高功因隔離式SEPIC電力轉換器之分析與研製

Analysis and Implementation of an Isolated SEPIC Converter with High Power Factor Correction

林華偉(Hua-Wei Lin)

指導教授 ： 陳信助

崑山科技大學/工程學院/電機工程研究所/碩士(2008年)

https://doi.org/10.6828/KSU.2008.00041

摘要

本文探討以隔離式SEPIC電力轉換器作為AC-DC高功因前置穩壓器。當轉換器操作在DCM(L1>L2)模式下，不需要額外的電流控制電路，天生具有高功因的特性，配合輸出電壓回授控制，可使隔離式SEPIC電力轉換器具有高功因、電氣隔離和輸出穩壓等性能。
穩態時，根據切換開關和二極體的導通狀態，一個切換週期可分成三個線性階段作為電路動作分析，以得到電路元件的電壓或電流波形，再依據電力轉換器的規格要求，設計實作元件的數值，最後利用IsSpice模擬軟體，驗證電路分析的正確性。
在輸出穩壓方面，以雙時間尺度平均化法和電流注入等效電路法推導隔離式SEPIC電力轉換器之小信號數學模式，兩種方法所推導的結果一致，並且使用動態信號分析儀量測頻率響應，以驗證模式推導的正確性。最後利用古典控制理論設計穩壓控制器，使輸出電壓不受輸入電壓變動或負載變動的影響，達成穩壓的性能。為了進一步改善負載變動時輸出電壓的響應性能，在電路中加入負載電流注入控制法，使得負載變動時輸出電壓能更快達到穩壓的效果。
在實作成果中，研製了一組輸入電壓AC110V，輸出電壓DC48V，切換頻率50kHz最大輸出功率100W的隔離式SEPIC電力轉換器，由實作結果驗證此電力轉換器確實具有高功因和輸出穩壓的性能。

關鍵字

高功因 ； 隔離式SEPIC電力轉換器 ； 雙時間尺度平均化法

並列摘要

The isolated SEPIC converter working as a high-power-factor preregulator is studied in this thesis. The converter exhibits high power-factor inherently without extra current control when it operates in DCM(L1>L2) mode. The converter exhibits the desirable characteristics including input-output isolation, theoretical unity power factor, and well output voltage regulation when it is well output feedback control design.
The converter can be divided into three linear stages in one switching period for circuit analysis when it in operates in the steady state. The IsSpice simulation is used to verify the theoretical analysis after the components design.
The two-time scale averaging method and current injected equivalent circuit approach are used to derive the small signal model. They obtain the coincide results. The mathematical models are verified by the experimental measurements of the dynamic signal analyzer. Eventually, a controller is designed to eliminate the effect of the variations in line voltage and load on the output voltage. Furthermore, the load current injected control is employed to improve the output voltage response when the load is step change.
A prototype of the converter with an input voltage of AC110V, an output voltage of DC48V, operating at a switching frequency of 50kHz and maximal power 100W is implemented. The performances of high power-factor and well output voltage regulation are verified by experimental measurements.

並列關鍵字

high power factor ； isolated SEPIC converter ； two-time scale averaging method

參考文獻

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