Abstract
本論文之主要目的在於研製一具有升降壓及功因控制之軟式切換蓄電 池充電器。首先探究蓄電池之充、放電特性，並據以研擬合適之充電命令 及充電狀態判別法則，以不損蓄電池之使用壽命。在充電器電力電路及其 控制方面，研製一具有可於交流輸入電壓之半週期內，依電源電壓大小可 分別操作於升壓或降壓模式之降壓－升壓串接型切換式整流器，使輸出電 壓範圍較為寬廣，以利串接電池組之充電。此切換式整流器於各個操作模 式下之工作原理、等效電路及主導方程式將於論文中有詳細之推導，並據 以研擬一系統化電路設計步驟。為了方便控制器之設計，所提整流器之動 態模式亦詳予推導，藉由巧妙之電流強迫控制，可使整流器之線電流波形 為含低諧波成分之弦波，且功因接近１。然後應用所研擬之蓄電池狀態判 別及充電命令，配合所提之充電控制器可對蓄電池做較佳之充電控制。 接著本論文亦從事軟式切換共振充電器之研製，以減少開關元件之切 換損失及應力，進而提高整體之效率。所提軟式切換機構簡易，只要在原 有降壓－升壓串接型切換式整流器之主開關配接輔助共振電路，藉由對主 開關及輔助開關之適當延遲觸發控制，即可達成軟式切換而不影響原切換 控制效能，不需額外加裝電壓及電流感測器。本論文中所設計之轉換器及 控制器均先經Pspice軟體模擬確認其可行性後，再從事實際電路製作，並 以一些實測結果再加以驗證。 The major purpose of this thesis is to develop a soft- switching battery charger with step up/down voltage and power factor correc- tion control. First, the charging and discharging characteristics of battery are investigated, and accordingly, the suitable charg- ing command and the criterion for identifying the charging status are proposed to reduce the detrimental effects on the battery cy- cle life. Then a battery charger consisted of a cascade buck-boost switch mode rectifier is developed. Depending on the output volta- ge level, this rectifier can be operated in buck or boost mode in each ac half cycle. It follows that wider range output voltage and hence larger charging flxibility for serially connected batteries are obtained. The circuit operations equivalent circuits and gove- rened equations in various operation modes of the rectifier are detailedly analyzed. According to the analysis results, a syste- matic design procedure is developed to design the rectifier compo- nents. In addition, the dynamic model of the proposed rectifier is derived. Then accordingly, the inner-loop current-foced switching controller is designed, such that sinusoidal line current with low harmonics and nearly unity power factor is obtained. And the outer loop charging controller is also designed for yielding good dyna- mic charging characteristics. Finally, an easily-implemented soft-switching mechanism is deve- loped to significantly reduce the switching losses and stresses of the power switches. The soft-switching control can be successfully achieved by simply adding the auxiliary soft - switching resonant circuit to the original cascade buck - boost switch mode rectifier with suitable delayed switching control singals. The analysis and design of the proposed soft switching mechanism are also made. After confirming the validity of the designed battery charger by simulations, the circuit implementation is performed, and some measured results are provided for further demonstrating its per- formance.