高效率高功率密度acdc变换器研究.docx

浙江大学硕士学位论文 摘要
摘要
随着信息通讯技术的发展,开关电源广泛的用于各个领域。由于能源危机和环境问题的日益严重,对开关电源的效率提出更高的要求,另一方面,电子设备的小型化要求减小开关电源体积,高效率、高功率密度成为开关电源发展的重要方向。本文以提高开关电源效率和功率密度为目标,着重针对PFC和DC/DC变换电路进行了研究。
为了满足电能质量的要求,功率因数校正电路成为电源中必不可少的一部分。论文分析比较了多种Boost型PFC方案,M Boost PFC、无桥 PFC、倍压PFC及低频PFC,在此基础上提出了一种新型的具有窗口控制和有源整流桥的PFC方案,并介绍了该PFC方案的主电路和控制电路设计方法,特别是窗口控制电路和有源整流桥驱动电路的设计。
LLC谐振变换器可以在宽输入电压范围内实现原边开关管的ZVS开通,既可以工作在升压模式也可以工作在降压模式,有利于电源中保持时间的实现,同时实现额定输入电压时效率的优化,因此被选定为DC/DC级实现方案。本文介绍了LLC电路的工作原理及直流增益特性,探讨了LLC电路的谐振参数设计方法,研究了LLC小信号建模及闭环设计方法。
论文在上述分析研究的的基础上,研制了一台500W实验样机,首先对PFC 变换器和LLC变换器分别进行了实验测试,然后给出了两级电路联调的测试结果,验证了理论分析和设计的正确性。
关键词:高效率,高功率密度,Boost,PFC,AC/DC变换器,LLC,同步整流
浙江大学硕士学位论文 Abstract
Abstract
With the rapid development of information munication technologies, switching mode power supply(SMPS)has been widely used in all a result of ever increasing energy crisis and environment problem,higher demand has been presented on the efficiency of the other hand,MiniaturiTztion of electronic equipment requires reduction of volume of SMPS,high efficiency and high power
density e the important development direction of thesis mainly
researches the PFC converter and DC/DC converter,aimed to improve the efficiency
and power density.
To meet the requirement of power quality,power factor correction circuit(PFC) has e an indispensable part of power this paper,several types of Boost PFC are analyzed and made parison,including M Boost
PFC,Bridgeless PFC,Voltage Doubler PFC,and low frequency the basis of above analysis,a novel PFC with enabling window control and active input bridge is proposed,the design method of main circuit and control circuit of proposed PFC
circuit is shown,especially the design of enabling window control circuit and drive circuit of active input bridge.
For LLC resonant converter,the zerO voltage switching(zvs)for primary switches Can be achieved in a wide input voltage the LLC converter call be
worked in either step-up mode or step—down