使用開路電壓法最大功率點追蹤功能之寬輸入功率範圍自激振盪切換電容式電壓轉換器

A Wide Input Power Range Self-Oscillating Switched-Capacitor Converter with FOCV-Based MPPT

吳敏萱(Min-Hsuan Wu)

指導教授 ： 劉深淵

國立臺灣大學/電機資訊學院/電子工程學研究所/碩士(2021年)

https://doi.org/10.6342/NTU202100373

摘要

這篇論文主要分為兩個部分，第一部分實現了一個寬輸入功率範圍之自激振盪式直流電壓轉換器。在切換電容式直流電壓轉換器(SCC)的架構下引進自激振盪的機制可以省略掉產生控制開關週期信號的振盪器，進而減少功率損耗。所提出之轉換器為多層架構，其操作原理近似於迪克森電荷泵(DCP)，故能在寬輸入功率範圍下減少寄生電容所造成之損耗。此轉換器量測之輸入功率範圍為33.9nW到851μW，最高之功率轉換效率(PCE)為47.9%。
第二部分延伸前述之電壓轉換器，實現了一個室內光源之能量擷取系統。此系統加入了最大功率點追蹤功能(MPPT)，使光伏電池所能提供之輸入功率最大化。此最大功率點追蹤功能主要是使用開路電壓法(FOCV)，但無需傳統FOCV所需之輸入功率開關。此方法可避免在取樣開路電壓時斷開轉換器，也能排除在設計輸入功率開關時所面臨之開關導通損耗與驅動損耗間之權衡。此系統實現於0.18微米CMOS製程，有效面積0.86平方毫米。其自光伏電池至輸出之總功率轉換效率約為30%，最高值發生在光伏電池所能提供之最大輸入功率為775nW時，其值為31.2%。

關鍵字

能量擷取 ； 電壓轉換器 ； 最大功率點追蹤

並列摘要

This thesis consists of two parts. The first part implements a wide input power range self-oscillating switched-capacitor DC-DC converter. By introducing the self-oscillating mechanism into the switched-capacitor converter (SCC), the extra oscillator for generating periodic switch control signals can be omitted to reduce power consumption. The SCC is multi-layered with an operation similar to a Dickson charge pump (DCP), and can therefore reduce the losses from parasitic capacitors under a wide input power range. The measured input power range is from 33.9nW to 851μW, and the peak power conversion efficiency (PCE) is 47.9%.
The second part implements an indoor photovoltaic energy harvester based on the SCC above. It also implements a maximum power point tracking (MPPT) function for maximizing the input power from solar cells. The MPPT function is based on the fractional open circuit voltage (FOCV) method but works without the input power switch. It avoids disconnecting the converter when sampling the open circuit voltage of solar cells, and also eliminates the need to trade off between conduction loss and gate driving loss when designing the input power switch. The system is fabricated in 0.18μm CMOS process and its active area is 0.86mm2. The total PCE from the solar cell to output is around 30% with a peak value of 31.2% that occurs when the cell provides 775nW for maximum power.

並列關鍵字

energy harvester ； DC-DC converter ； maximum power point tracking

參考文獻

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