- 學位論文
利用Primary回授設計OFF-LINE返馳式開關轉換調節器應用在醫療用電源供應器之研製
Design of an Off-line Flyback Switching Converter Regulator Using Primary Feedback for Medical Desktop Power Supply
摘要
近幾年中，隨著高階電腦的快速發展，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；為了因應這些需求，應用在高頻操作下的切換式電源供應器以幾乎完全取代了傳統的線性電源供應器，然而在電源供應器中的切換元件高速動作下，輸入電流的弦波訊號經過高頻切換變為脈衝訊號，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率因數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。 本論文提出以Primary回授技術，進行OFF-LINE返馳式開關轉換調節電路之研製。電路本身不需要作電氣隔離，在設計上使用變壓器作電氣隔離與電壓準位的調整。返馳式轉換器的電路架構，是具有隔離特性的升降壓型轉換器，該變壓器不是磁性元件的功能，而係利用耦合電感達到能量轉換的目的，設計整個電路的重點是磁能的儲存與釋放。本論文返馳式轉換器的電路，傳遞能量機制是耦合電感，不是真正的變壓器，鐵芯需要有適當的氣隙存在，防止飽和和平衡直流成分。控制迴路是採用電壓負迴授方式，來獲得良好的電壓調節，完成一個輸入90V到253V交流電壓，輸入頻率範圍47Hz到63Hz，輸出則是一組＋16.5V到＋19.5V的直流電壓，輸出功率為13瓦特，負載範圍0A到0.7A之OFF-LINE返馳式開關轉換調節器之研製。
並列摘要
The fast development of high-level computers has promoted the growing demands for switch-mode power supplies with high energy density and efficiency recently. Hence, the switch-mode power supplies operated at high frequency have evidently dominated over the conventional linear power supplies. However, sinusoidal ac currents chopped by the high speed switching devices into current pulses would not only affect the stability of the circuits but also deteriorate the power factor with more energy losses. Thus, the improvement on the power factor of switch-mode power supplies has been the common goal and incentive in the industry. This thesis is bringing up a research and produce of primary feedback, OFF-LINE flyback switching converter regulate the circuit. The circuit itself is not need to do electricity isolated, using transformer to control electricity isolated and voltage standards in design. Flyback converter’s circuit frame is an ascended and step-down transformer that with electricity isolated characteristic. The transformer is not a magnetism component function, it is to utilize coupled inductance for switching energy purpose, and the most important points in whole circuit design are magnetic capacity storage and release. In flyback converter’s circuit, to send energy is by coupled inductance not by the transformer. The ferrite cores have to keep appropriate air gap to avoid saturation and balance direct currents. It is to use voltage go back mode to control circuit loop, and to obtain fine voltage regulated. Completed one OFF-LINE flyback converter research that is input 90V-253V AC voltages, input frequency range 47Hz-63Hz, output +16.5V-+19.5V DC voltages, output power 13W, load range 0A-0.7A.