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  本文選題：寬范圍輸出 + ZVS軟開關(guān)　； 參考：《哈爾濱工業(yè)大學(xué)》2015年碩士論文

【摘要】：在電動汽車充電系統(tǒng)中,前級PFC(Power Factor Correction)裝置輸出電壓范圍有限,需要中間級DC-DC變換器才能滿足充電需求。移相全橋拓?fù)浜唵�、開關(guān)損耗小、可靠性高,是一種適合于大中功率場合的軟開關(guān)拓?fù)�。本文主要對寬范圍輸出的副邊移相控制全橋變換器進(jìn)行研究。對各種移相全橋拓?fù)溥M(jìn)行了充分的分析研究之后,本文提出了一種帶有無源輔助網(wǎng)絡(luò)的副邊移相控制全橋變換器。此變換器拓?fù)錈o需箝位電路就消除了整流二極管電壓尖峰,提升了器件的可靠性;輸出電容復(fù)位原邊電流,消除原邊續(xù)流損耗;引入副邊移相控制策略,實現(xiàn)了副邊二極管的ZCS(Zero Current Switch)自然換流;無源輔助網(wǎng)絡(luò)的加入使得變換器原邊開關(guān)管在空載條件下也能實現(xiàn)ZVS(Zero Voltage Switch)軟開關(guān),降低了開關(guān)損耗,提高了變換器效率。本文建立了移相角與變換器功率及輸出電壓的數(shù)學(xué)模型,并且論述了軟開關(guān)條件,對電路參數(shù)與輸出特性、軟開關(guān)條件的關(guān)系進(jìn)行了探討。通過對比所有工作狀態(tài),可知DCM(Discrect Conduct Mode)工作狀態(tài)回流功率為0,選擇DCM工作狀態(tài)作為變換器的主要工作狀態(tài)。通過對移相電感、無源輔助網(wǎng)絡(luò)等電路參數(shù)的優(yōu)化設(shè)計,使變換器運行于所設(shè)定的工作狀態(tài),開關(guān)管在寬負(fù)載范圍下實現(xiàn)ZVS軟開關(guān)。利用開關(guān)周期平均法對變換器進(jìn)行小信號建模,比較了二階與一階小信號模型,并在一階小信號模型的基礎(chǔ)上,設(shè)計合理的補償網(wǎng)絡(luò)和閉環(huán)系統(tǒng)控制電路,確保閉環(huán)系統(tǒng)穩(wěn)定工作并且兼顧控制系統(tǒng)快速性。通過仿真和實驗對本文的研究內(nèi)容進(jìn)行驗證。制作了一臺輸入電壓100 V,輸出電壓200 V-400 V,頻率100 k Hz的實驗樣機(jī),測試了所有工作狀態(tài)下原邊電感電流波形,驗證了理論分析及仿真結(jié)果。其次在DCM工作狀態(tài)下,驗證了輸出電壓為200 V和400 V的不同載荷下的原副邊開關(guān)管軟開關(guān)特性。最后驗證了切載時閉環(huán)控制系統(tǒng)的穩(wěn)定性和快速性。實驗結(jié)果達(dá)到預(yù)期設(shè)計目的及指標(biāo)。
[Abstract]:In the electric vehicle charging system, the output voltage range of the front stage PFC(Power Factor correction device is limited, so the intermediate stage DC-DC converter is needed to meet the charging requirements.The phase-shifting full-bridge topology is simple, the switching loss is small, and the reliability is high. It is a soft switching topology suitable for large and medium power situations.In this paper, a wide range of output side-shift control full-bridge converter is studied.After a full analysis of various phase-shifted full-bridge topologies, this paper presents a kind of auxiliary side-shift full-bridge converter with passive auxiliary network.The converter topology eliminates the voltage spike of the rectifier diode without clamping circuit and improves the reliability of the device; the output capacitor resets the primary current to eliminate the current loss of the original side; and the secondary side phase shift control strategy is introduced.The natural commutation of ZCS(Zero Current switch of secondary side diode is realized, and the addition of passive auxiliary network makes the ZVS(Zero Voltage switch soft switch under the condition of no load, which reduces the switching loss and improves the efficiency of the converter.In this paper, the mathematical model of phase shift angle, converter power and output voltage is established, and the soft switching conditions are discussed. The relationship between circuit parameters and output characteristics, soft switching conditions is discussed.By comparing all the working states, it is known that the reflux power of DCM(Discrect Conduct mode is 0, and the working state of DCM is chosen as the main working state of the converter.By optimizing the circuit parameters such as phase-shifted inductor and passive auxiliary network, the converter runs in the set working state, and the switching tube realizes the ZVS soft switch in the wide load range.The switching cycle averaging method is used to model the converter with small signal. The second order and first order small signal models are compared. On the basis of the first order small signal model, a reasonable compensation network and closed-loop system control circuit are designed.Make sure the closed-loop system works stably and the control system is fast.The research content of this paper is verified by simulation and experiment.An experimental prototype with an input voltage of 100V, an output voltage of 200V-400V and a frequency of 100kHz is made. The waveforms of the primary side inductor current in all working states are tested, and the theoretical analysis and simulation results are verified.Secondly, the soft switching characteristics of the primary and secondary side switches under different loads with output voltages of 200V and 400V are verified in the state of DCM.Finally, the stability and rapidity of the closed loop control system are verified.The experimental results reach the expected design goal and target.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TM46;U469.72

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本文編號：1732465