基于移相全桥倍流同步整流变换器的设计

发布时间：2019-06-17 08:50

【摘要】：随着信息技术的快速发展,低压大电流变换器在计算机、通信等领域中得到广泛的应用。现在的低压大电流变换器大都采用隔离型BUCK变换器,为了降低变换器输入直流母线损耗和减小输入滤波器的体积,变换器的输入电压在不断的提高,而变换器的输出电压更低,输出电流更大,开关频率不断提高,因此传统的BUCK变换器已不能满足低压大电流变换器的要求。本文在分析国内外低压大电流变换器发展的基础上,通过对几种典型主电路拓扑的对比选择,确立了全桥倍流同步整流电路为主电路拓扑,并对其工作原理以及工作模态作了理论分析。在低压大电流输出场合,采用同步整流技术可以弥补传统二极管整流损耗大的缺点,实现了高效率的DC-DC变换。采用倍流整流技术,由于两个输出滤波电感交错并联,可以有效的抑制输出电流纹波,减小电感的尺寸。目前,对全桥变换器的研究大都采用移相控制技术,本文采用移相控制技术,并利用变压器的漏感同开关器件的结电容实现全桥开关管的软开关,减小了开关管的开关损耗,进一步提高了变换器的效率。本文采用电压闭环控制,提高整个变换器的稳定性。UC2875是一款移相谐振控制器,它的控制方式完全符合全桥倍流同步整流软开关变换器的需求。HIP4081是一款高频全桥FET驱动器,能够输出四路相互隔离的驱动脉冲。本文使用UC2875和HIP4081共同实现主电路的移相控制,给出了主开关器件实现ZVS的具体条件和参数设计,同时对设计了变换器的主电路、控制方法、变压器,并使用PSPICE仿真软件对变换器系统进行了仿真验证,仿真结果与理论分析一致。最后,本文以上述理论为基础,成功设计了一台输入36~60V,开关频率100KHz,输出3.3V,0~15A的变换器实验样机,其各项实验结果均满足设计指标要求,实验验证了所做理论分析的正确性。
[Abstract]:With the rapid development of information technology, low voltage and high current converters have been widely used in computer, communication and other fields. At present, most of the low-voltage and high-current converters use isolated BUCK converters. In order to reduce the input DC bus loss and reduce the volume of the input filter, the input voltage of the converter is constantly improving, while the output voltage of the converter is lower, the output current is larger, and the switching frequency is constantly increasing. Therefore, the traditional BUCK converter can no longer meet the requirements of low-voltage and high-current converters. In this paper, based on the analysis of the development of low voltage and high current converters at home and abroad, through the comparison and selection of several typical main circuit topologies, the main circuit topology of full bridge current doubling synchronous rectifier circuit is established, and its working principle and working mode are analyzed theoretically. In the case of low voltage and high current output, synchronous rectification technology can make up for the shortcomings of traditional diode rectifier loss, and realize high efficiency DC-DC transformation. The current doubling rectifier technology can effectively suppress the output current ripples and reduce the size of the inductance because of the staggered parallel connection of the two output filter inductors. At present, the phase shift control technology is mostly used in the research of full bridge converter. In this paper, the phase shift control technology is adopted, and the soft switching of the full bridge switch is realized by using the leakage inductance of the transformer and the junction capacitance of the switching device, which reduces the switching loss of the switch tube and further improves the efficiency of the converter. In this paper, voltage closed-loop control is used to improve the stability of the converter. UC2875 is a phase-shifting resonant controller, which fully meets the requirements of full-bridge current doubling synchronous rectifier soft-switching converter. HIP4081 is a high frequency full-bridge FET driver, which can output four isolated driving pulse from each other. In this paper, UC2875 and HIP4081 are used to realize the phase shift control of the main circuit, and the specific conditions and parameter design of the main switching device to realize ZVS are given. at the same time, the main circuit, control method and transformer of the converter are designed, and the converter system is simulated and verified by PSPICE simulation software. The simulation results are consistent with the theoretical analysis. Finally, based on the above theory, an experimental prototype of converter with input 36 鈮，

本文编号：2500865