- 學位論文
新型零電流切換並聯負載共振式轉換器
A Novel Parallel-Loaded Resonant Converter with Zero-Current-Switching Scheme
摘要
傳統脈波寬度調變(Pulse Width Modulation；PWM)電力轉換器具有嚴重的電磁干擾(Electromagnetic Interference；EMI)及散熱問題，且開關必須承受很高的切換應力(Switching Stress)和高切換損失等缺點，使得轉換器無法有效的操作在高頻環境中，轉換效率的提升面臨瓶頸。為了解決這些缺點，可以利用具有柔性切換特性之共振式轉換器來做改善，共振式轉換器會依據共振槽與負載連接方式的不同，而產生不同的共振形式與效果，藉由選擇適當的元件參數，以及調整開關之切換頻率，可使開關在高頻環境中操作於零電壓切換(Zero Voltage Switching；ZVS)或零電流切換(Zero Current Switching；ZCS)狀態，降低開關的切換損失，並提高轉換器的效率。 本論文所提出的新型零電流切換並聯負載共振式轉換器，主要是以E類共振式換流器為基本電路架構，並將其加以改良設計而成。由於只需利用單一開關進行切換，與利用雙開關切換的D類共振式換流器相較之下，不但可以減少一個開關的切換損失，亦提高了整體的轉換效率。新型零電流切換並聯負載共振式轉換器除了具有柔性切換的特性，同時還擁有昇壓的特性，並且在輸出端加入橋式整流器與濾波器電路，使得輸出端能有穩定的直流電壓與電流輸出，此種轉換器電路具有結構簡單、低成本及高轉換效率等優點。最後經由硬體電路實際量測之結果，證實本論文所提出的新型零電流切換並聯負載共振式轉換器可達到96%以上的高轉換效率。
並列摘要
Serious electromagnetic interference (EMI) and cooling problems have been found in the traditional pulse width modulation (PWM) electronic converter. Moreover its switch has to receive a high level of switching stress and the defect of such a high switching losses which made the converter could not operate effectively in high-frequency environment, the raise in conversion efficiency has been facing the bottlenecks. In order to solve these shortcomings, the features of soft-switching in resonant converter, which can be used to do the improvement. The resonant converter will follow up the different connection ways of resonant slot and load, and produce different resonant forms and effects. By selecting appropriate component parameter, and adjusting the switching frequency, which enabled the switch in high frequency environment is easy to operate under the state of zero voltage switching (ZVS) or zero current switching (ZCS), to reduce the switching losses as well as to enhance the efficiency of the converter. This thesis proposed a novel parallel-loaded resonant converter with zero-current-switching scheme, which mainly uses class-E resonant inverter as basic circuit structure and then reinforced its design accordingly. Because of its function only with a single switch, as compared to use two switches of class-D resonant inverter, it not only can reduce the switching losses of a switch, but also increases the overall conversion efficiency. In addition to the characteristics of soft-switching, a novel parallel-loaded resonant converter with zero-current-switching scheme also owns a boosting characteristics. Furthermore, when adding the bridge rectifier and filter circuit to the output end, which makes the outputs end having stable DC voltage and current output. In general, this converter circuit has the advantages of a simple structure, the low cost and high conversion efficiency. The results is conducted through an actual measurement on hardware circuit, and experimental results that the high conversion efficiency of a novel parallel-loaded resonant converter with zero-current-switching scheme can be up to 96% in the final experiment.