電壓平衡、增加開關切換點的等效切換頻率並減少電感上的跨壓來降低電感電流漣波。四階層飛馳電容型圖騰柱功率因數修正器因慢速臂開關的輸出電容非線性的特性，在輸入電壓零交越後產生電感電流突波問題，透過數學分析提出合適的控制策略。本論文將比較多階層飛馳式電容架構與多相交錯式架構的差異、說明四階層飛馳電容圖騰柱功率因數修正器的動作原理、同步整流開關與輸入電壓零交越的控制方法及電感電流採樣的考量。本論文最終實現高效率高功率密度之四階層飛馳電容圖騰柱功率因數修正器，其輸入電壓從90 Vrms到230 Vrms、輸出電壓380 V、輸出功率為2.6 kW、峰值效率達99.11 %。

This dissertation will introduce the four-level flying capacitor totem-pole PFC converter. Traditional two-level topology operates at continuous conduction mode with low switching frequency which is limited by the hard-switching loss and it is hard to minimize the magnetic component. Compared to two-level topology, flying capacitor multilevel (FCML) topology can achieve high power density due to the lower inductance and the small volume size of ceramic capacitor. Phase-shift pulse-width modulation is commonly used in flying capacitor multilevel topologies to achieve the voltage balancing of flying capacitor, increase the equivalent frequency of switching node voltage and reduce the voltage across the inductor. Therefore, the inductor current ripple can be further reduced. Due to the non-linear output capacitance Coss characteristic of MOSFET, the inductor current spike will occur at input voltage zero-crossing region. By derived the equation of current spike in mathematical theory to propose the suitable control strategy for four-level flying capacitor bridgeless totem-pole PFC converter. The detailed comparison of the current ripple between flying capacitor multilevel topology and multi-phase interleaved topology, the circuit operating principle, the control method of synchronous rectifier, the control strategy at input voltage zero-crossing and the considerations of the inductor current sensing are discussed. The four-level flying capacitor bridgeless totem-pole PFC converter with high power density and high efficiency is implemented and the input voltage range is from 90 Vrms to 230 Vrms. The maximum output power is tested up to 2.6 kW and the peak efficiency with 99.11% is achieved.

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