發(fā)布時間：2019-01-25 21:15

【摘要】：為減小AC/DC變換器等電子設備給電網帶來的諧波污染,功率因數校正技術(Power Factor Correction, PFC)得到了廣泛應用。工作于不連續(xù)導電模式(Discontinuous Conducting Mode, DCM)的Flyback PFC變換器具有效率高、成本低、結構簡單、功率因數高、輸入-輸出電氣隔離等優(yōu)點而得到廣泛應用。傳統(tǒng)單級Flyback PFC變換器存在二倍工頻紋波、負載瞬態(tài)響應慢等缺點,限制其應用范圍。本文以DCM Flyback PFC變換器為例,研究了引入Buck變換器補償二倍工頻紋波,以消除DCM Flyback PFC變換器輸出的二倍工頻紋波的技術。論文研究了Buck補償DCM Flyback PFC變換器的工作原理、主要工作波形和控制策略,建立了變換器的等效模型,分析了其直流穩(wěn)態(tài)和交流小信號特性；研究了實現(xiàn)低輸出電壓紋波的條件；且對比了本文所研究的變換器、單級DCMFlyback PFC變換器和DCM Flyback PFC變換器級聯(lián)Buck變換器三種變換器之間的效率；此外還推導了Flyback PFC變換器和Buck變換器工作于DCM模態(tài)下臨界電感。以理論分析為基礎,搭建一臺48V/50W的實驗樣機。論文介紹了恒壓式電壓型控制Buck補償DCM Flyback PFC變換器設計步驟；詳細分析了變壓器的設計和控制環(huán)路的設計以及參數的選�。唤榻B了實驗中功率電路等具體使用參數；通過實驗,驗證理論分析的正確性。實驗結果表明：Buck補償DCM Flyback PFC變換器不僅實現(xiàn)輸出電壓低紋波,且具有快速的負載瞬態(tài)響應速度。通過改變控制策略,實現(xiàn)Buck補償DCM Flyback PFC變換器的恒流輸出。論文介紹了恒流式Buck補償DCM Flyback PFC變換器工作原理和主要工作波形；詳細研究了其控制策略；推導了變換器實現(xiàn)低輸出電流紋波控制器應滿足的條件；詳細介紹了變換器恒流輸出時控制器的設計。最后研制了一臺0.7A/50W的實驗樣機。通過實驗樣機,驗證了理論分析的正確性和Buck補償DCM FlybackPFC輸出二倍工頻紋波的可行性。
[Abstract]:In order to reduce harmonic pollution caused by electronic devices such as AC/DC converters, power factor correction (Power Factor Correction, PFC) technology has been widely used. The Flyback PFC converter operating in discontinuous conductive mode (Discontinuous Conducting Mode, DCM) is widely used because of its advantages of high efficiency, low cost, simple structure, high power factor and electrical isolation between input and output. The traditional single-stage Flyback PFC converter has the shortcomings of double power frequency ripple and slow transient response of load, which limits its application scope. Taking DCM Flyback PFC converter as an example, this paper studies the technique of introducing Buck converter to compensate double power frequency ripple in order to eliminate the double power frequency ripple output from DCM Flyback PFC converter. In this paper, the working principle, main working waveform and control strategy of Buck compensated DCM Flyback PFC converter are studied, the equivalent model of converter is established, the characteristics of DC steady state and AC small signal are analyzed, the condition of realizing low output voltage ripple is studied. The efficiency of the three converters, single stage DCMFlyback PFC converter and DCM Flyback PFC cascade Buck converter, are compared, and the critical inductance of Flyback PFC converter and Buck converter working in DCM mode is deduced. Based on theoretical analysis, an experimental prototype of 48V/50W is built. This paper introduces the design steps of Buck compensated DCM Flyback PFC converter with constant voltage mode control, analyzes the design of transformer, the design of control loop and the selection of parameters in detail, and introduces the power circuit in the experiment. The correctness of the theoretical analysis is verified by experiments. The experimental results show that the Buck compensated DCM Flyback PFC converter not only achieves low ripple output voltage, but also has a fast load transient response speed. By changing the control strategy, Buck compensates the constant current output of DCM Flyback PFC converter. This paper introduces the working principle and main working waveform of constant current Buck compensated DCM Flyback PFC converter, studies its control strategy in detail, deduces the conditions that the converter should satisfy to realize the low output current ripple controller. The design of constant current output controller of converter is introduced in detail. Finally, an experimental prototype of 0.7A/50W is developed. The correctness of the theoretical analysis and the feasibility of Buck compensating DCM FlybackPFC output double power frequency ripple are verified by the experimental prototype.
【學位授予單位】：西南交通大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TM46

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本文編號：2415195