高功率密度小功率DC-DC变换器的研究
发布时间：2018-07-17 02:47
【摘要】：开关电源在各类电子设备中以体积小、重量轻、转换效率高等优点成为研究热点。小功率开关电源的发展方向趋于高频化与小型化,但是,由于部分电子元件的约束,功率密度很难进一步提高。本文从四个途径进行隔离型高功率密度变换器的研究:(1)电路拓扑结构通过几种常用隔离型开关电源电路拓扑结构的对比分析,选择反激变换器的拓扑结构。通过对其工作原理及工作模式的分析,确定电流断续工作模式。根据开关电源的性能指标,对主功率电路关键元器件进行参数计算和选型。(2)提高开关频率高频可以减小磁性元件的体积,将开关管的工作频率定为500kHz。选取2MHz峰值电流控制模式的LM5022控制芯片,并对芯片外围电路的设计及控制模式作了详细的介绍。反激变换器在高频关断时,会产生很大的尖峰电压,RCD吸收电路可保证开关管安全可靠工作。(3)采用GaN开关器件GaN材料具有导通电阻较小、栅极电荷少、反向恢复电荷少、封装极小的特点,在高速开关和低导通电阻方面优势明显,将其应用于高功率密度领域。针对GaN晶体管驱动电压窄的特点,选取GaN晶体管单管专用驱动芯片LM5114,设计的独立推挽输出驱动电路能可靠稳定的驱动GaN开关管。(4)采用平面变压器磁芯元件平面结构具有较大的散热面积,降低元件热点与磁性元件表面的热阻,提高了功率密度。平面变压器的制作与设计难度大,本文总结了其设计步骤与制作方法,通过反激式高频变压器详述了设计过程,设计了一款转换效率为98.012%,尺寸大小为18×10×6mm3的平面变压器。通过以上四种途径,研制出一款输入24V,输出5V/5A,工作频率为500kHz,尺寸为34mm×18mm×6mm,效率是70.7%,功率密度为6.8W/cm3的隔离型开关电源样机。实验结果及分析验证该样机是一款体积小,质量轻,电磁兼容性好的高功率密度开关电源。
[Abstract]:Switching power supply (SMPs) has become a research hotspot in all kinds of electronic devices because of its small size, light weight and high conversion efficiency. The development trend of low power switching power supply tends to be high frequency and miniaturization, but it is difficult to improve the power density because of the restriction of some electronic components. This paper studies the isolated high power density converter in four ways: (1) the topology of the flyback converter is selected by comparing and analyzing the topology of several common isolated switching power supply circuits. Through the analysis of its working principle and working mode, the current intermittent working mode is determined. According to the performance index of switching power supply, the parameters of key components of main power circuit are calculated and selected. (2) the volume of magnetic element can be reduced by increasing the high frequency of switch frequency, and the working frequency of switch tube is set at 500 kHz. The LM5022 control chip with 2MHz peak current control mode is selected, and the design and control mode of the peripheral circuit of the chip are introduced in detail. When the flyback converter is turned off at high frequency, a large peak voltage and RCD absorption circuit can be produced to ensure the safe and reliable operation of the switch. (3) the gan material with gan switch device has lower on-resistance, less gate charge and less reverse recovery charge. It has the advantages of high speed switch and low on-resistance, so it is used in high power density field. Aiming at the narrow driving voltage of gan transistor, The single transistor driver LM5114is selected, and the independent push-pull output drive circuit is designed to drive the gan switch reliably and stably. (4) the planar structure of the planar transformer core element has a large heat dissipation area. The thermal resistance of the hot spot and magnetic element surface is reduced, and the power density is increased. It is very difficult to make and design plane transformer. This paper summarizes the design steps and methods, describes the design process of flyback high frequency transformer, and designs a plane transformer with conversion efficiency of 98.012 and size of 18 脳 10 脳 6mm3. Through the above four ways, a prototype of an isolated switching power supply with input 24V, output 5V / 5A, working frequency 500kHz, dimension 34mm 脳 18mm 脳 6mm, efficiency 70.7 and power density 6.8W / cm3 has been developed. The experimental results and analysis show that the prototype is a high power density switching power supply with small volume, light weight and good electromagnetic compatibility.
【学位授予单位】：湖北工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM46
[Abstract]:Switching power supply (SMPs) has become a research hotspot in all kinds of electronic devices because of its small size, light weight and high conversion efficiency. The development trend of low power switching power supply tends to be high frequency and miniaturization, but it is difficult to improve the power density because of the restriction of some electronic components. This paper studies the isolated high power density converter in four ways: (1) the topology of the flyback converter is selected by comparing and analyzing the topology of several common isolated switching power supply circuits. Through the analysis of its working principle and working mode, the current intermittent working mode is determined. According to the performance index of switching power supply, the parameters of key components of main power circuit are calculated and selected. (2) the volume of magnetic element can be reduced by increasing the high frequency of switch frequency, and the working frequency of switch tube is set at 500 kHz. The LM5022 control chip with 2MHz peak current control mode is selected, and the design and control mode of the peripheral circuit of the chip are introduced in detail. When the flyback converter is turned off at high frequency, a large peak voltage and RCD absorption circuit can be produced to ensure the safe and reliable operation of the switch. (3) the gan material with gan switch device has lower on-resistance, less gate charge and less reverse recovery charge. It has the advantages of high speed switch and low on-resistance, so it is used in high power density field. Aiming at the narrow driving voltage of gan transistor, The single transistor driver LM5114is selected, and the independent push-pull output drive circuit is designed to drive the gan switch reliably and stably. (4) the planar structure of the planar transformer core element has a large heat dissipation area. The thermal resistance of the hot spot and magnetic element surface is reduced, and the power density is increased. It is very difficult to make and design plane transformer. This paper summarizes the design steps and methods, describes the design process of flyback high frequency transformer, and designs a plane transformer with conversion efficiency of 98.012 and size of 18 脳 10 脳 6mm3. Through the above four ways, a prototype of an isolated switching power supply with input 24V, output 5V / 5A, working frequency 500kHz, dimension 34mm 脳 18mm 脳 6mm, efficiency 70.7 and power density 6.8W / cm3 has been developed. The experimental results and analysis show that the prototype is a high power density switching power supply with small volume, light weight and good electromagnetic compatibility.
【学位授予单位】：湖北工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM46
【参考文献】
相关期刊论文 前10条
1 谭琳琳;王康平;宇文甸;杨旭;;基于GaN器件LLC谐振变换器的平面变压器优化设计[J];电源学报;2016年04期
2 邹学文;董舟;周Z，
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