零偏移電流之非對稱隔離式半橋LED調光驅動電路設計

本文提出一零偏移電流之非對稱隔離式半橋LED驅動電路，其電路架構由升壓式轉換器與半橋轉換器拓樸而成之單級功因修正電路，本文所提出之電路架構透過平衡電容解決傳統非對稱半橋轉換器的變壓器電流偏移問題。本論文利用功因修正電感電流峰值隨著電源電壓變化，達到主動功因修正的目的，並將功因修正電感電流操作於不連續導通模式，降低功率開關觸發設計的困難度。本論文利用變壓器的激磁電感使功率開關具有零電壓切換的特性，有效減少功率開關切換所造成的損失，並採用非對稱式脈波寬度調變技術調整輸出功率，達到大範圍調光之目的。本文透過電路分析與數學推導，並實際設計與製作115瓦(96V/1.2A)LED驅動電路，透過電路波形與量測結果驗證本文之推論與可行性。經實驗結果本文所提出之驅動電路滿載轉換效率90.7%；功率因數最高可達0.994，且於任何責任週期下變壓器零電流偏移。

關鍵字

發光二極體；非對稱半橋轉換器；變壓器電流偏移；平衡電容；零電壓切換

並列摘要

This paper proposes an asymmetrical half-bridge isolated dimmable LED driver with zero dc-offset current which features a single-stage PFC circuit integrated topologically by a boost converter and a half bridge converter. The developed circuit overcomes the inherited dc-offset current of transformer in a conventional asymmetrical half-bridge converter by introducing a balance capacitor. This paper utilizes the amplitude of power factor correction inductor current varies with the input voltage, which achieves power factor correction. The proposed circuit of this paper is operated in discontinuous conduction mode. Discontinuous conduction mode can reduce designed difficulties. To achieve zero voltage switching of power switch, this paper uses magnetizing inductance of the transformer. The zero voltage switching can reduce switching loss. This paper uses to asymmetrical pulse width modulation technology, which achieve wide-range dimming. In this thesis, the circuit analysis and mathematical derivation, a 115 W (96V/1.2A) LED driver circuit is designed and implemented. The practical measurement and waveform analysis disclose the feasibility of the proposed circuit. Finally, the developed LED driver possesses 90.7% full-load conversion efficiency and 0.994 power factor, along with zero dc-current offset under any duty cycle.

並列關鍵字

Light Emitting Diode ； Asymmetrical half-bridge converter ； Transformer current DC offset ； Balance capacitance ； Zero-voltage switching

參考文獻

[29] 黃登群，2014，“單級高功因全橋諧振式LED驅動電路研製”，虎尾科技大學電機工程學系碩士論文

[9] 鐘世彥，2006，“單級高功因LED燈驅動器之研製”，中原大學電機工程學系碩士論文

[2] Chun-An Cheng, Hung-Liang Cheng, Tsung-Yuan Chung, 2014, “A Novel Single-Stage High-Power-Factor LED Street-Lighting Driver With Coupled Inductors”, IEEE Transactions on Industry Applications, Vol.50, pp.3037-3045, February.

[3] Qian Wang, Tao Li, Qian-Hua He, 2014, “Dimmable and Cost-Effective DC Driving Technique for Flicker Mitigation in LED Lighting”, Journal of Display Technology, Vol.10, pp. 766-774, April.

[4] M. S. Roedgaard, M. Weirich, M.A.E. Andersen, 2012, “Forward Conduction Mode Controlled Piezoelectric Transformer-Based PFC LED Drive”, IEEE Transactions on Power Electronics, Vol.28, pp. 4841-4849, December.

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零偏移電流之非對稱隔離式半橋LED調光驅動電路設計

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