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。
在本論文中採用電流平均模式控制的方法，並利用OrCAD PSpice電子電路模擬軟體來建模分析，使系統的達到理想的穩壓控制並且提高系統的功率因數。最後，利用吾人所建立的電流平均模式控制模型，應用在並聯式電源供應器的功率因數修正上，藉由軟體的分析與模擬，提出在超過額定負載法下所設計的並聯式電源供應器中，其最佳化的操作範圍與功率因數的修正結果，

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.
In this thesis, average current control mode has been employed for simulating the complete power circuits with the help of EDA software, namely Pspice, on analyzing circuits and modeling devices such that stability and high power factor can be achieved. Moreover, the paralleling of power supplied has been studied for correcting the power factor with optimized operational regions under power overload conditions. The results are promising for the future applications of simulation in PFC circuits.

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