低压大电流高频开关电源同步整流技术的研究-电气工程专业论文.docxVIP

低压大电流高频开关电源同步整流技术的研究 摘 要 随着互联网技术、微电子技术和通信技术的快速发展，IC 芯片和 DSP(数 字信号处理器)的普及应用，人们对稳压电源的要求越来越高。低输入电压可以 提高高速处理系统的速度并减小用电设备的功率损耗。但是低电压输出和随之 而来的大电流输出对开关电源来说，意味着效率提高的困难。目前普遍采用的 方法是采用同步整流技术来降低整流损耗。如何优化电路拓扑，合理驱动同步 整流管，努力提高低压大电流输出 DC/DC 变换器的效率成为当前电力电子技术 领域研究的一个热点课题。 本文着重对低压大电流输出的各种DC/DC变换器拓扑和同步整流技术进行 了分析研究。最终得到的优选组合是SR（Synchronous Rectification）-有源 钳位正激式变换器。本文的关键内容在于对SR-有源钳位正激式变换器进行了深 入的研究，提出了一种简单的控制驱动方法。通过对电路元器件参数的计算和 选择，设计出了实际电路，并通过Saber软件对主电路进行了仿真。 关键词：开关电源，同步整流，有源钳位，正激变换器 The Research of Synchronous Rectification in Low-voltage and High-current High-frequency switching power supply ABSTRACT Along with the rapid development of information technology, communication technology and micro electronic technique, and the popularization of IC chip and DSP (digital signal processor), the performance of regulated power supply has become increasingly demanding. Low-input-voltage is helpful to reduce the power attenuation of the equipments and to increase the speed of high-speed processing systems. However, low voltage output and consequent high current means low efficiency for switching power supply. Currently, the method to reduce rectifier loss based on synchronous rectification is used generally. Optimizing circuit topologies, driving synchronous rectifier diodes reasonably and raising the efficiency of low-voltage high-current DC-DC converters have now become the power electronic technology research hot spot. This paper gives an analysis and study on the circuit topologies and synchronous rectification of various kinds of low-voltage high-current DC-DC converters. The result shows that optimum combination is SR-active clamp forward converter. So this paper does an in-depth research in SR-active clamp forward converter and proposes a simple driving method. Through calculating and selecting the parameters of circuit components, an actual circuit is designed and simulated by the Saber software. Key words: switching power supply，synchronous rectification，active cla