【摘要】：實現(xiàn)電源的“綠色化”,減小諧波污染和電磁干擾,已成為電源研發(fā)設(shè)計的一個基本要求。在電源系統(tǒng)中引入功率因數(shù)校正技術(shù)可以有效地提高輸入功率因數(shù),降低諧波電流對電網(wǎng)的污染,以保證電網(wǎng)的供電質(zhì)量,避免諧波干擾。在目前功率因數(shù)校正技術(shù)的研究中,其核心問題即為如何實現(xiàn)高效率、高功率因數(shù)和高功率密度。常規(guī)采用單相PFC技術(shù)的各類電氣設(shè)備中,通常采用整流橋先將交流電轉(zhuǎn)化為脈動的直流電,再經(jīng)過PFC變換器實現(xiàn)功率因數(shù)校正功能。隨著變換器功率等級的不斷提高,整流橋的損耗在變換器整體損耗中所占的比例越來越大,嚴重影響了變換器效率的提升。因此,無輸入端整流橋的無橋PFC變換器因為高效率成為了人們關(guān)注的焦點。本文首先分析了電感電流斷續(xù)模式下基本型無橋Boost PFC變換器的工作原理,并對其電路特性進行了詳細的數(shù)學(xué)推導(dǎo)。通過理論分析發(fā)現(xiàn),定頻定占空比控制下的斷續(xù)無橋Boost PFC變換器雖然具有控制簡單、功率器件開關(guān)損耗較小等優(yōu)點,但在輸入輸出電壓比值較大時功率因數(shù)較低。基于以上理論分析,本文設(shè)計了一臺500W的樣機并進行了實驗驗證,實驗結(jié)果證明了無橋PFC拓撲高效率的優(yōu)點,樣機最高效率達98.5%,隨著輸入電壓的增加,網(wǎng)側(cè)電流波形畸變,功率因數(shù)下降明顯。為了改善斷續(xù)模式下變換器功率因數(shù)較低的缺點,本文通過對理想占空比的擬合計算,提出了一種較為簡單的變占空比控制策略。與定占空比控制相比,本文所采用的方法可以有效提高輸入功率因數(shù),減小輸入電流紋波,同時保證變換器高效率的優(yōu)點。在此基礎(chǔ)上,本文完成了一臺變占空比控制500W樣機的實驗驗證,實驗結(jié)果驗證了該控制方法的有效性。斷續(xù)模式下的PFC變換器電壓電流應(yīng)力大,一般僅適用于中小功率場合。為了適應(yīng)更大的功率需求,擴大斷續(xù)模式無橋PFC變換器的應(yīng)用場合,本文將交錯并聯(lián)技術(shù)引入無橋Boost PFC變換器,分析了電感電流斷續(xù)模式下兩路交錯并聯(lián)無橋Boost PFC變換器的工作原理和電路特性,并在理論分析的基礎(chǔ)上完成了一臺1kW的樣機實驗。由于變換器中功率器件存在寄生參數(shù)、電感存在非線性等非理想因素,影響變換器的工作特性。論文通過詳細的數(shù)學(xué)分析和討論,研究了電路中典型非線性因素對變換器特性的影響。本文首先考慮功率器件的寄生參數(shù),討論了變換器的工作特性,分析了其參數(shù)大小與電流畸變的數(shù)學(xué)關(guān)系,并通過仿真驗證了理論分析的正確性。其次,本文采用回轉(zhuǎn)器-電容模型對變換器中的非線性電感進行了數(shù)學(xué)建模,給出了詳細的模型參數(shù)計算方法,并進行了仿真驗證。
[Abstract]:The realization of "green" power supply and the reduction of harmonic pollution and electromagnetic interference have become a basic requirement of power development and design. The introduction of power factor correction technology in power supply system can effectively improve the input power factor and reduce the pollution of harmonic current to the power network so as to ensure the power supply quality and avoid harmonic interference. In the current research of power factor correction, the key problem is how to achieve high efficiency, high power factor and high power density. In the conventional single-phase PFC technology, rectifier bridge is usually used to convert AC to pulsating DC first, and then to realize power factor correction through PFC converter. With the continuous improvement of the power level of the converter, the loss of the rectifier bridge accounts for more and more of the overall loss of the converter, which seriously affects the efficiency of the converter. Therefore, no input rectifier bridge without bridge PFC converter because of high efficiency has become the focus of attention. In this paper, the working principle of the basic bridge free Boost PFC converter in the intermittent mode of inductance current is analyzed, and the circuit characteristics of the converter are derived in detail. Through theoretical analysis, it is found that the intermittent non-bridge Boost PFC converter with fixed frequency and duty cycle control has the advantages of simple control and low switching loss of power devices, but the power factor is lower when the ratio of input and output voltage is high. Based on the above theoretical analysis, a 500W prototype is designed and verified by experiments. The experimental results show that the bridge free PFC topology has the advantages of high efficiency. The maximum efficiency of the prototype is 98.5. With the increase of input voltage, the grid-side current waveform is distorted. The power factor decreased obviously. In order to improve the low power factor of the converter in intermittent mode, a simple variable duty cycle control strategy is proposed by fitting the ideal duty cycle. Compared with the constant duty ratio control, the proposed method can effectively improve the input power factor, reduce the ripple of input current and ensure the high efficiency of the converter. On this basis, an experimental verification of a 500W prototype with variable duty cycle control is carried out, and the effectiveness of the control method is verified by the experimental results. The voltage and current stress of PFC converter in intermittent mode is large, and it is only suitable for medium and low power situations. In order to meet the greater power demand and expand the application of intermittent mode non-bridge PFC converters, this paper introduces the staggered parallel technology into bridge-less Boost PFC converters. The working principle and circuit characteristics of two staggered parallel bridge free Boost PFC converters in intermittent inductance current mode are analyzed. Based on the theoretical analysis, a prototype experiment of 1kW is completed. Because of the parasitic parameters of power devices and the nonideal factors such as the nonlinearity of inductors, the operating characteristics of the converters are affected. Through detailed mathematical analysis and discussion, the influence of typical nonlinear factors on converter characteristics is studied in this paper. In this paper, the parasitic parameters of power devices are considered, and the working characteristics of the converter are discussed. The mathematical relationship between the parameters and the current distortion is analyzed, and the correctness of the theoretical analysis is verified by simulation. Secondly, the nonlinear inductance in the converter is modeled by the gyralizer-capacitance model, and the detailed calculation method of the model parameters is given and verified by simulation.
【學(xué)位授予單位】：南京航空航天大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：TM46

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本文編號：2193939