本論文比較三柱對稱型、四柱對稱型以及三柱非對稱型三種磁整合變壓器，藉由數學分析上述三種變壓器之磁路、磁通，並比較三種磁性元件磁通耦合狀況，以此評估三柱非對稱型耦合鐵芯是否能取代其它兩種變壓器的可行性。並用三柱非對稱型耦合變壓器實現三相Why-Delta串聯諧振式電路。變壓器的部分則是以增加氣隙的方式來降低激磁電感使初級側開關零電壓切換，次級側則是利用同步整流的技術減少導通損失。最後完成2200瓦，400伏特轉12伏特且滿載效率高達90.04%直流對直流轉換器。

This thesis aims to compare the three kinds of integrated transformers, the symmetrical three-legs, symmetrical four-legs and non-symmetrical three-legs. Analyze the magnetic circuit and integrated flux by the mathematics. Compare the integrated condition when the three kinds of magnetic components occur the flux integrated. Evaluate the non-symmetrical three-legs core whether replace the others, and use non-symmetrical three-legs transformer to implement three-phase Wye-Delta series resonant circuit. In transformer, this thesis increased air gap to reduce the value of magnetizing inductance. In order to make the primary side switch achieve zero-voltage switch. Reduce the conduction loss of secondary by synchronous rectification.
Finally, 2.2 kw, 400 V to 12 V, full-load efficiency 90.03% high power density server power supply is implemented.

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