300瓦順向式電源供應器功因修正及電磁干擾防制設計與實作

近幾年中，隨著電腦以及操作機台的快速發展，電源供應器所需提供的單位體積功率密度的需求越來越高，並且對高效率的要求也越來越高。然而電路中產生的電流諧波以及負載相位不同的問題，不但產生許多雜訊對控制系統的穩定性造成影響，更會降低電源供應器的功率因數導致能源的浪費。因此提高切換式電源供應器的功因是目前世界各國一致的目標，也是各個電源供應製造商努力的動機。本研究主旨在於討論功因修正器之設計，針對其種類及控制策略進行分析與比較，並以升壓型轉換器作為主電力電路架構，採用固定切換頻率及平均電流控制模式，以降低輸入電流諧波，並使輸入電流與電壓同相，達到修正功因的目的。最後，使用ML4800作為控制IC，實作出有PFC功能的300瓦順向式電路，實驗結果驗證了所採控制技術之正確性與可行性，在滿載時可達0.95。除此之外，本論文為了解決在交換式電源供應器應用之中所產生的傳導性電磁干擾問題，在電路前端加入二階濾波器，來分析不同雜訊來源之應對策略，作為未來實測之參考。

關鍵字

平均電流模式；功因修正；電磁干擾

並列摘要

The fast developments of high-level computers and operating machine platforms have promoted the demands for switch-mode power supplies with high energy density and efficiency recently. However, the problem due to the harmonic current in the circuit and different load phase would not only affect the stability of the switch-mode power circuits but also deteriorate the power factor with more energy losses. Thus, how to improve the power factor of switch-mode power supplies has been the common goal in the industry. This report is focused on the design and implementation of a power factor corrector (PFC). Various types of PFC topologies and several control schemes are also discussed. The set-up converter by the average current mode control with a constant switching frequency is proposed. The main objective is to reduce the input current harmonics and to increase the power factor to approaching one. At last, a 300W Forward PFC prototype is manufactured based on the ML4800 control IC to be the test board. The experimental results confirm the validity and feasibility of the adopted scheme. The PF value can be higher than 0.95 when it operated in fully loading. In addition, this report presents the steps for solving the conducted EMI problems for switching power supply. A second-order passive filter is put in front of the switch power supply circuit to indicate the EMI element’s functions for different source of noise. The result would be a reference for the EMI test in the further.

並列關鍵字

average current mode control. ； EMI ； power factor corrector (PFC)

參考文獻

【22】范振朝，交換式電源供應器之電磁干擾濾波器設計方法，碩士學位論文，中原大學，民國九十五年六月.

【45】王梓鋼，順向式DC-DC電源轉換器之T-S模糊控制設計，碩士學位論文，中原大學，民國九十三年七月。

【2】 B. Wilkerson, “Power Factor Correction and IEC 555-2,” Power Technics Magazine, pp. 20-24, 1991.

【3】 R. Srinivasan and R. Oruganti, “A single phase parallel power processing scheme with power factor control,” Power Electronics and Drive Systems of IEEE, Vol. 1, pp. 40 – 47,1995.

【5】 J. Spangler and A. K. Behera, “Power factor correction techn -iques used for fluorescent lamp ballasts,” Industry Applications Society Annual Meeting of IEEE, Vol. 2, pp. 1836 – 1841, 1991.

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300瓦順向式電源供應器功因修正及電磁干擾防制設計與實作

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