高功率因数的带同步整流半桥LLC谐振电路的研究

发布时间：2019-04-13 10:06

【摘要】：随着消费类电子和信息技术(IT)产品的快速更新换代,开关电源的小型化高效化成为了必然的发展趋势。为了降低电流谐波对电网的污染,提高电网供电的质量,开关电源通常采用前级为功率因数校正(PFC)器、后级为DC-DC变换器的两级电路拓扑结构。采用交错并联Boost变换器构建前级PFC电路,可以降低输入、输出电流纹波和开关管的电流应力,提高电路的功率密度,控制方案采用基于电感电流临界导通(CRM)模式的恒定导通时间控制,可以简化电路结构,降低开关损耗和电磁干扰(EMI)；LLC谐振变换器因其软开关特性,适合工作在高开关频率场合,且输入电压范围宽,动态响应能力强,成为了后级DC-DC变换器的首选电路拓扑,为进一步提高低压输出场合的效率,将同步整流技术引入LLC谐振变换器,采用检测漏源极电压的方法来实现对同步整流管的控制。在上述基础上,详细地分析了高功率因数的带同步整流半桥LLC谐振电路的工作原理,介绍了电路的具体设计过程和参数选择依据,最后,分别研制了两台实验样机,一台为300W的交错并联Boost型PFC样机,另一台为240W的带同步整流半桥LLC谐振电路样机,并将两者进行级联调试,给出相应的实验波形。实验结果表明：系统变换电路获得了高功率因数和高效率。
[Abstract]:With the rapid upgrading of consumer electronics and information technology (IT) products, the miniaturization and efficiency of switching power supply has become an inevitable trend of development. In order to reduce the pollution of current harmonic to the power grid and improve the quality of power supply, the switching power supply usually adopts the two-stage circuit topology of the first stage as power factor correction (PFC) and the second stage as DC-DC converter. An interleaved Boost converter is used to construct the front-stage PFC circuit, which can reduce the input and output current ripple and the current stress of the switch transistor, and improve the power density of the circuit. The control scheme adopts constant on time control based on the inductor current critical conduction (CRM) mode, which can simplify the circuit structure and reduce the switching loss and electromagnetic interference (EMI);). Due to its soft-switching characteristics, LLC resonant converter is suitable for high switching frequency, and has a wide input voltage range and strong dynamic response. It has become the first choice of circuit topology for later-stage DC-DC converter. In order to improve the efficiency of low voltage output, the synchronous rectifier technology is introduced into the LLC resonant converter, and the control of the synchronous rectifier is realized by detecting the drain source voltage. On the basis of the above, the working principle of the high power factor half bridge LLC resonant circuit with synchronous rectifier is analyzed in detail. The specific design process and parameter selection basis of the circuit are introduced. Finally, two experimental prototypes are developed respectively. One 300W interleaved boost PFC prototype and the other 240W LLC resonant circuit prototype with synchronous rectifying half-bridge were debugged and the corresponding experimental waveforms were given. The experimental results show that the system achieves high power factor and high efficiency.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM461

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