臺灣博碩士論文加值系統

　　本論文主要在探討功率型金氧半場效電晶體(Power MOSFET)之並聯方式及其保護電路，並應用於不斷電電源系統(UPS)上，以增加不斷電電源系統之容量。
　　簡易的功率型金氧半電晶體並聯技術，在其源極各加一回授電阻，使電流達到均流的目的；但相對地消耗在回授電阻的功率損失非常大，並不適用於大電流系統。為改善此一問題，本文提出電流感測元件，將開關電流經電流轉換器轉換成電壓訊號，藉此訊號調變閘極電壓值以達到均流之目的，並減少功率的損失。本文並設計保護電路以抑制使用時所產生之過電流及電壓突波，對功率型金氧半場效電晶體作適當的保護。
　　最後，建立一個IKVA的換流器硬體雛型，求驗證此電流迴授架構應用於UPS上的可行性。

　　In this thesis, the parallel and protective methods of power MOSFET are investigated, and this method is applied on uninterrupted power supply (UPS) to enhance its power capacity.
　　In simple parallel method of power MOSFET, a feedback resistor is connected in series to the source terminal of power MOSFET. Although it makes the current balanced, the power loss is increased opposite and this method is unsuitable applied the systems of large current. In order to overcome this drawback, a new structure using current feedback method is proposed. In this method, a current transducer is applied to transfer the switch current to voltage signal, which used to adjusted the gate-source voltage of power MOSFET. Not only the switch current in parallel are balanced, the power loss in feedback circuit is decreased. Moreover, to prevent the damage from over current and voltage surge to power MOSFET, wer designed a protective circuit to suppress the over current and voltage surge.
　　Finally, two parallel MOSFETs are applied to a lkVa inverter to demonstrate the performance of the proposed scheme.