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Student: Guan-Ting, Lin Advisor: Ming-Shyan, Wang
Buck Converter Design Student: Guan-Ting, Lin Advisor: Ming-Shyan, Wang 2018/8/1
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Robot and Servo Drive Lab.
Outline Introduction Circuits analysis Element designs Hardware IsSpice simulation Optical coupler Snubber Circuits Experimental result Conclusion References 2018/8/1 Robot and Servo Drive Lab.
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Robot and Servo Drive Lab.
Introduction 許多應用都需使用電壓轉換器，諸如攜帶式設備，車載電子設備等，這是因為其電池的輸出電壓具有相當大的變化，因此，開關式電源是不可缺少的，能在不同的輸入電壓產生穩定的輸出電壓。 目前多種電壓轉換器，如boost converter、Zeta converter、 Luo converter 等，其操作模式多使用電流連續模式(CCM)，取其切換損失小、電流諧波小優點。 2018/8/1 Robot and Servo Drive Lab.
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Robot and Servo Drive Lab.
Circuits analysis 元件為理想。 電路操作於穩態情況下。 電感電流為連續(CCM模式)。 電容很大，輸出電壓保持為Vo。 切換週期為T ; 開關閉合時間為DT ，打開時間為(1- D)T。 2018/8/1 Robot and Servo Drive Lab.
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Robot and Servo Drive Lab.
Circuits analysis Switch open 當降壓式轉換器電路開關打開時，二極體變為順偏壓，電感會經由二極體來進行放電。 Switch close 當降壓式轉換器電路開關閉合時，此時二極體為逆向偏壓，因此電流從電源端流向電感，並且對電感進行充電。 伏秒平衡 2018/8/1 Robot and Servo Drive Lab.
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Robot and Servo Drive Lab.
Element designs 2018/8/1 Robot and Servo Drive Lab.
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Robot and Servo Drive Lab.
Element designs 2018/8/1 Robot and Servo Drive Lab.
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Robot and Servo Drive Lab.
Element designs Vin=48V，Vo=12V，Po=30W，fs=100kHz，操作在CCM模式，漣波電壓小於1%。 確保CCM模式，求出最小電感值： 確保漣波小於1% ，求出最小電容值： 2018/8/1 Robot and Servo Drive Lab.
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Robot and Servo Drive Lab.
Hardware 實際硬體圖 2018/8/1 Robot and Servo Drive Lab.
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Robot and Servo Drive Lab.
IsSpice simulation Vin 48V Vo 12V Po 30W R1 5Ω L1 36 μH C3 820 μF f 100 K Hz Duty 0.25 2018/8/1 Robot and Servo Drive Lab.
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Robot and Servo Drive Lab.
Optical coupler 光耦合隔離電路架構圖 2018/8/1 Robot and Servo Drive Lab.
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Robot and Servo Drive Lab.
Snubber circuits 未加Snubber電路_實際 Vds-Vgs關係圖 加入Snubber電路_實際 Vds-Vgs關係圖 2018/8/1 Robot and Servo Drive Lab.
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Robot and Servo Drive Lab.
Experimental result 模擬Vgs-Vds關係圖 實際 Vgs-Vds關係圖 2018/8/1 Robot and Servo Drive Lab.
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Robot and Servo Drive Lab.
Experimental result 模擬Vgs-VL關係圖 實際 Vgs-VL關係圖 2018/8/1 Robot and Servo Drive Lab.
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Robot and Servo Drive Lab.
Experimental result 模擬VL-IL關係圖 實際VL-IL關係圖 2018/8/1 Robot and Servo Drive Lab.
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Robot and Servo Drive Lab.
Experimental result 模擬VL-Ic關係圖 實際VL-Ic關係圖 2018/8/1 Robot and Servo Drive Lab.
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Robot and Servo Drive Lab.
Experimental result Pin=48*0.619= Po=2.25*11.8= 效率=89% 模擬Vgs-Vo關係圖 實際Vgs-Vo關係圖 2018/8/1 Robot and Servo Drive Lab.
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Robot and Servo Drive Lab.
Experimental result Pin=48*0.619= Po=2.25*11.8= 效率=89% 實際VL-Iin關係圖 2018/8/1 Robot and Servo Drive Lab.
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Robot and Servo Drive Lab.
Conclusion 切換頻率高時，L and C 可選用較小，成本較低，不過需考慮高頻震盪因素。 CCM模式下，切換損失小，電流諧波小，適合用於高電壓高電流電路。 Snubber circuits能有效降低突波，switch耐壓可選用較小，成本較低，但功率會下降。 2018/8/1 Robot and Servo Drive Lab.
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Robot and Servo Drive Lab.
References [1] K. I. Hwu , Member, and T. J. Peng “A Novel Buck–Boost Converter Combining KY and Buck Converters” IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 27, NO. 5, MAY [2] Lung-Sheng Yang, Tsorng-Juu Liang, Member, and Jiann-Fuh Chen “Transformerless DC–DC Converters With High Step-Up Voltage Gain” IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 56, NO. 8, AUGUST [3] Harada, K, and Sakamoto, H “Switched snubber for high frequency switching” Power Electronics Specialists Conference, PESC '90 Record., 21st Annual IEEE. [4] Volkan Kursun, Siva G. Narendra, Vivek K. De, and Eby G. Friedman “Efficiency Analysis of a High Frequency Buck Converter for On-Chip Integration with a Dual-VDD Microprocessor”. 2018/8/1 Robot and Servo Drive Lab.
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Robot and Servo Drive Lab.
Thank for listening 2018/8/1 Robot and Servo Drive Lab.
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